Is methodological naturalism a defining feature of science?

(Part Five in a series in response to Zack Kopplin.)

A. What is Methodological Naturalism, and is it an essential part of the scientific method?

In this mosaic, from a Roman villa in Sentinum, ca. 200 to 250 A.D., Aion, the god of eternity, is standing inside a celestial sphere decorated with zodiac signs, in between a green tree and a bare tree (summer and winter, respectively). Sitting in front of him is the mother-earth goddess of Nature, Tellus (the Roman counterpart of Gaia) with her four children, who possibly represent the four seasons. (Munich Glyptothek, Inv. W504.) Image courtesy of Wikipedia.

Looking through all the letters in support of your campaign, Zack, I've noticed a common theme: a desire to keep religion out of the science classroom. That's highly commendable. But where do you draw the line between science and religion? The criterion that's usually invoked today is that of methodological naturalism: science should confine itself to naturalistic explanations, and it should never invoke or appeal to the supernatural.

Four definitions of methodological naturalism

I'd like to begin by examining four definitions of methodological naturalism which I've encountered in the literature. I'll argue below that all of these definitions share a common flaw, which I shall attempt to remedy by putting forward an improved definition of my own, which not only explains what the term means, but why it is commonly regarded - mistakenly, in my view - as an essential part of scientific methodology.

The definition of methodological naturalism (MN) which I propose is a fairly robust one, and some proponents of MN might regard it as too strong, since (as I will argue below) adherents of a large number of religions hold contrary beliefs. I then contrast my definition of methodological naturalism with a weaker alternative version which contains a different rationale for why MN an essential part of scientific methodology. This version is based on arguments put forward by Professor Robert Pennock. I argue that this weaker definition of MN is untenable, as it would logically entail that more advanced intelligent life-forms than ourselves either don't exist anywhere in the cosmos (which violates the Copernican principle, beloved by anti-supernaturalists) or that these highly intelligent life-forms are in principle undetectable by us (which is absurd, as it would surely be easy for them to send us a signal encoding mathematical or scientific information which unambiguously confirmed their presence). Finally, I examine an even weaker version of MN, which bans references to supernatural agents in science, on the grounds that science has so far succeeded in explaining phenomena without having to invoke these agents. I argue that if this principle were allowed to stand, scientists would also have to ban, on methodological grounds, all references to any new or speculative scientific concept - which would mean that such concepts could never be tested and that science could never progress.

I conclude that my stronger definition of methodological naturalism is the only one that can stand, which means that if it is regarded as a vital part of scientific methodology, then people of many religious persuasions cannot be scientists.

I would now like to begin by examining some common definitions of methodological naturalism.

My first definition of methodological naturalism comes from Wikipedia, which provides a handy explanation of the term in its article on Naturalism (philosophy):

Methodological naturalism is concerned not with claims about what exists but with methods of learning what is nature. It is strictly the idea that all scientific endeavors — all hypotheses and events — are to be explained and tested by reference to natural causes and events. The genesis of nature, e.g., by an act of God, is not addressed.

My second definition is taken from Part One of an essay by Assistant Professor Peter S. Williams, entitled, Intelligent Designs on Science: A Surreply to Denis Alexander's Critique (2006). Williams' definition of "methodological naturalism" is essentially the same as Wikipedia's. Williams also provides a helpful explanation of the origin of the term:

Indeed, the phrase 'methodological naturalism' was apparently coined by theistic evolutionist Paul de Vries in a 1983 conference paper subsequently published as "Naturalism in the Natural Sciences," Christian Scholar's Review, 15 (1986), 388-396. De Vries distinguished between 'methodological naturalism', as a disciplinary method that is neutral concerning God's existence and 'metaphysical naturalism', which 'denies the existence of a transcendent God.' Hence De Vries states that the goal of the natural sciences is: 'to place events in the explanatory context of physical principles, laws, fields... the natural sciences are committed to the systematic analysis of matter and energy within the context of methodological naturalism.'[69] Methodological naturalism (MN) has thus been defined as the idea that: 'scientific method requires that one explain data by appealing to natural laws and natural processes.'[70]

References
[69] Paul de Vries, 'Naturalism in the Natural Sciences,' Christian Scholar's Review, 15 (1986), 388-396.
[70] Garrett J. DeWeese & J.P. Moreland, Philosophy Made Slightly Less Difficult, (Downers Grove: IVP, 2005), p. 133.

My third definition of "methodological naturalism" is taken from is the locus classicus for the term: Paul de Vries' original 1983 essay, "Naturalism in the Natural Sciences." The following passage is especially pertinent:

I let go of my pencil and it immediately falls to the floor. Why? It would not be scientifically enlightening to say, "God made it that way." Similarly, scientists would not explain a particular rainstorm in terms of an Indian's rain dance or a farmer's prayers. Rainstorms are explained in terms of natural factors, such as air pressure and temperature — factors that themselves depend on other natural factors.

In brief, explanations in the natural sciences are given in terms of contingent, non-personal factors within the creation. If I put two charged electrodes in water, the hydrogen and oxygen will begin to separate. If I were writing a lab report (even at a Christian College!), it would be unacceptable to write that God stepped in and made these elements separate. A "God Hypothesis" is both unnecessary and out of place within natural scientific explanations.

The naturalistic focus of the natural sciences is simply a matter of disciplinary method. It is certainly not that some scientists have discovered that God did not make phenomena occur the way they do. The original causes or ultimate sources of the patterns of nature are not proper concerns within any of the natural sciences — though they remain a wholesome and legitimate concern of many natural scientists. The natural sciences are limited by method to naturalistic foci. By method they must seek answers to their questions within nature, within the non-personal and contingent created order, and not anywhere else. Thus, the natural sciences are limited by what I call methodological naturalism. (p. 289)

For de Vries, then, the term "methodological naturalism" signifies an agreement, on the part of the scientific community, to confine its explanations of phenomena to those which invoke contingent, non-personal factors - and nothing else. Hence methodological naturalism necessarily excludes all appeals to miracles as scientific explanations of natural phenomena. De Vries takes pains to emphasize, however, that methodological naturalism does not prohibit scientists from appealing to God as an ultimate explanation of natural phenomena - provided that they make it clear that they are invoking God as a philosophical explanation rather than a scientific one.

My fourth and final definition of methodological naturalism comes from a widely-cited 2011 article by Professor Robert T. Pennock: "Can't philosophers tell the difference between science and religion?: Demarcation revisited" in Synthese 178(2), pp. 177-206, DOI: 10.1007/s11229-009-9547-3. Pennock's definition is succinct and to the point:

"MN [Methodological naturalism] holds that as a principle of research we should regard the universe to be a structured place that is ordered by uniform natural processes, and that scientists may not appeal to miracles or other supernatural intervention that breaks this presumed order. Science does not hold to MN dogmatically, because of reasons having to do with the nature of empirical evidence." (p. 184)

Intriguingly, Pennock seems to suggest in this passage that methodological naturalism is a revisable scientific principle - an interpretation he confirms later in his essay, when he writes that "MN [Methodological naturalism] is not dogma; it continues to be accepted in part because of its success - it works" (p. 199). He even hints that "if someone were to find a workable method of finding evidence for supernatural hypotheses" then scientists might consider "modifying the ground rule" of methodological naturalism (p. 199). However, he finds it "hard to even imagine what such an alternative method would look like" (p. 199), as "we have no experience and thus no knowledge of divine attributes" (p. 189). For these reasons, he contends that the Intelligent Design creationist's "call for a theistic science is ... unworkable" (p. 185).

What I'd like to argue is that none of the four definitions listed above constitutes an adequate formulation of the principle of methodological naturalism. A simple illustration will suffice to explain the flaw these definitions share. Suppose I were to define scientific methodology as follows: "the scientific method requires that one explain data by appealing to laws and processes beginning with the letter S." The reader would reasonably object that my definition was ad hoc, and that I had provided no justification whatsoever for my arbitrary exclusion of laws and processes beginning with letters other than S. In other words, a definition of scientific methodology which merely stipulates what kinds of explanations are to be called "scientific" is a very poor one. What we need is a definition of scientific methodology which authenticates itself: a definition which tells us not only what scientific methodology is, but why it works in that way and not some other way. In other words, what we need is a definition of scientific methodology which supplies its own epistemic warrant.

Let me be clear: I am not arguing here that defenders of methodological naturalism have failed to supply a rationale for their definition of scientific methodology. As we have seen, De Vries puts forward a highly persuasive rationale - which I shall critique below - in the paragraphs preceding his own definition, and Professor Pennock, in his 2011 essay, takes pains to lay out the scientific rationale for methodological maturalism. Rather, the point I wish to make is that the rationale for any good definition of scientific methodology should be contained within the definition itself, so that we need look no further when we ask ourselves why science has to work that way.

It needs to be borne in mind that methodological naturalism is a very powerful scientific claim. It has to be, in order to banish all talk of the supernatural from the domain of science - which is something that de Vries certainly wanted his definition to accomplish, since he insists that scientists "[b]y method ... must seek answers to their questions within nature, within the non-personal and contingent created order, and not anywhere else." If we are to banish God-talk from science, then we need to be very clear about why we are doing so.

What are the criteria for identifying things which are natural?

Before we can define methodological naturalism properly, we need to define the word "natural." How can we tell if something is natural or not? I would suggest that the following set of properties can be regarded as hallmark properties of natural entities:

(a) mutability, or the ability to undergo change;

(b) fixed dispositions, or uniform (i.e. regular) behavioral tendencies, which serve to characterize that object as a member of some natural kind, whose boundaries may be either sharp (e.g. the element oxygen) or fuzzy (e.g. a biological species such as the herring gull, Larus argentatus);

(c) interactive causation in space-time, or the ability to affect and be affected by the behavior of other natural objects, within some spatio-temporal domain;

(d) scientific laws describing all of the entity's behavioral dispositions, which are [ultimately] mathematical in form, and whose parameters are all capable of being quantitatively measured by some instrument; and finally,

(e) total contingency: for each and every one of an entity's attributes, scientists can meaningfully ask: "What makes it that way, and not some other way?"

On the definition of "natural" which I am employing here, the term "natural" means roughly the same as "physical." The term "empirical," on the other hand, is narrower in scope, as it only refers to things that we can observe, either directly (with our senses) or indirectly (using some instrument which then relays a signal to our senses). Thus any object within the observable universe is empirical, but objects in some other universe which is causally isolated from us are not empirical objects.

On my usage, the term "natural" may be legitimately contrasted not only with "supernatural", but with anything non-physical, whether it be God or a disembodied spirit. (Thus my definition of "natural" differs from the definition which a theologian would use. For a theologian, the last trait, contingency, would suffice to identify something as natural, as necessity is a hallmark trait of the Creator alone. The other four traits would not necessarily apply to spirits.)

The term natural, as I am using it, is not meant to be contrasted with "artificial", but with "spiritual". Thus an intelligent agent would qualify as natural if - and only if - it satisfies the definition given above.

What methodological naturalism is not - and what it is

I contend that methodological naturalism is a very strong methodological principle, which should not be confused with a number of weaker principles, for example:

(a) the principle that scientific questions are not to be resolved by appealing to the tenets of some revealed religion;

(b) the principle that science can be defined as the systematic study of physical phenomena, which are by definition part of Nature;

(c) the principle that science is limited to the study of regularly occurring phenomena - or alternatively, that science is limited to the study of replicable phenomena;

(d) the principle that scientists should look for natural explanations before invoking supernatural ones;

(e) the principle that scientists should avoid appealing to miracles, when attempting to account for physical phenomena; or even

(f) the principle that scientists should look for natural proximate causes when attempting to account for physical phenomena;

(g) the principle that scientists should confine themselves to natural causes, whether proximate or remote, when attempting to account for physical phenomena.

Many people might be inclined to identify methodological naturalism with principle (g), but I will argue below that they are mistaken: a more robust principle is required, in order for methodological naturalism to do the job it was intended to do.

If methodological naturalism is to banish all talk of the supernatural from the domain of science and establish science as an autonomous discipline in its own right, then it has to accomplish two objectives:

first, it has to maximize the scope of scientific explanations, in such a way as to bring all (and not just some or most) physical phenomena within the domain of science, so as to leave no room for phenomena which may require a supernatural explanation; and

second, it has to eliminate appeals to the supernatural, when attempting to explain observed phenomena.

Accomplishing the first objective is vital. For if there were a special category of unexplained physical phenomena which fell outside the domain of science, then the possibility that these phenomena required a supernatural explanation could not be ruled out. The existence of a category of unexplained (and possibly supernatural) phenomena would also threaten the autonomy of science, as there would be no way to prevent these phenomena from interfering with ordinary phenomena that scientists claimed to be able to explain.

The necessity of meeting the second objective should be obvious enough, for unless scientists can eliminate appeals to the supernatural when attempting to explain physical phenomena, methodological naturalism will never be successfully implemented, as a program for doing science.

None of the seven principles listed above accomplishes both of these objectives.

Principle (a): Scientists shouldn't resolve scientific questions by appealing to the tenets of revealed religions

Principle (a) says nothing about the scope of scientific explanations. In particular, it does not tell us whether science is able to explain all physical phenomena, or merely a large subset of those phenomena. Thus it fails to meet the first objective. Additionally, while it successfully eliminates appeals to the tenets of any religion when attempting to account for empirical phenomena, it nonetheless fails to eliminate appeals to the supernatural, when attempting to explain observed phenomena. For instance, principle (a) is perfectly compatible with natural theology: the quest to arrive at a knowledge of God based on observed facts and experience, apart from divine revelation. Such a God, if postulated as an ultimate explanation of physical phenomena, would be a supernatural Being. Thus principle (a) not only fails to meet the first objective, but it fails to satisfy the second as well.

Principle (b): Science is the study of physical phenomena which are found in Nature

Principle (b) also fails to satisfy either the first or the second objective. All it says is that the subject matter of science is physical phenomena, and only physical phenomena. However, nothing in this principle implies that science is competent to explain all physical phenomena. Moreover, the principle in no way implies that physical phenomena can be explained solely in terms of other physical phenomena. It could be the case, for instance, that while scientists can only study physical phenomena, they nevertheless have to invoke various non-physical phenomena - the proper study of which lies outside the domain of science - in order to fully account for the physical phenomena they observe in Nature. In other words, scientists might still be able to indirectly infer the existence of a non-physical (and possibly supernatural) realm, even though they are unable to study it directly. I therefore conclude that no self-professed supernaturalist has anything to fear from principle (b): methodologically, it is utterly innocuous.

Principle (c): Science is the study of regular phenomena (or alternatively, replicable phenomena)

Image of a large meteorite impact. Scientists hypothesize that the extinction of the dinosaurs and many other groups of organisms at the end of the Cretaceous period 65.5 million years ago was caused by one or more catastrophic events, including at least one asteroid impact (especially the one which created the Chicxulub crater) or possibly increased volcanic activity. Image courtesy of NASA and Wikipedia.

Likewise, principle (c) satisfies neither objective. It fails to meet the first objective, as it would severely narrow the scope of science, to exclude all singular events from its domain, thereby severely curtailing the scope of many of the historical sciences, which often have to deal with events which are not regular occurrences, or which are no longer replicable today. Not only would many "origin" events be excluded (e.g. the origin of the universe, or of life on Earth), but also one-off radiations of life occurring in the past (e.g. the Cambrian explosion) and more significantly, all catastrophic events, such as the Ice Ages or the K-T extinction event, caused by an asteroid impact, which killed off the dinosaurs and many other groups of organisms about 65.5 million years ago.

Aristotle and his medieval followers denied that singular anomalies resulting from chance and variability could belong to the subject matter of true science, since "there can be no demonstrative knowledge of the fortuitous." As a result, natural philosophy continued to restrict its investigations to common experience until the seventeenth century. (Aristotle, Posterior Analytics, 87b 19-20.)

In the modern era, the first scientist to mount a serious defense of principle (c) was Georges-Louis Leclerc, known as Comte de Buffon, who wrote in 1749 in his Theorie de la Terre that "The causes of rare, violent and sudden effects must not concern us, they are not part of the ordinary process of Nature" (quoted in Buffon: A life in natural history by Jacques Roger, Cornell University Press, 1997, p. 101). What Buffon wanted to do was to secure science's independence from theology, by excluding both miracles from the domain of science, but he did so at a very high cost: his methodological constraint forced him to exclude catastrophes from the scope of science as well. However, methodological naturalism is much more ambitious in its aims than Buffon's modest program for science; it endeavors to bring the entire range of observed phenomena under the domain of science. Because principle (c) deliberately narrows the scope of science, a modern-day methodological naturalist would therefore have no choice but to reject this principle.

What is more, principle (c) even fails to meet the second objective, of dispensing with appeals to the supernatural, since the only supernatural acts it would rule out are irregular ones - i.e. miracles. Moreover, one could argue that a miracle is not really an irregular occurrence, for as the nineteenth century mathematician Charles Babbage pointed out in his Ninth Bridgewater Treatise, even a singular value can be incorporated into the general description of a mathematical function. Babbage's point is readily grasped with the aid of a mathematical illustration. We can define a function y, as follows: y = 2x for x <> 100, y = 0 for x = 100. The apparently anomalous value of y when x = 100 is analogous to the occurrence of a miracle; it appears "irregular", but is in fact contained in the very definition of the function. Instead of calling it irregular, we should properly refer to it as discontinuous. The idea that God might have arranged in advance for miracles to occur at certain times in history when He created the world, by programming Nature at the outset to exhibit anomalous values for certain physical physical parameters at those times, might strike us as deeply distasteful, but Nature does not revolve around our aesthetic tastes.

Even if we were to generously grant that principle (c) precludes any appeals to miracles, a theistic proponent of principle (c) would be perfectly within his/her rights in attempting to explain natural phenomena by appealing to the supernatural but regular action of a Deity, Who maintains the world in existence and ensures that it behaves according to fixed laws.

In short: the reason why principle (c) fails to qualify as a genuinely naturalistic principle is that it only deals with the subject matter of science, which is defined as all regular or replicable natural phenomena. To rule out appeals to the supernatural, we need to limit not only the subject matter, but also the kinds of explanations that can be legitimately invoked in order to account for it. Rather than simply defining science as the study of regular or replicable phenomena, we should also say that the only explanations allowed in science are those which involve regular or replicable phenomena. Amended in this way, principle (c) does indeed rule out appeals to the supernatural, thereby satisfying the second objective. However, the claim is silent regarding whether all events occurring in the natural world (including one-off catastrophic events) can in fact be explained in scientific terms (by appealing to regular or replicable phenomena). Thus it still fails to meet the first objective.

Principle (d): Scientists should look for natural explanations before invoking supernatural ones

Principle (d) is merely a prudential maxim, which most supernaturalists would be quite happy to affirm. All it says is that we should look for natural explanations first, before invoking supernatural ones - which still leaves the door wide open to appeals to the supernatural, when all known natural explanations have been exhausted. Thus principle (d) fails to meet either the first objective listed above or the second: it does not tell us whether science will be able to explain all observed phenomena, and it fails to effectively exclude the supernatural from the domain of science.

Principle (e): Scientists should avoid appealing to miracles when accounting for physical phenomena

Principle (e) bars appeal to miracles by scientists, in the course of their work. But from a methodological naturalist perspective, principle (e) is still unsatisfactory, as it fails to meet either of the objectives listed above. Showing that a physical phenomenon is not miraculous does indeed entail that it is explicable in naturalistic terms, but that does not guarantee that it is explicable in purely naturalistic terms. For instance, scientific explanations at a proximate level might be entirely natural; but at the ultimate level of scientific explanation, a supernatural explanation might still be required. If we are to effectively banish the supernatural from the domain of science, then, we need a postulate which states that natural causes are sufficient to account for all observed phenomena. Thus principle (e) fails to satisfy the first objective stipulated above.

Second, principle (e) would mean that when faced with a mysterious phenomenon which totally confounds scientific explanations, scientists would still have the option of saying: "As a scientist I cannot explain that, but putting on my religious hat, I'd say we're witnessing a miracle here." (Think of the Lourdes Medical Bureau.) Thus principle (e) fails to meet the second objective as well.

I should add that if one also adopts principle (c), then principle (e) will be trivially true. Miracles are not required to invoke regularly occurring phenomena. Miracles are by definition extraordinary events; therefore they cannot be invoked to explain the ordinary. In Part D below, I will argue that medieval natural philosophers who upheld principle (e) did so only because they accepted principle (c): following Aristotle, they limited science to the study of regularly occurring natural changes. However, they also maintained that many events occurring in the world that appeared to be singular events (e.g. eclipses, earthquakes, epidemics) were in fact part of a regular pattern, and hence not miraculous. These philosophers did not reject miracles as such; rather, they wisely refrained from invoking them in order to explain what they believed to be regular events.

Principle (f): Scientists should look for natural proximate causes when attempting to account for physical phenomena

Detail of In hoc signo vinces (In this sign, conquer) by Raphael, Sala di Costantino, Vatican City. Image courtesy of NASA and Wikipedia. According to the historian Eusebius of Caesarea, Constantine I and his army had a vision of a chi rho on the sky, with the words "In this sign, conquer" in Greek emblazoned below it, just before the Battle of Milvian Bridge against Maxentius on 28 October 312 - a battle that Constantine went on to win, making him undisputed ruler of the Roman Empire. During the Middle Ages, this event was commonly accepted as a bona fide miracle. As such, it would have been regarded as a singular celestial phenomenon: the kind of event which falls outside the domain of science, according to medieval natural philosophers. Although they would have recognized this event as a miracle, these philosophers nevertheless adopted a very matter-of-fact attitude towards comets and eclipses, to which they assigned natural proximate causes, because they regarded them as regular events.

Principle (f) is also deficient from a methodological naturalist perspective, as it does not tell us whether science is able to explain the entire gamut of observed phenomena - which is the operating assumption that methodological naturalism needs to make, in order to satisfy the first objective listed above.

It is interesting to note that principle (f) would be robbed of its force if it were combined with principle (c), which stipulates that science should confine itself to the investigation of regular phenomena. All it would entail then is that regular phenomena have a natural proximate cause - a trivial point on which naturalists and supernaturalists alike would readily agree. As we shall see, this was precisely the view upheld by medieval natural philosophers in the thirteenth and fourteenth centuries, who wrote about celestial phenomena such as comets and eclipses. In their view, these phenomena were not singular but regular occurrences with a natural cause, and people who believed otherwise were credulous simpletons.

At the same time, however, these same philosophers would have acknowledged the miraculous nature of singular celestial phenomena of a portentous nature, which could not possibly be explained as regular events - for example, the cross in the sky with the words, "In this sign, conquer" emblazoned above it, that was allegedly witnessed by the Emperor Constantine and his entire army shortly before the Battle of Milvian Bridge in 312 A.D. - an event which was universally accepted in medieval Christian Europe as a miraculous act of supernatural intervention. My point here is that the natural philosophers of the thirteenth and fourteenth centuries who appealed to principles (c) and (f) in their scientific writings were not methodological naturalists, but rather, highly disciplined supernaturalists. Their use of principle (f) did not prevent them from invoking the supernatural miracles to explain celestial portents which could not be "regularized."

But the most serious problem with principle (f) is that it also fails to satisfy the second objective. It does not eliminate appeals to the supernatural, when attempting to explain physical phenomena; all it does is make the supernatural a remote rather than immediate explanation. Principle (f) is entirely compatible with the practice of looking for natural proximate causes for physical phenomena, while still invoking God as a First Cause - which is precisely what natural philosophers in the Middle Ages did.

Principle (g): Scientists should invoke only natural causes when attempting to account for physical phenomena

Many people (including, it seems, Paul de Vries) would equate methodological naturalism with principle (g). However, principle (g), like principle (f), says nothing regarding the competence of science to explain the entire gamut of natural phenomena - which is the operating assumption that methodological naturalism needs to make, in order to satisfy the first objective listed above. It does not tell scientists what they are to do when faced with phenomena which appear recalcitrant to a naturalistic explanation.

Additionally, principle (g) fails to satisfy the second objective. It does not eliminate appeals to the supernatural, when attempting to explain observed phenomena; all it eliminates is scientific appeals to the supernatural. A supernaturalist could consistently uphold principle (g), but at the same time maintain that observed phenomena also require a deeper, metaphysical explanation which goes beyond the phenomena themselves, to some underlying non-physical Cause.

At this point, a methodological naturalist might respond: "That's the whole point of the definition. Whether physical phenomena ultimately require a supernatural explanation is a question that science cannot answer, one way or the other. If it did, then methodological naturalism would collapse into metaphysical naturalism. So long as the supernaturalist you described above keeps God out of science, he/she is still a bona fide methodological naturalist."

What this response overlooks, however, is that the the raison d'etre of methodological naturalism is to protect the autonomy of science, as an intellectual mode of inquiry. Science's autonomy is guaranteed only if its explanations of observed phenomena are fully adequate. But if the empirical phenomena which science deals with cannot be fully explained within a scientific framework, but also require a theistic metaphysical framework in order to fully explain them, then the domain of science can no longer be isolated from that of theology, and science is no longer self-contained as a mode of inquiry.

A consistent methodological naturalist, then, must be committed to holding that science is capable of fully explaining phenomena as such. This does not mean, however, that methodological naturalism must collapse into metaphysical naturalism. The reason is that science says nothing about the inner reality, or being, of things. In Kantian terms, science does not deal with noumena, or things in themselves; rather, it deals with phenomena, or appearances. It is these phenomena which a consistent methodological naturalist must allow that science is fully capable of accounting for, without the need for any underlying metaphysical explanations. For instance, an Argument from Motion to the existence an Unmoved Mover (Aquinas' First Way) would fall foul of methodological naturalism, as I am construing it here, since motion (or change) is a natural phenomenon; whereas an Argument from Contingency to the existence of a Necessary Being (Aquinas' Third Way) would not, since being belongs in the realm of noumena.

It should be apparent by now that methodological naturalism goes much further than claims (a), (b), (c), (d), (e), (f) and (g). What it says can best be expressed by the following principle:

(h) When doing science, we should assume that natural causes are sufficient to account for all physical phenomena, and that for precisely this reason, all talk of the supernatural is banished from science.

Or as Professor Lawrence Lerner memorably put it in a short piece entitled, Methodological Naturalism vs Ontological or Philosophical Naturalism, which was excerpted from a longer article he published for the NCSE (February 14, 2003), entitled, Proposed West Virginia Science Standards: Evaluated by Lawrence Lerner, Attacked by Intelligent Design Creationists:

Methodological naturalism is not a "doctrine" but an essential aspect of the methodology of science, the study of the natural universe. If one believes that natural laws and theories based on them will not suffice to solve the problems attacked by scientists - that supernatural and thus nonscientific principles must be invoked from time to time - then one cannot have the confidence in scientific methodology that is prerequisite to doing science. The spectacular successes over four centuries of science based on methodological naturalism cannot be gainsaid.

It needs to be borne in mind that methodological naturalism (MN) is a methodological principle, not a metaphysical one. For instance, methodological naturalism does not assert that miracles never occur in the natural world - although anyone who accepted principle (h) could not consistently countenance them. Nor does methodological naturalism claim that the laws of Nature are never broken - although it would instantly be rendered invalid if they were. Finally, methodological naturalism does not assert that the natural world is all there is, or that nothing exists outside Nature, or that there are no supernatural beings. All of these statements are metaphysical claims, whereas the claim made by MN is a methodological one.

The robust version of methodological naturalism proposed here secures the autonomy of science, but at a price. It clashes with a key claim made about the world made by many of the world's leading religions - namely, that miracles have occurred on rare occasions in the past. Most Christians believe this (the Resurrection is an obvious example). Likewise, many Jews believe that the nature miracles recorded in the Tanakh [or what Christians call the Old Testament] actually occurred - for instance, the prophet Elisha's raising a dead boy to life in 2 Kings 4:29-37. Muslims also believe that God worked miracles in the past - e.g. through Noah (see Sura 11 and Sura 23). Belief in miracles is common among Hindus, and even Buddhism has its miracles. If you believe that miracles have occurred at any time in the past, then you cannot believe that natural causes are sufficient to account for all physical phenomena - and thus you cannot accept principle (h), which declares that they are. Thus if principle (h) is fundamental to science, then if you believe in miracles, you cannot practice science. This requirement would exclude the majority of the world's religious believers, some of whom were Nobel Prize winners, as we've seen. So much for the claim that methodological naturalism is religiously neutral.

Nor do the problems stop there. Textbook definitions of methodological naturalism [MN] usually emphasize that MN sidesteps questions relating to ultimate origins. As Paul de Vries puts it in his 1983 essay, "Naturalism in the Natural Sciences": "The original causes or ultimate sources of the patterns of nature are not proper concerns within any of the natural sciences." But if the epistemic definition of MN in principle (h) is the only definition which adequately grounds MN in a consistent manner, then the question of ultimate origins cannot be bracketed in this fashion. To be a consistent methodological naturalist, you must believe that science is fully capable of explaining physical phenomena - which means that you have to believe that science is capable of accounting for their origin as well. The majority of the world's religious believers, however, would hold that the world was created at some point in the past by God or some other supernatural Deity, without Whom the world would never have come into existence. If you accept principle (h), then you will have to abandon this belief as well.

By now, we are left only with religious believers who either accept that the world is eternal, or who hold that the laws of Nature explain how the cosmos could have popped into existence, without any need for a Creator. What's more, these religious believers must also hold that the Deity has never broken the laws of Nature, and that nothing exists within the natural world which science cannot fully account for. Only religious believers who accept all of these things can be methodological naturalists, on the epistemic definition of MN which I am proposing, in principle (h).

Thus I would maintain that a fully consistent version of methodological naturalism, while not overtly hostile to religion as such, has anti-religious implications, in that it would preclude a very large proportion of the world's religious adherents from practicing science.

Methodological naturalism Mark II: Is Professor Pennock's weaker version of methodological naturalism viable?

At this point, some "accommodationist" defenders of methodological naturalism might object that the definition I have proposed above is too strong. They may wish to put forward a weaker version of MN - let's call it methodological naturalism Mark II - which would make it true by default, on the grounds that scientists have no way of testing for supernatural causes, and have managed to account for physical phenomena perfectly well without positing them:

(i) Scientists need to test their hypotheses, and because (1) there is no way in principle of testing for supernatural causes, and (2) scientists have hitherto managed to fully explain physical phenomena purely in terms of natural causes, all talk of the supernatural is banished from science.

This version of methodological naturalism sits well with the arguments of Professor Robert T. Pennock, in his 2011 article, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), 177-206, DOI: 10.1007/s11229-009-9547-3), where he writes:

"My own account has been to explicate scientific naturalism as a methodological commitment, not an a priori metaphysical one, and to rationally reconstruct it as arising from a basic value in science, namely to the idea of testability or more precisely, to science's epistemic value commitment to the authority of empirical evidence. MN [Methodological naturalism] is not dogma; it continues to be accepted in part because of its success - it works. Moreover, we do not necessarily rule out modifying the ground rule if someone were to find a workable method of finding evidence for supernatural hypotheses. On my analysis of the relevant concepts I find it hard to even imagine what such an alternative method would look like and I have seen no proposal that comes close to being conceptually coherent (certainly IDCs [intelligent design creationists] do not have such a method) but I remain open to being show wrong." (p. 199)

"Would it even be intelligible to speak of supernatural "weight" or supernatural "color"? If these were truly meant to be different from the notions of weight and color as we understand these concepts in terms of our ordinary natural experience, then we have no ground upon which to draw any inference about them. Supernatural "design" is of a kind. As Hume pointed out, we have no experience and thus no knowledge of divine attributes. Those who think otherwise, whether in the service of proving or disproving the divine, invariably do so by illegitimately assuming naturalized notions of the key terms or other naturalized background assumptions." (p. 189)

However, I would argue that this weaker version of methodological naturalism is fatally flawed. I base my argument on Arthur C. Clarke's Third Law, which states that any sufficiently advanced technology is indistinguishable from magic. One corollary of this law is that any sufficiently advanced technology is indistinguishable from the activities of a supernatural Being. In other words, if a smart enough race of aliens were to visit us, they could perform amazing feats that would fool us into thinking they were gods.

Personally, I am inclined to think that Arthur C. Clarke's Third Law is wrong. I don't think any race of aliens could resurrect a corpse, for instance, and even if they attempted to fool us into thinking they'd done so by somehow making the corpse disappear and instantly replacing it with another body teleported from somewhere else, I think our scientists could probably devise a way to detect the switch. But let that pass. My point here is that Pennock is committed to upholding Arthur C. Clarke's Third Law. If he denies it, then he has to acknowledge that there is a way to distinguish the activities of a supernatural agent from those of natural agents - and that would destroy his whole case for excluding all talk of the supernatural from science - namely, that scientists have no way in principle of testing for supernatural agents.

But if there is no way to distinguish supernatural agents from advanced aliens, then the Pennockian principle (i) put forward above will have to be modified, as follows:

(j) Scientists need to test their hypotheses, and because (1) there is no way in principle of testing for the existence of very advanced intelligent beings (whether natural or supernatural), and (2) scientists have hitherto managed to fully explain physical phenomena without positing these beings, all talk of the activities of very advanced intelligent beings (whether natural or supernatural) is banished from science.

It should be clear that principle (j) is indefensible as a rule of scientific methodology. First, it violates the hallowed Copernican principle, beloved of anti-supernaturalists, which states that there is nothing special about our Earth and its place in the universe. This means that if intelligent life evolved on Earth, then we should expect it to have evolved on other Earth-like planets too. But some of these planets are billions of years older than our own, which means that by now, the intelligent life-forms on these planets would be light years ahead of us, in terms of their technology. If this is the case, then principle (j) is wrong, as it denies the legitimacy of even talking about such beings, on methodological grounds. Thus if Pennock wishes to uphold (j), he will have to abandon the Copernican principle.

Second, the claim in principle (j) that scientists have no way in principle of testing for the existence of very advanced intelligent beings is clearly false, as it would be easy for them to send us a signal which unambiguously confirmed their presence: the first 1,000 digits of pi, for instance. (The odds of 1,000 successive digits encoding the first 1,000 digits of pi by chance is 10^1,000, which is greater than the number of events, or operations, that have occurred in the history of the entire observable universe from the Big Bang up to the present - a number estimated by Seth Lloyd at 10^120 in his article, Computational capacity of the universe in Physical Review Letters 88:237901, 2002.) Scientists receiving a mathematical signal of this sort would automatically infer that it came from an advanced civilization. If the civilization then sent us further signals containing scientific information that was hitherto unknown to us, then scientists would know they were much more advanced than we are.

Since principle (j) contains a demonstrably claim, and since principle (j) is entailed by principle (i), it follows that principle (i), which I shall refer to as the Pennockian version of methodological naturalism, must be a flawed methodological principle.

Paul de Vries to the rescue?

Perhaps we can shed more light on the justification for methodological naturalism by re-examining Paul de Vries' original 1983 essay on "Naturalism in the Natural Sciences," which I cited above. Here is what de Vries writes about supernatural explanations (all citations below are taken from page 289 of de Vries' article):

I let go of my pencil and it immediately falls to the floor. Why? It would not be scientifically enlightening to say, "God made it that way." Similarly, scientists would not explain a particular rainstorm in terms of an Indian's rain dance or a farmer's prayers. Rainstorms are explained in terms of natural factors, such as air pressure and temperature — factors that themselves depend on other natural factors.

In this passage, de Vries rejects supernatural explanations as "not ... scientifically enlightening." However, the same objection could be made to the claim that a physical phenomenon - say, a monolith on the Moon - was produced by some unknown race of aliens who were far more technologically advanced than we are. Since the latter claim is generally acknowledged to be scientifically meaningful at least, there can be no a priori grounds for excluding the former.

But let us go along with de Vries' logic, for the sake of argument. Assuming he is right, what has he actually demonstrated? So far, all he has established is principle (f), which states that scientists should look for natural proximate causes when attempting to account for physical phenomena. We are still a long way from principle (g), which stipulates that scientists should confine themselves to natural causes, whether proximate or remote, when attempting to account for physical phenomena.

De Vries continues:

In brief, explanations in the natural sciences are given in terms of contingent, non-personal factors within the creation. If I put two charged electrodes in water, the hydrogen and oxygen will begin to separate. If I were writing a lab report (even at a Christian College!), it would be unacceptable to write that God stepped in and made these elements separate. A "God Hypothesis" is both unnecessary and out of place within natural scientific explanations.

Two points are pertinent here. First, de Vries fails to explain why a good scientific explanation has to be not only contingent but also impersonal. If there are other intelligent life-forms in outer space, then there must be some physical phenomena (i.e. alien artifacts) for which the proper scientific explanation is a personal one, appealing to the intentions of their makers. It would be puzzling if de Vries rejected such an explanation as unscientific.

Second, de Vries' rejection of the explanation that "God stepped in and made these elements separate" commits him to nothing more than principle (e), which states that scientists should avoid appealing to miracles, when attempting to account for physical phenomena, or alternatively, principle (f), which states that scientists should look for natural proximate causes when attempting to account for physical phenomena. It would preclude scientists appealing to God as an immediate cause of physical phenomena, but not as an ultimate cause. We are still nowhere near establishing principle (g).

But de Vries is not finished yet. He continues:

The naturalistic focus of the natural sciences is simply a matter of disciplinary method. It is certainly not that some scientists have discovered that God did not make phenomena occur the way they do. The original causes or ultimate sources of the patterns of nature are not proper concerns within any of the natural sciences — though they remain a wholesome and legitimate concern of many natural scientists. The natural sciences are limited by method to naturalistic foci. By method they must seek answers to their questions within nature, within the non-personal and contingent created order, and not anywhere else. Thus, the natural sciences are limited by what I call methodological naturalism.

In this paragraph, de Vries finally espouses principle (g), when he insists that "[t]he original causes or ultimate sources of the patterns of nature are not proper concerns within any of the natural sciences." He simply asserts this; he does not tell us why. However, since the complete explanation of any phenomenon requires tracing it back to its ultimate cause, then it seems that de Vries is committed to the claim that science does not aim to give complete explanations of phenomena. But if scientific explanations of phenomena may (for all we know) be incomplete, then the autonomy of science as a discipline can no longer be guaranteed, since we cannot exclude the possibility that the Creator and Ultimate Cause of natural phenomena might decide to alter their regular patterns of behavior at some date in the future, for reasons best known to Himself. On de Vries' proposed account of science, any variation in the regular patterns of nature would throw the whole of science into disarray.

The argument I have put forward here is that by excluding questions about ultimate explanations from the domain of science, de Vries has thrown into jeopardy the autonomy of science as a discipline - which was the very thing he wanted to uphold. We are forced to conclude, then, that de Vries' justification of methodological naturalism is insufficient, because it fails to preserve the autonomy of science from the domain of the supernatural.

Methodological naturalism Mark III: Will an even weaker version of methodological naturalism do the trick?

At this point, the reader may be wondering whether a defender of methodological naturalism might be better off dropping Pennock's testability criterion and relying solely on the success of science in explaining phenomena over the past 400 years, without invoking supernatural beings. In other words, perhaps we should define methodological naturalism as follows:

(k) Because scientists have hitherto managed to fully explain physical phenomena purely in terms of natural causes and without positing supernatural agents, all talk of the supernatural is banished from science.

I would like to point out that principle (k) is a very weak version of methodological naturalism, as it suggests that scientists would abandon the principle instantly, if they discovered a natural phenomenon that proved recalcitrant to naturalistic explanations.

The deficiencies in principle (k) should be readily apparent. Substitute any speculative scientific notion (e.g. magnetic monopoles) in place of "supernatural agents" and the flaw in the principle becomes obvious:

(l) Because scientists have hitherto managed to fully explain physical phenomena purely in terms of natural causes and without positing magnetic monopoles, all talk of magnetic monopoles is banished from science.

There are two obvious problems with such a principle. First, it's a non sequitur: the practical conclusion simply does not follow from the factual premise. Just because scientists have succeeded so far in explaining phenomena within the cosmos without resorting to entities such as monopoles (the existence of which has been hypothesized by some physicists), it does not follow that they shouldn't even talk about them.

Second, principle (l) (and any other principle like it) is far too dogmatic, as it would rule all new, unproven scientific concepts out of court on the sole grounds that scientists have never had to invoke them in the past, when they knew less than they do now. If principle (l) and others like it were taken seriously, science could never progress, as scientists could never even talk about, let alone test, new scientific concepts.

Since the weaker, Pennockian version of methodological naturalism in principle (i), which is based on the notion of testability, entails a demonstrably false principle (j), and since the even weaker principle (k), based on the success of science, fares even worse, I conclude that the only viable version of methodological naturalism is the strong version, formulated in principle (h) above - a version which, as we saw, runs afoul of the claims of many religions.

What's wrong with methodological naturalism, in a nutshell

It might still be objected that while I have refuted various versions of methodological naturalism, I have not yet provided any positive grounds for abandoning it. That is a fair criticism, which I would now like to remedy by putting forward the following syllogism.

1. One of the aims of science is to discover fully adequate explanations of physical phenomena.

2. For at least some physical phenomena, the only fully adequate explanation is one which appeals to intelligent agency. [Artifacts are an obvious example.] Any explanation of these phenomena which did not appeal to intelligent agency would be inadequate.

3. Scientists cannot know whether an explanation of a physical phenomenon is fully adequate unless they can ascertain whether the phenomenon in question is capable of being completely explained without invoking the notion of intelligent agency. (If the answer is negative, then any purported explanation of that phenomenon which ignores the notion of intelligent agency will be incomplete.)

4. There is no reason in principle why the universe - or the multiverse, for that matter - should be capable of being fully explained without invoking intelligent agency.

5. If the multiverse requires an explanation in terms of intelligent agency, then by definition, the Intelligent Agent Who explains the multiverse is supernatural.

6. By refusing to even consider the possibility that the multiverse may have a supernatural explanation, scientists are failing to properly carry out their scientific work, which is to look for fully adequate explanations of physical phenomena.

7. Hence, in order for scientists to do their work properly, science should remain methodologically open to the (epistemic) possibility that a supernatural Being exists, and that the postulation of this Being is required in order to fully explain physical phenomena.

The critical premises here are the first, second, fourth and fifth.

Premise 1: Is the explanation of physical phenomena one of the aims of science?

Someone who adopts Pierre Duhem's approach to science will find the first premise problematic. Duhem famously rejected the view that the aim of science was to explain physical phenomena, arguing that because explanations involve appeals to metaphysical concepts, and because scientist A and scientist B may have radically different views on matters relating to metaphysics, it would be impossible to ever secure agreement among scientists that a given explanation of phenomena was in fact the right one. Other alternatives would always suggest themselves. The sheer diversity of possible interpretations of quantum mechanics may appear to lend a certain plausibility to Duhem's argument.

In response, I would argue that:

(i) different explanations of physical phenomena have testable consequences, which means that it should be possible to eventually rule out some metaphysical concepts, if they entail conclusions which are at variance with the data;

(ii) the fact that there is such a variety of interpretations of quantum mechanics tells us nothing more than that the science is in its infancy;

(iii) as Alvin Plantinga points out in his essay, Methodological Naturalism?, a radical rejection of all metaphysical concepts would make belief in an external world and an objective past unscientific, which would mean that belief in common descent would be unscientific. If we defined science in this narrow fashion, it would mean that an evolutionist could not be a methodological naturalist!

Another question that might be asked is whether the first premise commits me to the view that science aims to discover the true explanations for physical phenomena. Some scientists contend that science should not be reagrded as the search for true explanations of phenomena, but rather, as the search for useful explanations that generate testable predictions which are fully in accord with the observed facts. As it happens, I support the former view, but the argument I am propounding here is neutral between the two views. All that matters for my purposes is my claim in premise (2), that for some physical phenomena (e.g. artifacts), scientific explanations which appeal to the notion of intelligent agency can explain facts about those phenomena which alternative explanations cannot.

Premise 2: Is the notion of intelligent agency indispensable for the scientific explanation of some physical phenomena?

Most people (including most scientists) would regard premise (2) as undeniably true. Forensics and archaeology are two obvious examples of scientific disciplines where the notion of intelligent agency comes into play. Indeed, premise (2) can only be denied by reductionists, who hold that explanations appealing to intelligent agency can always be replaced by lower-level explanations in which intelligent agency does not figure, or by eliminative materialists, who maintain that there are no such things as intentional acts, which means that all explanations which appeal to the beliefs, desires and intentions of intelligent agents are fundamentally misguided.

The point I wish to make here is that reductionism and eliminative materialism are both strong metaphysical positions. They are much stronger, for instance, than the more modest (and more widely held) version of materialism known as emergentist materialism, which readily grants that the beliefs, desires and intentions of intelligent agents are irreducible to underlying physical processes, but nevertheless insists that our mental acts supervene upon these physical processes. For an emergentist materialist, higher-level explanations of physical phenomena which appeal to the notion of intelligent agency are a legitimate part of the scientific endeavor, which cannot be replaced by lower-level explanations.

Thus someone who wishes to challenge my argument against methodological naturalism by rejecting premise (2) has to adopt a very radical metaphysical position, as well as committing him/herself to the odd view that all scientific explanations of physical phenomena which appeal to the notion of intelligent agency are ultimately dispensable. But the whole point of scientists adopting methodological naturalism, as opposed to metaphysical naturalism, is that it allows them to avoid committing themselves to controversial metaphysical positions. In other words, if a methodological naturalist were to question premise (2), he/she would be in effect acknowledging that to be a methodological naturalist, you have to be a metaphysical naturalist too, which defeats the whole purpose of methodological naturalism.

Premise 4: Is there any reason in principle why the multiverse should not require intelligent agency to explain it?

Premise (4) is a premise which could only be denied by a metaphysical naturalist who believed that the whole concept of a supernatural agent is absurd. The same comments apply here as for premise (2): if a methodological naturalist were to deny this premise, then he/she would be acknowledging that in order to be a methodological naturalist, one must be a metaphysical naturalist as well: a self-defeating position.

Premise 5: Does an Intelligent Agent who explains the multiverse need to be supernatural?

That leaves us with the fifth premise. Someone might query this premise, arguing that perhaps that which explains the multiverse is something outside Nature as we know it, but still governed by scientific laws of its own. We might call it "Nature 2," as opposed to our own multiverse (of which our universe is a tiny part), which is "Nature 1." If some intelligent agent who lives inside Nature 2 is capable of generating the laws and occurrences found in Nature 1, then we have no need to invoke a supernatural agent in order to explain the multiverse, after all.

The problem with this proposal is that if Nature 2 explains Nature 1, then it must somehow contain Nature 1 - and if it contains Nature 1, then the laws of Nature 1 are subsumed by the (more general) laws of Nature 2. (This is true regardless of whether the laws of Nature 1 are generated by a blind process occurring in Nature 2, or by an intelligent agent within Nature 2, who created Nature 1 as a simulation.) However, the term "multiverse", as I am using it here, simply refers to the largest domain of entities whose behavior is regulated by scientific laws. Hence if Nature 2 has laws of its own, Nature 1 is not the multiverse; Nature 2 is.

It follows that any intelligent agent who explains the multiverse (as I am using the term) is a Being Who is not bound by any laws at all. An intelligent agent who is not bound by laws can only be described as supernatural.

The conclusion I have argued for here is that there are strong prima facie grounds for regarding science as an open-ended enterprise which has no built-in methodological constraints on its search for fully adequate explanations of physical phenomena. In other words, there is no principled reason why science cannot take us to God, if by "God" we mean an infinitely wise Being.

The shifting grounds of support for methodological naturalism

The Creation of Adam, by Michelangelo. Sistine Chapel. 1510. Image courtesy of Wikipedia.

1. Supernaturalism in science would open the door to an infinite menagerie of supernatural beings

One facetious reason which is commonly given for keeping all talk of the supernatural out of science is that if we open the door to supernatural agents, there are an infinite number of possible candidates: a Deistic God who never tinkers with Nature; the God of classical theism, who is perfectly capable of doing so; the God of the Bible, who frequently does so; the God of Islam, who reveals Himself but disdains miracles; or for that matter, Krishna, Mazda, Zeus, Odin or even the Flying Spaghetti Monster. In reply, it might be urged that corporeal deities are, by definition, part of the physical order and hence not supernatural, but that still leaves us with a bewildering (and potentially infinite) variety of incorporeal candidates whose essential characteristics might differ, and whose attitudes and intentions may be diametrically opposed to one another. In which God should we trust?

The short answer to this question is: that shouldn't concern us too much. Even if scientists were able (at some future date) to conclusively establish that certain phenomena were caused by a supernatural Agent, but were utterly unable to say which one, that would still be an interesting scientific finding in its own right, which would be of immense significance for the human race - just as it would have been if the face on Mars had proved to be the work of some unknown extra-terrestrial intelligence.

The longer and more thoughtful answer is that the number of natural explanations for a newly observed phenomenon is also potentially infinite, and there is no way of testing all of them; nevertheless, scientists usually have little difficulty in practice in settling on a "best candidate" or a small, finite range of competing candidates. If scientists are able to eliminate a potentially infinite number of bad or defective natural explanations for a phenomenon, is there any good reason why they couldn't also eliminate a vast swath of second-rate supernatural explanations, on the methodological grounds that they were either too ad hoc or too vague? That would at least narrow the field.

Finally, there appears to be no reason in principle why scientists couldn't eventually arrive at a consensus on some of the essential characteristics of a supernatural Creator. For instance, the discovery of a structure in Nature that turned out to be capable of storing an indefinitely large (i.e. potentially infinite) amount of information would seem to indicate that its Creator had an (actually) infinite capacity to store and/or access information. (Only something with an actually infinite capacity is capable of generating something with a potentially infinite capacity.) One fruitful question for scientists to examine would be whether in fact the human brain (or for that matter, the brains of mammals and birds, who are probably conscious) has a potentially infinite capacity for storing information, or whether it has a built-in upper limit.

2. A supernatural being could wreak havoc with the cosmos, making it impossible for scientists to do their work

A second frequently heard objection to allowing supernaturalism in science is that a supernatural Deity, if it existed, would be capricious: such a Being could violate the laws of Nature at a moment's notice, without giving any warning, making it impossible for scientists to go about their everyday business. Now, for all scientists know, the law of gravity may fail to hold in five minutes' time. Epistemically, we cannot rule out this possibility, but on a practical level, we still conduct our lives in the assurance that the laws of Nature which have reliably held in the past will continue to hold in the future. However, if scientists became aware of some Being that was capable of interfering with the laws of Nature, which they rely on in their everyday work, they would be forced to entertain the real (as opposed to hypothetical) possibility that their experiments might or might not work. The continual distraction generated by the existence of a supernatural Agent would make it impossible, in practice, for scientists to go about their work. If we want scientists to concentrate on their research and avoid having to deal with metaphysical issues beyond their ken, then supernatural agents have to be excluded from the scientific worldview, as a matter of practical necessity.

I have to say that I find this objection disingenuous, as it glides over different senses of "capable." For instance, would a God who (as the nineteenth century mathematician and theologian Baden Powell envisaged) is by nature incapable of breaking his promises, and whose laws of Nature have the status of edicts (i.e. promises which even God cannot break), make it impossible for scientists to do their work? Obviously not. Researchers would have no problem with such a scientifically benign Deity. What about a God who promised not to violate the laws of Nature, except for the gravest of reasons, and only in ways that caused no harm to human life, and that left laboratory research intact? My guess is that scientists would rapidly adjust to this situation: after all, there's very little practical difference between an experiment that's known to work 99.999999% of the time and one that works 100% of the time. What about a supernatural Being Who is silent, and says nothing at all about His intentions? This situation would be a little disquieting at first, but in the end, scientists (like the rest of us) would have to learn to live with it. If enough time passed without any nasty "incidents", then scientists would eventually conclude that the Being in question posed no threat to science, and go back to their research.

3. Supernaturalism is a science-stopper

A third objection to allowing supernaturalism in science is that it is a science-stopper. Michael Ruse makes this argument in a recent article for The Guardian (5 May 2010) entitled, Intelligent design is an oxymoron, where he wrote:

...[A]lthough ID is not bad science – it is not science at all – its intent is deeply corrosive of real science. As Thomas Kuhn pointed out repeatedly, when scientists cannot find solutions, they don't blame the world. They blame themselves. You don't give up in the face of disappointments. You try again. Imagine if Watson and Crick had thrown in the towel when their first model of the DNA molecule proved fallacious. The very essence of ID is admitting defeat and invoking inexplicable miracles. The bacterial flagellum is complex. Turn to God! The blood clotting cascade is long and involved. Turn to God! That is simply not the way to do science.

What I find most astonishing about Ruse's argument here is that it was fully answered by someone whom he quoted in his article: William Whewell (1794-1866), who in his 1833 work, Astronomy and general physics. Considered with reference to natural theology (New York, Bairper and Brothers, 1856), turned the tables on his atheistic opponents by charging them with being science-stoppers for failing to ask why the universe existed:

It is related of Epicurus that when a boy, reading with his preceptor these verses of Hesiod, thus translated: "Eldest of beings, Chaos first arose, Thence Earth wide stretched, steadfast seat of all The Immortals," the young scholar first betrayed his inquisitive genius by asking "And chaos whence?" When in his riper years he had persuaded himself that this question was sufficiently answered by saying that chaos arose from the concourse of atoms, it is strange that the same inquisitive spirit did not again suggest the question "and atoms whence?" And it is clear that however often the question "whence?" had been answered, it would still start up as at first. Nor could it suffice as an answer to say, that earth, chaos, atoms, were portions of a series of changes which went back to eternity. The preceptor of Epicurus informed him, that to be satisfied on the subject of his inquiry, he must have recourse to the philosophers. If the young speculator had been told that chaos (if chaos indeed preceded the present order) was produced,by an Eternal Being, in whom resided purpose and will, he would have received a suggestion which, duly matured by subsequent contemplation, might have led him to a philosophy far more satisfactory than the material scheme can ever be to one who looks, either abroad into the universe, or within into his own bosom. (1833, pp. 133-134)

In Whewell's view, the real "science-stopper" is not supernaturalism but the premature introduction of final causes into science: once we know why something exists, there is a temptation to stop asking further questions about it. Hence he insists that scientists should endeavor to identify the physical causes of natural phenomena, tracing them as far back as they can possibly go, before inferring the existence of a Creator of the natural world. Then and only then are scientists in a position which allows them to see the end or purpose of the natural phenomena that they are investigating:

Final causes are to be excluded from physical inquiry; that is, we are not to assume that we know the objects of the Creator's design, and put this asssumed purpose in the place of a physical cause. We are not to think it a sufficient account of the clouds that they are for watering the earth, (to take Bacon's examples,) or "that the solidness of the earth is for the station and mansion of living creatures." The physical philosopher has it for his business to trace clouds to the laws of evaporation and condensation; to determine the magnitude and mode of action of the forces of cohesion and crystallization by which the materials of the earth are made solid and firm. This he does, making no use of the notion of final causes: and it is precisely because he has thus established his theories independently of any assumption of an end, that the end, when after all, it returns upon him and cannot be evaded, becomes an irresistible evidence of an intelligent legislator. He finds that the effects, of which the use is obvious, are produced by most simple and comprehensive laws; and when he has obtained this view, he is struck by the beauty of the means, by the refined and skilful manner in which the useful effects are brought about; — points different from those to which his researches were directed. (1833, p. 219)

In an essay entitled, , philosopher Paul Herrick puts forward a principle of inquiry which he calls the Daring Inquiry Principle (DIP):

When confronted with the existence of some unexplained phenomenon X, it is reasonable to seek an explanation for X if we can coherently conceive of a state of affairs in which it would not be the case that X exists.

This is an open-ended principle of inquiry, unlike the one he attributes to atheist philosopher Keith Parsons, and which he humorously dubs the Principle of Parsony:

In general, the nonexistence of X is no mystery unless, given general background knowledge, its existence is either expected or is no more unexpected than what does exist (i.e., its existence is at least as expected as that which does exist).

The Principle of Parsony tends to make people incurious about "brute facts". For instance, Professor Parsons concludes that we have no rational basis for expecting that some other universe might have existed instead of ours, or that there might have been nothing at all, just as we have no basis for expecting that the moon might have been made of green cheese. The existence of an ex-hypothesi eternal universe, therefore, is no more of a mystery than the nonexistence of a moon made of green cheese.

In a post of mine, entitled, Why the moon isn’t made of green cheese (Part One of a reply to Professor Keith Parsons) I argued that there was in fact a reasonable answer to the question, "Why isn't the moon made of green cheese?", which even a young child can understand:

So, how would I answer a young child's question: "Why isn't the moon made of green cheese?" If the child was about five years old, I'd answer it like this. To make cheese, you need milk. The only way you can make milk naturally is from animals like cows, who feed their babies with it. There are no animals on the moon, and there never have been. Animals need air, and the moon doesn’t have any, because it's too small to keep its air. So there's no way of naturally making a moon out of cheese, let alone green cheese. The key notion being deployed here is that certain raw materials (e.g. milk, from which cheese is made) have a characteristic natural origin: they originate in this way, and no other.

If the child was aged eight years or older, I would add that scientists believed that all of the matter in the universe was originally a very light gas called hydrogen, and that over the course of time, other heavier elements formed, such as iron. Carbon (found in the proteins contained in cheese) formed too, but it was just one of many elements. So even if cheese could form naturally from the elements, without the need for animals, it would be very unlikely that the moon would contain nothing but cheese – a bit like flipping a million coins and getting nothing but heads. At this level, the answer to the child's question, "Why isn't the moon made of green cheese?" invokes a rudimentary notion of probability.

If the child were ten years or older, I would further add that the most popular scientific theory of the moon's origin is that it was formed from the debris left over when another planet collided with Earth. To encourage the child to keep an open mind, I would also mention that some scientists are proposing a new theory of the moon’s formation, according to which a massive nuclear explosion occurred at the edge of Earth’s core, flinging red-hot, liquid rock into space. The orbiting debris gradually coalesced into what is now our moon. No matter which theory is correct, however, the logic is the same: since the Earth isn’t made of green cheese, we wouldn’t expect the moon to be. So the answer to the child’s question in this case depends on the added piece of information that the Earth materially contributed to the moon’s formation.

two arguments put forward by Herrick, showing why the Principle of Parsony is a very poor explanatory principle, because it’s a science-stopper.

First, the Principle of Parsony would rule out a lot of questions that most scientists would consider perfectly reasonable to ask. Here’s one example proposed by Professor Herrick:

One day in the physics lab, Susan, an undergraduate, overhears some grad students talking about the charm quark, c, and the fact that it has a 2/3 charge. Knowing nothing about quarks except that they are particles inside protons and neutrons, she asks: "Why does the charm quark have a 2/3 charge (rather than no charge at all, or rather than some other charge)?" Common sense suggests that Susan’s question is a perfectly reasonable one, even if (to paraphrase Parsons) nothing in her knowledge base supports the slightest quantitative expectation that the charge of the charm quark would be some other number… In other words, it seems to me that Susan's question is legitimate without the basis of expectations required by the principle of Parsony.

No-one has ever seen a charm quark with a charge of 1/2, and if we were to base our expectations purely on "physical antecedents and laws of nature," as Professor Parsons would have us do, then we’d never have the slightest reason to expect a charm quark to have a charge of 1/2. Nevertheless, the question, "Why does the charm quark have a 2/3 charge rather than a charge of 1/2?" is a legitimate one for physicists to ask. A principle of inquiry that rules out questions like that deserves to be called a science-stopper.

Herrick's second and more powerful argument against the Principle of Parsony is that "physical antecedents and laws of nature cannot be the only legitimate grounds for the types of expectations allegedly governed by POP" because if they were, the scientific enterprise would never have gotten started in the first place. Thus the Principle of Parsony (POP), in its physicalist version, is “self-referentially incoherent: it presupposes that we possess a particular type of knowledge, while at the same time making it impossible that we ever attain that type of knowledge in the first place.” To illustrate his point, Herrick invites us to consider the individuals who discovered the very first scientific law ever formulated:

Consider the exact moment just before the first instance of coming to know a physical antecedent or a law of nature. At that moment, we would not know any physical antecedents or laws of nature. But then (according to POP) we could not ask questions such as "Why does this rather than that happen?" and "Why does this rather than that exist?"

Professor Herrick then administers his coup de grace to the Principle of Parsony:

Yet questions of this type are surely necessary for any scientific investigation of the world, including the discovery of the very physical laws of nature and physical antecedents required by POP. In other words, at the beginning of all empirical investigation, lacking the basis of expectations required by the physicalist interpretation of POP – knowledge of physical antecedents and laws of nature – we could not legitimately ask the sorts of questions that must be asked if we are to pursue and attain the empirical knowledge presupposed by the physicalist interpretation of POP… The physicalist interpretation of POP cannot be right if we have any empirical knowledge at all.

If we adopt Professor Parsons' physicalist interpretation of POP, and base our expectations on physical antecedents and laws of nature, then it appears to be the ultimate science-stopper: it prevents scientific inquiry from ever getting started!

4. Methodological naturalism is true by definition: it's the way science is done

A fourth argument for disallowing talk of the supernatural in science is that that's the way science is done, period. In the words of philosopher of science Michael Ruse:

The Creationists believe that the world started miraculously. But miracles lie outside of science, which by definition deals only with the natural, the repeatable, that which is governed by law. (Darwinism Defended, Reading, Massachusetts: Addison-Wesley, 1982; p. 322.)

The obvious reply to Ruse is that the principle that science does not deal in miracles (or principle (e) in my list above) does not entail methodological naturalism: scientific explanations at a proximate level might be entirely natural; but at the ultimate level of scientific explanation, a supernatural explanation might still be required.

A better articulation of this argument was given by the late philosopher of science, Professor Ernan McMullin (1924-2011), when he wrote:

But, of course, methodological naturalism does not restrict our study of nature; it just lays down which sort of study qualifies as scientific. If someone wants to pursue another approach to nature--and there are many others--the methodological naturalist has no reason to object. Scientists have to proceed in this way; the methodology of natural science gives no purchase on the claim that a particular event or type of event is to be explained by invoking God's creative action directly.
("Plantinga's Defense of Special Creation" in Christian Scholar's Review, 1991, vol. 21, no. 1, pp. 55-70.)

My response to McMullin's claim that "scientists have to proceed in this way" is that it is simply an assertion without justification. What's more, it is a false one. The one thing - indeed, the only thing - that scientists have to do is explain natural phenomena. It is an open question whether the explanation of natural phenomena requires a Deity or not. Nothing in scientific methodology should prejudice that enquiry.

5. Methodological naturalism is entrenched scientific practice

A fifth argument for disallowing talk of the supernatural in science is that methodological naturalism is so deeply entrenched as a scientific practice that it would be impossible to even consider abandoning it. As Professor Robert Pennock puts it in his 2011 essay, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), pp. 177-206, DOI: 10.1007/s11229-009-9547-3):

"Put simply, the argument was that as a point of method science does not countenance appeals to the supernatural. Again, we did not claim that only science requires this ground rule. Such appeals are disallowed in court as well, for instance; MN [methodological naturalism] is tacitly assumed in legal reasoning just as it is in science and should be so for the same sorts of reasons (Pennock 1999, pp. 294-300). Suffice to say that no judge would take seriously a plaintiff who sought damages against someone for laying a curse upon their car or a defendant who pleaded innocent on the grounds that the crime had actually been committed by a ghost. A lawyer would be laughed out of court who argued that judges and juries should consider "alternative theories" that a crime was committed by a supernatural intelligence. The IDC's [intelligent design creationist's] call for a theistic science is similarly unworkable (Pennock 1998)." (2011, p. 185)

"Equally importantly, especially in the context of the case, even creationists grant that naturalism is a ground rule of science (though they typically confuse or conflate metaphysical and methodological naturalism). One of the reasons I advocated focusing on MN in the Kitzmiller case rather than other characteristic scientific values was that all of the major ID creationists had explicitly acknowledged it as a ground rule of science - though a ground rule they think should be overturned - often using those very words." (2011, p. 186)

"This is not like the umpire calling a player out who attempts a dusty slide to home plate but more like distinguishing a real ball game at Fenway Park from the "baseball movie" Field of Dreams.... ID does not just miss the line by a hair; the rational judgement here is that creationism does not even belong in the stadium, that it is playing a different game entirely - Sudoku perhaps. We do not need to delimit the boundaries of science any more than we need the precise boundaries of a pin to conclude that it is not science to debate how many angels can dance on its head. Fortunately a wise judge understood that even if a few myopic philosophers still do not." (p. 203)

I'd like to make six points in reply:

1. Although it would be correct to say that methodological naturalism is entrenched scientific practice, it has only been entrenched for the past 110 years, as I shall document below and in Part Six: it did not become generally accepted in the scientific community until around 1874, and even as recently as 1903, it was still being flouted by scientists of the stature of Lord Kelvin. Thus methodological naturalism is of comparatively recent origin as a rule of science.

2. "Is" does not imply "ought" or "must." The fact that methodological naturalism currently is entrenched scientific practice does not mean that it should be. Nor does it imply that the practice cannot be overturned. In fact, it has been overturned before, in the mid-nineteenth century. There is no reason why such a reversal cannot happen again.

3. There was a time when supernaturalism was a deeply entrenched scientific practice. Allow me to quote from the final paragraph of an essay by the late Professor Margaret Osler (1947-2010), a former Professor of history at the University of Calgary, in Galileo Goes to Jail and Other Myths about Science and Religion, edited by Ronald Numbers (Harvard University Press, 2009):

Seventeenth century natural philosophers were not modern scientists. Their exploration of the natural world was not cut off from their religious views and theological assumptions. That separation came later. Reading the past from the standpoint of recent developments has led to serious misunderstandings of the Scientific Revolution. For many of the natural philosophers of the seventeenth century, science and religion – or better, natural philosophy and theology – were inseparable, part and parcel of the endeavor to understand our world. (Osler, "Myth 10: Science and Religion in the Scientific Revolution," in Numbers, 2009, p. 98.)

It would obviously be absurd to argue that Galileo and Newton - both of whom violated methodological naturalism, as I shall demonstrate below and in Part Six - were not scientists, and of course, Osler does not do this. Instead, she declares that these seventeenth century natural philosophers were not modern scientists. She acknowledges that these men practiced science, but not science as we know it today: for these natural philosophers, science was intimately bound up with religion. The modern Intelligent Design movement believes that religious revelations have no place in science, but nevertheless argues that science should remain open to the existence of a supernatural Being or beings.

4. If science which allows talk of the supernatural is as different from science which disallows it as baseball is from Sudoku (to use Pennock's analogy), then why do we not find a clear dividing line between the two versions of science in history? Instead, what we find is that in the mid-nineteenth century, there were scientists who espoused methodological naturalism, and others who openly flouted it. Despite their radically different visions of what science should be, neither group accused the other of not doing science, however.

5. Pennock's legal reasoning is flawed. I don't know whether he has read Dean Koontz's 1983 novel, Phantoms. At the beginning of the story, Jenny and Lisa Paige, two sisters, return to Jenny's hometown of Snowfield, California, a small ski resort village nestled in the Sierra-Nevada Mountains where Jenny works as a doctor, and find no one alive. The few bodies they find are either mutilated, or reveal some strange form of death. The victims' faces are frozen in an expression of terror. Let us suppose for argument's sake that all the victims had died at the exact same time: eleven o'clock. Faced with such a discovery, I submit that the hypothesis that the people had all been killed by a malevolent supernatural agent would not be an unreasonable one, although there would be other explanations as well (e.g. a mass murder committed by evil aliens).

6. Pennock's slighting comparison of Intelligent Design theorists to medieval theologians debating how many angels could dance on the head of a pin (a topic which medieval theologians never actually debated, as Pennock should know) is based on a flawed analogy. Intelligent Design theory is the search for patterns in Nature which bear hallmarks of having been designed. Angels on the other hand are spirits, and hence not physical beings. They are not part of Nature as I have defined it. Questions about angels could therefore never be part of science.

6. The argument from success: naturalism has worked in the past

A sixth argument for ditching all talk of the supernatural in science is one which Phillip Johnson, an outspoken critic of methodological naturalism, refers to as the "argument from success" in his book, Reason in the Balance (1995, InterVarsity Press). In short: the modern scientific method, which posits only natural causes and shuns any invocation of the supernatural, has worked spectacularly well in the past, and has enabled human beings to unlock many of Nature's secrets and thereby gain better control over their environment. There is no reason to suppose that this method will fail us in the future. Based on the past success of science, it is reasonable to believing that remaining scientific mysteries such as the nature of dark matter and dark energy, the origin of life and of complex organisms, and the origin of consciousness, will eventually prove tractable to science. As Professor Lawrence Lerner memorably put it in a short piece entitled, Methodological Naturalism vs Ontological or Philosophical Naturalism, which was excerpted from a longer article he published for the NCSE (February 14, 2003), entitled, Proposed West Virginia Science Standards: Evaluated by Lawrence Lerner, Attacked by Intelligent Design Creationists:

Methodological naturalism is not a "doctrine" but an essential aspect of the methodology of science, the study of the natural universe... The spectacular successes over four centuries of science based on methodological naturalism cannot be gainsaid.

Professor Robert Pennock puts forward the same argument, albeit less stridently, in his 2011 article, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), pp. 177-206, DOI: 10.1007/s11229-009-9547-3), where he writes that "MN [Methodological naturalism] is not dogma; it continues to be accepted in part because of its success - it works" (p. 199).

The argument from success is open to criticism on philosophical grounds. First, it is an inductive argument, and if (like myself) you don't believe inductive arguments are valid in the absence of a supernatural Deity, then you won't find this one convincing, as it rejects the supernatural. Briefly: inductive arguments seem rational to us, because of our human preference for simple hypotheses: faced with a natural phenomenon that has recurred in the past, the simplest thing is to suppose that it will do so in the future. Nature, however, cares not one whit for our preferences, and there are an infinite number of alternative hypotheses we could posit that are perfectly compatible with the past regularities we've observed, but which posit some irregular occurrence in the future. One could posit that the Sun will keep rising in the future; but it might instead keep rising until the year 2400 and then turn into a green dragon, or keep rising at the sppointed time until 2300 and then quicken its tempo, rising once overy twelve hours instead of every twenty-four or so - and so on. What's more, every sunrise we've observed to date confirms not only our naive hypothesis that the sun will continue to rise in the future, but a vast number of alternative exotic hypotheses like the ones I've sketched as well. If Nature is godless, then we really have no way of knowing how it will behave in the future. Only if Nature is the manifestation of a trustworthy Intelligent Being who generally behaves in a regular, predictable fashion can we rationally infer that the suun will rise tomorrow.

In any case, the "argument from success" is not, strictly speaking, an inductive argument but a meta-inductive one. The scientists who propound this argument are arguing that because the process of induction has succeeded in the past, therefore induction will continue to work in science in the future.

Moreover, the data set for this meta-inductive argument is very small on a temporal scale. We are supposed to believe that because the scientific method has led to spectacular discoveries during the last few hundred years, therefore it will continue to be valid forever. Sorry, but that's not rational. That's wishful thinking.

Finally, the argument presupposes that science is closing the gaps in our knowledge. But the truth is that it is creating new gaps as fast as it plugs old ones. To cite but two: (1) In the Middle Ages, the best science supported the view that the universe had no beginning. Now we know that not only the observable universe, but the entire multiverse, must have had a beginning - a fact that we cannot explain without positing a supernatural Creator. (2) Abiogenesis was not a problem for people living in the Middle Ages: in fact, they took it for granted. Everyone believed in spontaneous generation. Today, however, it is a huge problem for scientists - and it's one which science has created, as we learn that life only comes from life, leaving unanswered the question: where did the first living cells come from?

7. The only possible arguments for supernatural beings are "God-of-the-gaps" arguments, which are invalid

A seventh argument for excluding supernatural beings from the domain of science is that the "God-of-the-gaps"-style arguments put forward for the reality of such beings are demonstrably invalid. As Professor Steven Schafersman puts it in his 1996 essay, Naturalism is Today An Essential Part of Science (presented at the Conference on Naturalism, Theism and the Scientific Enterprise) that :

Simple lack of knowledge for some natural process or event is not sufficient to justify a supernatural explanation. Frankly, I consider these god-of-the-gaps creationist arguments to be unworthy of modern analysis. So the use of natural evidence and arguments to demonstrate the existence of the supernatural is not sound.

The esteemed Christian philosopher Alvin Plantinga also has little time for "God-of-the-gaps" arguments either, but he draws a very different conclusion from Schafersman puts it in his essay, Methodological Naturalism?:

The following, therefore, are the essential points of God-of-the-gaps theology. First, the world is a vast machine that is almost entirely self-sufficient; divine activity in nature is limited to those phenomena for which there is no scientific, i.e., mechanical and naturalistic explanation. Second, the existence of God is a kind of large-scale hypothesis postulated to explain what can't be explained otherwise, i.e., naturalistically. Third, there is the apologetic emphasis: the best or one of the best reasons for believing that there is such a person as God is the fact that there are phenomena that natural science cannot (so far) explain naturalistically...

Newton's suggestion that God periodically adjusts the orbits of the planets is often cited as just such an example of God-of-the-gaps theology...

Serious Christians should indeed resolutely reject this way of thinking. The Christian community knows that God is constantly active in his creation, that natural laws, if there are any, are not independent of God, and that the existence of God is certainly not a hypothesis designed to explain what science can't. Furthermore, the Christian community begins the scientific enterprise already believing in God; it doesn't (or at any rate needn't) engage in it for apologetic reasons, either with respect to itself or with respect to non-Christians. But of course from these things it doesn't follow for an instant that the Christian scientific community should endorse methodological naturalism.

I entirely agree with Professor Schafersman that arguments from ignorance can never serve to establish the reality of a supernatural Being, but that's not how Intelligent Design proponents argue. Typically, they argue that any pattern occurring in Nature that exhibits a feature - such as a high degree of specified complexity - which is reliably associated with intelligent agency and which no unintelligent cause has ever been known to bring about, despite repeated attempts to find examples - should be regarded as the work of an intelligent agent. That's not an argument from ignorance.

And if the whole of the natural order were to exhibit such a feature, then the conclusion would likewise follow that Nature was the work of an intelligent agent - Who could only be supernatural.

http://cybercomputing.com/freeinquiry/files/naturalism.html

8. Allowing supernaturalism in science violates the integrity of Nature - which no true Deity would ever do

A eighth objection to allowing supernaturalism in science is that doing so would mean that God violates the functional integrity of Nature, which is something that no Deity worthy of the name would do.

According to physicist (and former Calvinist) Howard van Till, God has created a world characterized by "functional integrity":

By this term I mean to denote a created world that has no functional deficiencies, no gaps in its economy of the sort that would require God to act immediately, temporarily assuming the role of creature to perform functions within the economy of the created world that other creatures have not been equipped to perform.
("When Faith and Reason Cooperate", Christian Scholar's Review (Sept. 1991) p. 42.)

In reply: a world which requires Divine "intervention" - or rather, "manipulation," to use a less loaded word - is not a deficient world, but a limited one. To illustrate this point, ask yourself whether God could design a world in which "what goes around, comes around" - that is, a world in which humans possess libertarian free will, and in which virtue is invariably rewarded and evil is invariably punished by the forces of Nature, without the need for God to ever step in. Most of us, on reflection, would agree that designing a world like that would be impossible even for a Deity, given the potentially infinite variety of choices that a libertarian agent could make. If you happen to believe that virtue is ultimately rewarded, then you will need to posit a Last Judgement, or something along those lines. Likewise, it might simply be impossible for God to design a world in which evolution invariably leads to the production of intelligent beings, after a specified period of time - which would mean that if God wants to guarantee this result, then He may have to "step in" and guide evolution. The reader may object that God could accomplish this end by designing a deterministic universe and then fine-tuning its initial conditions extraordinary degree. Unfortunately, even that won't work, in a cosmos where space and time are quantized: the amount of information that would need to be input the desired result would exceed the storage capacity of the cosmos!

Physicist Rob Sheldon explains why front-loading won't work in his article, The Front-Loading Fiction (July 1, 2009):

Historically, the argument for front-loading came from Laplacian determinism based on a Newtonian or mechanical universe -- if one could control all the initial conditions, then the outcome was predetermined. First quantum mechanics, and then chaos-theory has basically destroyed it, since no amount of precision can control the outcome far in the future. (The exponential nature of the precision required to predetermine the outcome exceeds the information storage of the medium.)

But "front-loading" permitted Deists to say that God designed the Universe, and then stepped back and let "natural" forces operate, thereby removing any "supernatural" interference of the sort that Lucretius fumed about in 50 BC. So if Newtonian determinism was now impossible, perhaps there could be some sort of algorithmic determinism (which I'll call Turing determinism) which could step in and permit a Deist to avoid the supernatural. That is, God doesn't have to create the oak from the acorn anymore, but the biological program He inserted in the acorn can handle all the intermediate steps. So perhaps, God didn't have to create humans, but the biological program in the first living cell He created, started the ecosystem that eventually evolved humans...

Ian Turing himself addressed a number of algorithmic dilemmas with the thought experiment of the deterministic computer now called a Turing machine. He asked if the outcome of such a computer can always be predicted, and demonstrated several examples of completely unpredictable behavior. Applying this to our biological example, it says that some organisms may act/evolve unpredictably, though perhaps not the ones God programmed.

But Turing went beyond this existence proof, and demonstrated necessity -- a computing machine with feedback, where the output tape went into the input, was always unpredictable. In our biological example, we have to define the input and the output. TE [theistic evolution] tells us that the input is an organism, and the output is more organisms, and the computer is the organism too. In other words, the type of algorithmic determinism required by TE is not weakly, but strongly recursive, and therefore doubly unpredictable.

Even should God have infinite knowledge of the outcome of such a biological algorithm, the information regarding its outcome cannot be contained within the system itself. Therefore if the system is determined, it must be determined externally, with constraints outside of biology, which is exactly the definition of the supernatural that the TE "front-loading" was intended to remove!

Recently, van Till has gone even further in his arguing for the inappropriacy of supernatural "intervention": in an essay published in The nature of Nature (2011), he argues that any Divine manipulation of Nature is coercive:

Supernaturalism is but one form of theism among many. By "supernaturalism" I mean the specific form of theism (among North Americans it is perhaps the most common form) that entails a commitment to the belief that God is both able and, on occasion, willing to act coercively in the sense of exercising unilateral power over nature. Coercive divine action is a determinative form of divine action that supersedes natural action and brings about outcomes in the world that are either beyond or contrary to the capabilities of natural action. Form-imposing interventions, of the sort discussed above, would clearly fall into the category of coercive divine action. Defining naturalism as anti-supernaturalism may be somewhat unconventional, but I have come to appreciate the fruitfulness of this approach in my own reflections on the issues at hand. Most importantly, I believe, it provides the basis for dispelling the rhetorically popular but logically mistaken notion that all forms of naturalism are enemies of all forms of theism.
("Cosmic Evolution, Naturalism and Divine Creativity, or Who Owns the Robust Formational Economy Principle?", in Bruce L. Gordon and William A. Dembski, Nature of Nature: Examining the Role of Naturalism in Science. Wilmington, DE: ISI Books, 2011, p. 539.)

Van Till's argument illicitly assumes that God's unilateral power over Nature is inherently coercive. This is absurd: by definition, God cannot coerce what He has created for Himself. "The earth is the Lord's, and the fulness thereof; the world, and they that dwell therein" (Psalm 24:1, KJV). The world belongs to God; He has every right to do with it as he pleases.

If manipulating Nature necessarily involved God breaking the laws of Nature, then there is indeed a sense in which it might be regarded as "unnatural" and hence, coercive, from the perspective of creatures. However, it is quite possible for God to manipulate events at the subatomic level to bring about a desired outcome, without violating any laws. Where, I have to ask, is the coercion in this?

Theologian John Stek has argued, however, that even subatomic manipulation of Nature is unworthy of the Deity:

Since the created realm is replete with its own economy that is neither incomplete (God is not a component within it) nor defective, in our understanding of the economy of that realm so as to exercise our stewardship over it -- understanding based on both practical experience and scientific endeavors -- we must methodologically exclude all notions of immediate divine causality. As stewards of the creation, we must methodologically honor the principle that creation interprets creation; indeed, we must honor that principle as "religiously" as the theologian must honor the principle that "Scripture interprets Scripture" -- or, since Scripture presupposes general revelation, that revelation interprets revelation. In pursuit of a stewardly understanding of the creation, we may not introduce a "God of the gaps," not even in the as-yet mysterious realm of subatomic particles. We may not do so (1) because God is not an internal component within the economy of the created realm, and (2) because to do so would be to presume to exercise power over God -- the presumptuous folly of those in many cultures who have claimed to be specialists in the manipulation of divine powers (e.g., shamans in Russian folk religion and medicine men in primitive cultures).
("What says the Scriptures?" in Howard J. Van Till, Robert E. Snow, John H. Stek, and Davis A. Young, Portraits of Creation: Biblical and Scientific Perspectives on the World's Formation (Grand Rapids: Eerdman's Publishing Co., 1990) p. 261.)

Stek's prolix argument is marred by a bewildering lack of clarity. He refers to "the principle that creation interprets creation." What principle is this, pray tell? Since when did it become binding, and why?

Stek also argues that "God is not an internal component within the economy of the created realm." Certainly, but why does manipulating the create realm for His own ends make God "an internal component within the economy of the created realm" (emphasis mine)?

Finally, as for Stek's argument that such beliefs lead to "manipulation of divine powers" by human beings, I have to say that this is a complete non sequitur. If a scientist invokes a "God of the gaps," that does not mean that he/she must "presume to exercise power over God." Rather, it means that the scientist believes that at some point in the past, God exercised extraordinary power over Nature.

9. The reality of supernatural beings is impossible in principle to verify

An ninth objection to allowing supernaturalism in science comes from John C. Wilkins' 1997 article, Evolution and Philosophy - Naturalism: Is it necessary?. He writes:

The usual way to define non-natural is that it is not explicable in terms of natural laws; that is, it breaks the causal chain. If we abandon the methodological assumption of naturalism - that everything is open to empirical investigation - we can say that anything not presently explained by scientific laws is non-natural, but that's not what is meant. We can distinguish between our present ignorance and something that's in-principle not scientifically explicable, surely. We want something that is completely outside the course of physical events [some proponents of the term 'supernatural' use it to mean 'uncaused' - what that actually means is really unclear].

But if we had it, could we incorporate it into a scientific explanation? We could obviously not use empirical observations - they depend on the ordinary course of physical processes. So what else is there? The answer is, nothing. Non-natural explanations are not scientific.

In a similar vein, Professor Steven Schafersman contends in his 1996 essay, Naturalism is Today An Essential Part of Science (presented at the Conference on Naturalism, Theism and the Scientific Enterprise) that :

There is no way for supernaturalists to establish the truth of an intelligent design hypothesis using the methods of science. I maintain that it is impossible, in principle, for natural evidence and arguments to demonstrate the existence of anything supernatural, such as creation, intelligent design, or a god. In order to demonstrate the reality of such supernatural processes or entities in this way, one would have to know the relationships or interactions between the natural and supernatural, and we don't know these.

Robert Pennock makes the same point in his 2011 essay, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), 177-206. DOI: 10.1007/s11229-009-9547-3), when he writes:

"Would it even be intelligible to speak of supernatural "weight" or supernatural "color"? If these were truly meant to be different from the notions of weight and color as we understand these concepts in terms of our ordinary natural experience, then we have no ground upon which to draw any inference about them. Supernatural "design" is of a kind. As Hume pointed out, we have no experience and thus no knowledge of divine attributes. Those who think otherwise, whether in the service of proving or disproving the divine, invariably do so by illegitimately assuming naturalized notions of the key terms or other naturalized background assumptions." (p. 189)

Both of these criticisms are mis-directed, because they presuppose an over-simplistic model of how science works. Wilkins maintains that before something can be incorporated into a scientific explanation, "empirical observations" are required. What kind of observations is he talking about? Perhaps he means empirical observations of the thing itself, which would enable scientists to see precisely how it causes its effects - in other words, which empirical properties of the thing consistently change whenever it produces the effect. But this requirement makes sense only if scientific explanations have to always proceed by way of an inductive inference, from repeated observations to a general explanatory statement. Such a position rests upon a rather naive view of how science works.

There is an alternative interpretation: maybe Wilkins and Schafersman are assuming a hypothetical-deductive model of scientific inference. In that case, observations are required to verify predictions of how the causal agent should act under certain circumstances. This would also explain Schafersman's remarks about the need for an understanding of the relationship between natural and supernatural.

But this too is inadequate. Scientific explanations aren't always hypothetical-deductive, and neither are they always inductive. Often, Scientific explanations are abductive.

10. Naturalism is impossible in principle to falsify

A tenth objection to allowing supernaturalism in science comes from Professor Steven Schafersman, an American geologist and current President of Texas Citizens for Science. In the 1997 version of his 1996 essay, Naturalism is an Essential Part of Science and Critical Enquiry, Schafersman argues that naturalism is unfalsifiable even in principle, citing the well-known argument against miracles, put forward by the Scottish philosopher David Hume (1711-1776), in his chapter "Of Miracles" in An Inquiry Concerning Human Understanding (1748).

"...no testimony is sufficient to establish a miracle, unless the testimony be of such a kind, that its falsehood would be more miraculous, than the fact, which it endeavors to establish..."

Professor Schafersman is commendably honest regarding the implications of methodological naturalism. Eschewing Stephen Jay Gould's irenic principle that science and religion have "non-overlapping magisteria" and that science neither affirms nor denies the existence of supernatural beings, Schafersman argues that methodological naturalism logically entails ontological naturalism. Naturalism is the most reasonable ontology, because its reliability has been demonstrated over and over again: it has been examined, tested, and repeatedly corroborated by empirical, rational and skeptical methods. Decoupling ontological naturalism from methodological naturalism is obtuse and morally perverse: it is something that only a robot would do. Doing science the right way means that you have to be an atheist.

There are several things wrong with Professor Schafersman's argument. Specifically:

(a) In the 1997 version of his essay, Schafersman describes naturalism as an unfalsifiable meta-hypothesis, which has a special status, above that of ordinary scientific hypotheses. If he is right, then one of the classic objections (see below) to allowing supernaturalism in science - namely, that it is untestable, as one cannot perform tests on a supernatural Being - collapses, for on his own account, naturalism is also unfalsifiable.

(b) Belief in the supernatural does not entail belief in miracles.

(c) The creation of the cosmos would not be a miracle in the strict sense, as it would not violate existing laws of Nature.

(d) Charles Babbage refuted Hume's argument 180 years ago in his Ninth Bridgewater Treatise, when he argued that the independent testimony of a sufficient number of witnesses would suffice to establish the reality of a miracle.

11. Scientists can't perform tests on supernatural beings

A eleventh objection to "God-talk" in science is that scientists conduct their research by performing tests that support or falsify hypotheses, and one cannot perform tests on a supernatural Being. Or as Zack Kopplin's 74 Nobel Laureates wrote in their letter, 74 Nobel Laureates Call for a Repeal of the LSEA (originally posted on April 19, 2011): "Science offers testable, and therefore falsifiable, explanations for natural phenomena... Science is not equipped to evaluate supernatural explanations for our observations... An explanatory principle that by its nature cannot be tested is outside the realm of science."

Robert Pennock makes the same argument in his 2011 essay, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), 177-206. DOI: 10.1007/s11229-009-9547-3), where he writes:

MN [Methodological naturalism] is not dogma; it continues to be accepted in part because of its success - it works. Moreover, we do not necessarily rule out modifying the ground rule if someone were to find a workable method of finding evidence for supernatural hypotheses. On my analysis of the relevant concepts I find it hard to even imagine what such an alternative method would look like and I have seen no proposal that comes close to being conceptually coherent (certainly IDCs [intelligent design creationists] do not have such a method) but I remain open to being show wrong." (p. 199)

One oft-heard (but unsatisfactory) reply is that the "testability objection" proves too much: for if granted, it would allow only the experimental sciences to qualify as bona fide sciences, leaving historical sciences such as archaeology out in the cold. However, this is a poor argument: archaeologists can, for instance, study various techniques proposed for making stone tools (e.g. Acheulean hand-axes), in order to ascertain which ones would have worked best and are most likely to have been used by prehistoric man. They can then make falsifiable predictions about the flaking patterns that should be found on the tools, based on their hypotheses.

A better reply is that while it is true that one cannot perform tests that support or falsify scientific hypotheses on a Deity, we are also unable to perform tests on any intelligent agent whose intellect is vastly more advanced than our own. Or as Arthur C. Clarke put it in his Third Law: "Any sufficiently advanced technology is indistinguishable from magic." The above objection, if successful, would rule out not only supernaturalism, but also the hypothesis that life on Earth was deliberately created by aliens four billion years ago, in an act of intelligently directed panspermia. A counter-reply might be made that in principle, one could perform tests on these aliens, if they were still alive and willing to co-operate. But one could make similar requests of a co-operative Deity: "Could we just see you create a cell, please, in slow motion?" And while there is no reason in principle why either the alien or the Deity could not comply, it would be very silly to expect either to do so.

But the best reply to this objection is that it fails to distinguish between the being and the agency of a supernatural Deity. One cannot perform tests upon a supernatural Being as such; but one can certainly perform tests that support or falsify hypotheses relating to the Deity's mode of agency in the world - the "when", "where", "how" and even "why". For instance, one can attempt to identify periods in the Earth's past (e.g. the Cambrian explosion) when the complexity of fossil organisms increased relatively suddenly, and then inquire whether this increase was merely apparent or real. If it was real, one can ask whether these sudden bursts of complexity could have been front-loaded into the universe by carefully rigging the initial conditions at the Big Bang (thereby preventing the need for subsequent "manipulation"), or whether these relatively rapid jumps in biological information must have been "injected" into the cosmos periodically, at some time after the Big Bang. One can then inquire where these increases in complexity occurred, by looking for life beyond our Earth, and by performing tests as to what kinds of organisms can survive inter-stellar trips (panspermia). One might also attempt to scientifically verify or falsify the multiverse hypothesis, in order to ascertain whether life could have originated outside our universe. Finally, one might perform laboratory tests with the aim of identifying the easiest ways of genetically engineering any rapid increases in biological complexity that occurred in the past. This might shed light on the "how" of Intelligent Design. To identify the "why", one might list some possible aims that the Designer could have had in establishing the cosmos (e.g. the production of stars, or of life, or of intelligent life), and then identify which of these aims are the most sensitive to tiny variations in the constants of Nature or the initial conditions of the Big Bang.

The philosopher Elliott Sober also argues that some some claims about supernatural beings are testable. Sober providesd the following example:

the claim that an omnipotent supernatural being wanted above all that everything in nature be purple.

This claim is obviously testable: we can see that since some things are green, the claim must be false.

In response, Robert Pennock has argued that Sober's claim is not testable, after all:

Might not all of nature now indeed “be purple” in its noumenal substance, irrespective of its accidents, as wine purportedly becomes blood without observable change in the miracle of the Eucharist? (p. 552)

Bradley Monton has a ready reply to Pennock. He suggests that Sober's claim can easily be amended as follows:

the claim that an omnipotent supernatural being wanted above all that everything in nature APPEARS TO US TO BE purple.

That's a claim that can easily be tested - and falsified.

12. A supernatural being, if it existed, would be incomprehensible and hence outside the ken of science

The twelfth and perhaps the most powerful reason for excluding the supernatural from the domain of science is that if a supernatural Being exists, it must be utterly incomprehensible to us. Science, however, deals with what is comprehensible; hence there can never be any place for the supernatural in science. Robert Pennock urges this point forcefully in his 2011 essay, "Can't philosophers tell the difference between science and religion?: Demarcation revisited" (Synthese 178(2), 177-206. DOI: 10.1007/s11229-009-9547-3) when he writes:

"Would it even be intelligible to speak of supernatural "weight" or supernatural "color"? If these were truly meant to be different from the notions of weight and color as we understand these concepts in terms of our ordinary natural experience, then we have no ground upon which to draw any inference about them. Supernatural "design" is of a kind. As Hume pointed out, we have no experience and thus no knowledge of divine attributes. Those who think otherwise, whether in the service of proving or disproving the divine, invariably do so by illegitimately assuming naturalized notions of the key terms or other naturalized background assumptions." (p. 189)

Before I explain where this argument goes wrong, I'd like to discuss what it gets right. What the argument does establish is that there can be no science of the supernatural as such, since we have no direct acquaintance with it. God cannot be an object of scientific study. This follows from principle (b) above: science is the study of physical phenomena which are found in Nature. The existence of God, I would argue, may be inferred - contrary to the claims of methodological naturalism - but scientists cannot examine God Himself.

But this is a point readily acknowledged by Intelligent Design proponents. For instance, in a recent post entitled Why science can't study the supernatural – A physicist's view on the ID Web site Uncommon Descent, physicist Rob Sheldon writes:

...[T]he Enlightenment advanced precisely where it ignored the paranormal. Thus it would seem that studying the paranormal wasn't merely a distraction, but a degradation of science.

Stanley Jaki argues in "The Savior of Science" and several of his other books, that bad metaphysics, such as looking for paranormal effects, waylaid the nascent scientific progress of the Greeks, the Babylonians, the Persians, the Caliphate and even the Jewish Kabbala. Only the severe discipline of the Enlightenment materialism could negotiate the shoals of bad metaphysics.

I've come to a similar answer, though phrased a little differently. Inasmuch as the paranormal and spiritism are "personal", possessing the characteristics of contingent personality, then it is dangerous to study them as a machine. This is like BF Skinner studying humans as if they were a computer program.

Economists can tell you the danger of doing this. Not only does this give the wrong answer, but it even gives the wrong questions. What makes people people, and what makes the divine divine is precisely the personal, and therefore science does a disservice to theology when it reduces the personal to machinery. But worse, it invites the ghost into the machine.

The problem with Pennock's argument is not its assertion that God cannot be the object of scientific study, but its more sweeping claim that all discourse about God is scientifically meaningless, because "we have no experience and thus no knowledge of divine attributes." This argument founders on the same point that I raised earlier when distinguishing between the being and the agency of a supernatural Deity: all it proves is that scientists can never understand the nature of God. However, it fails to establish that we can never understand that why, what, when, where and how of His agency. In my reply to the previous objection above, I suggested some possible avenues for scientifically investigating this problem. The fact that scientists have not yet succeeded in answering these questions is no reason for them to refrain from even trying.

13. The inference to a supernatural being is illicit because its motives are unknowable to us

The thirteenth reason for excluding the supernatural from the domain of science is that any scientific inference to a supernatural being is illicit on methodological grounds, because its motives are unknowable to us.

Reply:

1. The design inferences don't require a knowledge of motive. Look at Arthur C. Clarke's monolith. Form is enough. Specify the conditions: high probabilistic complexity; high but not too high Kolmogorov complexity (in terms of the number of steps required to make it); low descriptive complexity. See http://www.uncommondescent.com/intelligent-design/of-little-green-men-and-csi-lite/

2. The argument confuses external with internal finality. Knowledge of the latter is enough, for a living thing.

3. In any case, It is possible for scientists to deduce the functionality of an object, simply by inspecting it. As Richard Dawkins puts it:

[A]ny engineer can recognize an object that has been designed, even poorly designed, for a purpose, and he can usually work out what that purpose is just by looking at the structure of the object (The Blind Watchmaker, 1986, p. 21, italics mine).

14. A supernatural being cannot explain bad design

The fourteenth reason for excluding the supernatural from the domain of science is that if a supernatural Being fails to explain instances of bad design we find in the world.

Reply: This criticism commits the Pegasus fallacy: if something is imaginable it's possible. Any criticism of a design should be disallowed unless the objector can explain in detail how the structure could have been made better, using natural processes.

15. Supernaturalism cannot explain the evil in the cosmos

The fifteenth reason for excluding the supernatural from the domain of science is that the hypothesis of a supernatural Being fails to explain the existence of natural evil in the cosmos. Michael Ruse articulates this objection with great passion in his article, Intelligent design is an oxymoron (The Guardian, Wednesday, 5 May 2010):

As soon as you bring God into the world on a daily creative basis, then the theodicy problem – the problem of evil – rears its ugly head. If God works away miraculously to do the very complex, presumably in the name of goodness, then why on earth does God not occasionally get involved miraculously to prevent the very simple with horrendous consequences? Some very, very minor genetic changes have truly dreadful effects, causing people life-long pain and despair. If God thought it worth His time to make the blood clot, then why was it not worth His time to prevent Huntingdon's (sic) Chorea?

The objection certainly carries weight.

1. The question of why God doesn't work miracles is not a scientific one. Science can only speak of God in relation to the world as it is today, and ask whether the laws governing any natural process could be tweaked in order to make the world a more hospitable place. As far as we can tell, the answer appears to be in the negative.

2. Evil is not pervasive. If we examine the laws of physics and chemistry, we find no evil there. On the contrary, we find great beauty and mathematical elegance, which points to their having been created by a Mind.

3. The laws of physics are at least locally optimal: there is no way to improve them so as to make them more "life-friendly."

4. The fundamental features of all living organisms - e.g. the DNA molecule - are also ideally designed.

5. To create a real problem for supernaturalism, a natural evil would have to be preventable by a better design which did not require any laws of nature to be broken.

6. Finally, supernaturalism does not imply a commitment to miracles. A miracle only occurs if a law of Nature is violated. If God was capable of producing life on Earth without resorting to miracles, then why should we expect Him to miraculously prevent disease?

I conclude, then, that there are no convincing grounds that have been put forward to date for excluding the supernatural from the domain of science.

Does Intelligent Design violate the principles of methodological naturalism, and if so, in what version?

Proponents of the cosmological version of Intelligent Design argue for the existence of a Cosmic Designer, citing (among other things) the fact that stars, planets and deep-space structures such as the Carina Nebula would not form in a universe with significantly different physical constants. Although a Designer of the cosmos would presumably be a supernatural Being, proponents of cosmological Intelligent Design are treated with a measure of respect in the scientific community, while proponents of biological Intelligent Design, who argue that organisms were originally designed by an Intelligent Being who may or may not have been supernatural, are generally ostracized by their fellow scientists. Image courtesy of NASA, ESA, hubblesite.org and Wikipedia.

Intelligent Design theory is regarded by most scientists as highly suspect, because although it does not positively declare the Designer of life and the universe to have been a supernatural Deity, it certainly leaves the door open to that possibility. This suspicion is reinforced by the fact that Intelligent Design proponents have attempted to find an explanation for not only the observable universe, but also the multiverse itself. For instance, Robin Collins' cosmological fine-tuning argument, The Teleological Argument: An Exploration of the Fine-Tuning of the Universe (in The Blackwell Companion to Natural Theology, edited by William Lane Craig and J. P. Moreland, 2009, Blackwell Publishing Ltd. ISBN: 978-1-405-17657-6), which attempts to demonstrate on both scientific and mathematical grounds that any multiverse beyond our universe must also have been designed, seems to point to an Intelligence transcending any kind of space and time – and physics. That certainly sounds supernatural to many people.

In reply: if Intelligent Design theory is deemed suspect because of its refusal to rule out a supernatural cause of the universe, then the whole science of cosmology is in serious trouble. Recent scientific findings indicate that not only did the observable universe have a beginning, but also, any multiverse containing our universe must have had a beginning as well. The idea that the multiverse simply popped into existence without a cause explains nothing, and for that reason strikes most people as absurd. So we are left with the notion that the multiverse had a supernatural Cause. Must we then declare cosmology to be unscientific? (See my recent post, Vilenkin's verdict: "All the evidence we have says that the universe had a beginning", in which I discussed the findings of cosmologist Alexander Vilenkin of Tufts University in Boston, who now declares that the multiverse could not have had an eternal past, contrary to what scientists had previously thought.)

Before I continue, I would like to distinguish between two versions of Intelligent Design: cosmological Intelligent Design (which is concerned with evidence that the cosmos as a whole was intelligently designed) and biological Intelligent Design (which confines itself to the question of whether life on Earth was designed). One can subscribe to either of these versions of Intelligent Design, or to both (as I do).

The point I wish to make here is that by itself, biological Intelligent Design is perfectly compatible with methodological naturalism. For instance, you could say that aliens from another planet designed life on Earth, if you wanted. Or you could even say that aliens in another universe created this universe as a kind of simulation, and fine-tuned its parameters and initial conditions so that it would eventually give rise to intelligent life. So the charge of supernaturalism made against the Intelligent Design movement by the 75 Nobel Prize winners who endorsed Zack Kopplin's petition against the Louisiana Science Education Act is simply wrong, period. Rejecting Darwinian evolution in favor of biological Intelligent Design does not commit you to supernaturalism, per se.

There is thus a glaring inconsistency in the fact that scientists with religious beliefs (such as Francis Collins) can keep their scientific reputations intact after publicly announcing that they accept the cosmological fine-tuning argument, while scientists who declare their belief that life on Earth was intelligently designed, are likely to find that their reputation is forever ruined. After all, which version of Intelligent Design contravenes methodological naturalism? Not biological Intelligent Design, but cosmological Intelligent Design! I therefore find it deeply puzzling that scientists who believe in cosmological fine-tuning but make a point of publicly rejecting biological Intelligent Design continue to be held in high esteem by the scientific community, while biological Intelligent Design proponents are regarded as pariahs, even when they declare themselves agnostic about the origin of the cosmos and make no attempt to challenge the principle of methodological naturalism.

So, where does all this leave us? Is Intelligent Design theory neutral or hostile with regard to methodological naturalism?

In my discussion above of what methodological naturalism is, I defined methodological naturalism in the proper sense of the term, as the following principle:

(g) When doing science, we should assume that natural causes are sufficient to account for all observed phenomena, and that for precisely this reason, all talk of the supernatural is banished from science.

If we define methodological naturalism in this way, then it has to be acknowledged that Intelligent Design theory in general is at odds with methodological naturalism, simply by refusing to rule out a supernatural Designer of Nature, and by refusing to affirm that natural causes are sufficient to account for all observed phenomena. But by the same token, it could be argued that the entire discipline of cosmology is vulnerable to the same criticism.

What I shall attempt to demonstrate in Parts Five and Six

What I shall attempt to do in Parts Five and Six of my reply to Zack Kopplin is to step back in time and look at how famous scientists of the past viewed the boundary between science and religion – and in particular, how these scientists viewed the legitimacy of Intelligent Design arguments. If I can demonstrate that these scientists frequently made use of Intelligent Design arguments, and argued for the existence of the supernatural in their scientific writings, then the commonly heard claim, that methodological naturalism is and always has been a vital part of the way scientists do science, will be exposed as utter bunk.

What I'll be arguing in Part Six is that these scientists had a different bright line: they did not believe that scientific questions should be settled by an appeal to revelation (e.g. the Bible), but by observation and experimentation. Nevertheless, that did not stop them from arguing that various features of the empirical world attest to the existence of a wise and benevolent supernatural Creator. The modern Intelligent Design movement is much more circumspect in its claims, since it endeavors to be as rigorous as possible in its scientific reasoning. Even if we can establish that the complex systems found in living things were intelligently designed, it does not necessarily follow that this Designer was or is a supernatural Being, let alone an infinite, omniscient, omnibenevolent Being. One would need to argue on non-scientific grounds for those conclusions, because at the present time there are no scientific arguments that will take us that far – only metaphysical ones. That may change in the future, of course.

I believe that methodological naturalism is a science-stopper. The founding members of The Royal Society (which was founded in 1660) evidently thought so too. As we'll see, some of its founding members (Robert Boyle, Bishop John Wilkins, and the first Curator of Experiments, Robert Hooke) were Intelligent Design proponents, as was Sir Isaac Newton, the Society's 12th President! What's more, the Royal Society's motto, "Nullius in Verba" ("Take nobody's word for it") proclaims that facts in science are established on the basis of experiments, rather than appeals to authority – which implies, among other things, that no human authority has the right to tell scientists that the existence of God is off-limits as a subject for legitimate scientific enquiry. "Take nobody's word for it" entails that we cannot dogmatically confine the domain of science to the natural world. Who knows? Maybe one day there will be a "science of the supernatural."

B. Hume, Kant and the philosophical roots of Methodological Naturalism

David Hume - the grand-father of Methodological Naturalism

An 18th century portrait of the Scottish philosopher David Hume (1711-1776), by Allan Ramsay. Scottish National Portrait Gallery. Image courtesy of Wikipedia.

The empiricism of David Hume (1711-1776)

David Hume's sceptical writings had a profound influence on Kant's thinking. In the Preface to his Prolegomena to Any Future Metaphysics (1783), Kant wrote (4, 260; 10): "I freely admit that it was the remembrance of David Hume which, many years ago, first interrupted my dogmatic slumber and gave my investigations in the field of speculative philosophy a completely different direction."

In his classic work, An Enquiry Concerning Human Understanding (1748), Hume was concerned with establishing the limits of human knowledge and of scientific enquiry.

(a) What does it mean to have a concept?

[W]e may divide all the perceptions of the mind into two classes or species, which are distinguished by their different degrees of force and vivacity. By the term impression ... I mean all our more lively perceptions, when we hear, or see, or feel, or love, or hate, or desire, or will. And impressions are distinguished from ideas, which are the less lively perceptions, of which we are conscious, when we reflect on any of those sensations or movements above mentioned. (Section II - Of the Origin of Ideas.)

...[The] creative power of the mind amounts to no more than the faculty of compounding, transposing, augmenting, or diminishing the materials afforded us by the senses and experience. When we think of a golden mountain, we only join two consistent ideas, gold, and mountain, with which we were formerly acquainted. A virtuous horse we can conceive; because, from our own feeling, we can conceive virtue; and this we may unite to the figure and shape of a horse, which is an animal familiar to us. In short, all our ideas or more feeble perceptions are copies of our impressions or more lively ones.

To me, there appear to be only three principles of connexion among ideas, namely, Resemblance, Contiguity in time or place, and Cause or Effect. (Section III - Of the Association of Ideas.)

All reasonings concerning matter of fact seem to be founded on the relation of Cause and Effect. By means of that relation alone we can go beyond the evidence of our memory and senses. (Section IV - Sceptical Doubts Concerning the Operations of the Understanding. Part I.)

(b) What is a cause?

Hume argued that our knowledge of causes is based entirely on experience. But he went further, and argued that the very idea of a cause was derived from nothing more than sensory impressions of the outside world. Because cause and effect are distinct, each may be conceived of as occurring in the absence of the other; hence we can never infer an effect from a cause on the basis of reason alone. Hume insists that for all we know, any effect might follow from any cause. Only experience can tell us which effects follow from which causes. Sometimes we find that an object of a certain kind is always conjoined to, or attended by, an object of another kind. Then we can define the first as the cause of the second. For Hume, then, constant conjunction is the defining feature of a cause: "we may define a cause to be an object, followed by another, and where all the objects similar to the first are followed by objects similar to the second." We can then say that if the cause had not occurred, the effect would not have occurred.

The naturalistic implications of Hume's analysis of causation should be immediately apparent. For if causation is nothing more than a relation between the objects that we know through our sensory impressions, then the notion of a Cause of the cosmos no longer makes sense, since such a Cause would lie beyond the reach of the senses. We never see God making anything, and we could certainly never have observed Him making the world.

The following quotes convey the tenor of Hume's thought:

Were any object presented to us, and were we required to pronounce concerning the effect, which will result from it, without consulting past observation; after what manner, I beseech you, must the mind proceed in this operation? It must invent or imagine some event, which it ascribes to the object as its effect; and it is plain that this invention must be entirely arbitrary. The mind can never possibly find the effect in the supposed cause, by the most accurate scrutiny and examination. For the effect is totally different from the cause, and consequently can never be discovered in it. Motion in the second Billiard-ball is a quite distinct event from motion in the first; nor is there anything in the one to suggest the smallest hint of the other. (Section IV - Sceptical Doubts Concerning the Operations of the Understanding. Part I.)

In a word, then, every effect is a distinct event from its cause. It could not, therefore, be discovered in the cause, and the first invention or conception of it, a priori, must be entirely arbitrary. And even after it is suggested, the conjunction of it with the cause must appear equally arbitrary; since there are always many other effects, which, to reason, must seem fully as consistent and natural. In vain, therefore, should we pretend to determine any single event, or infer any cause or effect, without the assistance of observation and experience. ()

I have found that such an object has always been attended with such an effect, and I foresee, that other objects, which are, in appearance, similar, will be attended with similar effects. I shall allow, if you please, that the one proposition may justly be inferred from the other: I know, in fact, that it always is inferred. But if you insist that the inference is made by a chain of reasoning, I desire you to produce that reasoning. The connexion between these propositions is not intuitive. (Section IV - Sceptical Doubts Concerning the Operations of the Understanding. Part II.)

Suppose a person, though endowed with the strongest faculties of reason and reflection, to be brought on a sudden into this world; he would, indeed, immediately observe a continual succession of objects, and one event following another; but he would not be able to discover anything farther. He would not, at first, by any reasoning, be able to reach the idea of cause and effect; since the particular powers, by which all natural operations are performed, never appear to the senses; nor is it reasonable to conclude, merely because one event, in one instance, precedes another, that therefore the one is the cause, the other the effect. Their conjunction may be arbitrary and casual. There may be no reason to infer the existence of one from the appearance of the other. (Section V - Sceptical Solution of these Doubts. Part I.)

All belief of matter of fact or real existence is derived merely from some object, present to the memory or senses, and a customary conjunction between that and some other object. Or in other words; having found, in many instances, that any two kinds of objects--flame and heat, snow and cold--have always been conjoined together; if flame or snow be presented anew to the senses, the mind is carried by custom to expect heat or cold, and to believe that such a quality does exist, and will discover itself upon a nearer approach.

Similar objects are always conjoined with similar. Of this we have experience. Suitably to this experience, therefore, we may define a cause to be an object, followed by another, and where all the objects similar to the first are followed by objects similar to the second. Or in other words where, if the first object had not been, the second never had existed. The appearance of a cause always conveys the mind, by a customary transition, to the idea of the effect. Of this also we have experience. We may, therefore, suitably to this experience, form another definition of cause, and call it, an object followed by another, and whose appearance always conveys the thought to that other. (Section VII - Of the Idea of Necessary Connexion. Part II.)

We find by experience, that a body at rest or in motion continues for ever in its present state, till put from it by some new cause; and that a body impelled takes as much motion from the impelling body as it acquires itself. These are facts. When we call this a vis inertiae, we only mark these facts, without pretending to have any idea of the inert power; in the same manner as, when we talk of gravity, we mean certain effects, without comprehending that active power.

That impious maxim of the ancient philosophy, Ex nihilo, nihil fit, by which the creation of matter was excluded, ceases to be a maxim, according to this philosophy. Not only the will of the supreme Being may create matter; but, for aught, we know a priori, the will of any other being might create it, or any other cause, that the most whimsical imagination can assign. (Section XII - Of the Academical or Sceptical Philosophy. Part III.)

A Critique of Hume's naturalistic view of causation.

Hume's analysis of causation has been critiqued extensively, and I shall not attempt to summarize those critiques here (for an overview see here, here, and here). Instead I shall focus on just two major criticisms, which pertain to the very nature of science itself. The first of these is that Hume's analysis of causality, if correct, would undercut the very foundations of science itself, by rendering inductive inference illegitimate. If, as Hume asserts, causes do not guarantee their effects, then we cannot be sure that they will bring about those effects in the future. Put simply: if Hume is right, then it seems we have no good grounds for believing that the Sun will rise tomorrow. All we have is a psychological habit of belief: we can't help expecting that the Sun will rise tomorrow, whether or not it will. But a habit of the mind can tell us nothing about objective reality. Even statistical inferences, such as the expectation that a fair coin will land on "heads" 50% of the time, would be rendered suspect by Hume's account of causality. As the Internet Encyclopedia of Philosophy puts it in its article, David Hume: Causation:

Once we realize that "A must bring about B" is tantamount merely to "Due to their constant conjunction, we are psychologically certain that B will follow A", then we are left with a very weak notion of necessity. This tenuous grasp on causal efficacy helps give rise to the Problem of Induction – that we are not reasonably justified in making any inductive inference about the world.

And yet there are many sciences which make practical recommendations about how we should act, based on the notion that causes do reliably bring about their effects. The Surgeon-General warns us that smoking causes lung cancer, and we are constantly warned of the need to curb our CO2 emissions, because they cause global warming. Hume's skeptical account would rob these warnings of their epistemic warrant. On his account, one could legitimately ask: "How do you know?"

I should point out that some Hume scholars interpret Hume in a more conservative fashion.

(b) Laws of Nature

There are some causes, which are entirely uniform and constant in producing a particular effect; and no instance has ever yet been found of any failure or irregularity in their operation. Fire has always burned, and water suffocated every human creature: the production of motion by impulse and gravity is an universal law, which has hitherto admitted of no exception. (Section VI - Of Probability. Part I.)

It is universally allowed that matter, in all its operations, is actuated by a necessary force, and that every natural effect is so precisely determined by the energy of its cause that no other effect, in such particular circumstances, could possibly have resulted from it. (Section VIII - Of Liberty and Necessity. Part I.)

The philosopher, if he be consistent, must apply the same reasoning to the actions and volitions of intelligent agents. The most irregular and unexpected resolutions of men may frequently be accounted for by those who know every particular circumstance of their character and situation.

A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined. (Section X - Of Miracles. Part I.)

When anyone tells me, that he saw a dead man restored to life, I immediately consider with myself, whether it be more probable, that this person should either deceive or be deceived, or that the fact, which he relates, should really have happened. I weigh the one miracle against the other; and according to the superiority, which I discover, I pronounce my decision, and always reject the greater miracle. If the falsehood of his testimony would be more miraculous, than the event which he relates; then, and not till then, can he pretend to command my belief or opinion.

(c) The limits of scientific explanation

Hence we may discover the reason why no philosopher, who is rational and modest, has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power, which produces any single effect in the universe. It is confessed, that the utmost effort of human reason is to reduce the principles, productive of natural phenomena, to a greater simplicity, and to resolve the many particular effects into a few general causes, by means of reasonings from analogy, experience, and observation. But as to the causes of these general causes, we should in vain attempt their discovery; nor shall we ever be able to satisfy ourselves, by any particular explication of them. These ultimate springs and principles are totally shut up from human curiosity and enquiry. Elasticity, gravity, cohesion of parts, communication of motion by impulse; these are probably the ultimate causes and principles which we shall ever discover in nature; and we may esteem ourselves sufficiently happy, if, by accurate enquiry and reasoning, we can trace up the particular phenomena to, or near to, these general principles. The most perfect philosophy of the natural kind only staves off our ignorance a little longer: as perhaps the most perfect philosophy of the moral or metaphysical kind serves only to discover larger portions of it. Thus the observation of human blindness and weakness is the result of all philosophy, and meets us at every turn, in spite of our endeavours to elude or avoid it. (Section IV - Sceptical Doubts Concerning the Operations of the Understanding. Part I.)

The only immediate utility of all sciences, is to teach us, how to control and regulate future events by their causes. (Section VII - Of the Idea of Necessary Connexion. Part II.)

How could politics be a science, if laws and forms of government had not a uniform influence upon society? ... It seems almost impossible, therefore, to engage either in science or action of any kind without acknowledging the doctrine of necessity, and this inference from motive to voluntary actions, from characters to conduct. (Section VIII - Of Liberty and Necessity. Part I.)

(d) What scientists can and cannot know: The proper objects of scientific enquiry

All knowledge, said Hume, is based on logical reasoning or experience. Absolutely certain knowledge, or demonstration, can only come from logical reasoning. However, logical reasoning can only yield knowledge of mathematical abstractions, and not of reality. Experience is needed to give us knowledge of what is real. This knowledge, however, is not demonstrative but a posteriori. Additionally, Hume insisted that it is only through experience that we can know the cause of any given effect. Towards the end of his book, Hume undertakes to make an "examination into the natural powers of the human mind and to compare them with their objects", in order to "find what are the proper subjects of science and enquiry". He concludes:

It seems to me, that the only objects of the abstract science or of demonstration are quantity and number, and that all attempts to extend this more perfect species of knowledge beyond these bounds are mere sophistry and illusion... [Q]uantity and number... may safely, I think, be pronounced the only proper objects of knowledge and demonstration...

All other enquiries of men regard only matter of fact and existence; and these are evidently incapable of demonstration. Whatever is may not be. No negation of a fact can involve a contradiction. The non-existence of any being, without exception, is as clear and distinct an idea as its existence...

The existence ... of any being can only be proved by arguments from its cause or its effect; and these arguments are founded entirely on experience. If we reason a priori, anything may appear able to produce anything. The falling of a pebble may, for aught we know, extinguish the sun; or the wish of a man control the planets in their orbits. It is only experience, which teaches us the nature and bounds of cause and effect, and enables us to infer the existence of one object from that of another...

The sciences, which treat of general facts, are politics, natural philosophy, physic, chemistry, &c. where the qualities, causes and effects of a whole species of objects are enquired into...

When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion. (Section XII, Part III.)

(e) Hume's rejection of the Design Argument

From the above remarks, it is not difficult to see why Hume had little time for the Design Argument for the existence of God. In his Dialogues Concerning Natural Religion, Hume insisted that no matter how complex and contrived a structure in the natural world (such as the human eye) might appear to us, we could have no knowledge of its cause merely from examining the object itself. Thus if the eye was intelligently designed, we could only know this from having seen an Intelligent Being design it. Since no-one has seen God design anything in Nature, it is impossible for us to infer His existence from His created works.

Although Hume did not explicitly articulate the principle of methodological naturalism in his writings, it is clearly implied by his epistemological principles. The task of natural science, according to Hume, is to enquire into "the qualities, causes and effects of a whole species of objects", using arguments that are "founded entirely on experience". Since God is not an object of experience, it follows that on Hume's view, there could be no place for God in science. By the same token, there could be no place for any other immaterial supernatural Being, either.

How can any thing, that exists from eternity, have a cause; since that relation implies a priority in time and a beginning of existence? (Dialogue 9.8)

Whatever we conceive as existent, we can also conceive as non-existent. There is no being, therefore, whose non-existence implies a contradiction. (Dialogue 9.5)

But farther; why may not the material universe be the necessarily-existent Being, according to this pretended explication of necessity? We dare not affirm that we know all the qualities of matter; and for aught we can determine, it may contain some qualities, which, were they known, would make its non-existence appear as great a contradiction as that twice two is five. (Dialogue 9.7)

Look round the world: contemplate the whole and every part of it: You will find it to be nothing but one great machine, subdivided into an infinite number of lesser machines, which again admit of subdivisions, to a degree beyond what human senses and faculties can trace and explain. All these various machines, and even their most minute parts, are adjusted to each other with an accuracy, which ravishes into admiration all men, who have ever contemplated them. The curious adapting of means to ends, throughout all nature, resembles exactly, though it much exceeds, the productions of human contrivance; of human design, thought, wisdom, and intelligence. Since therefore the effects resemble each other, we are led to infer, by all the rules of analogy, that the causes also resemble; and that the Author of Nature is somewhat similar to the mind of man... (Dialogue 2.5)

...[O]rder, arrangement, or the adjustment of final causes is not, of itself, any proof of design; but only so far as it has been experienced to proceed from that principle. (Dialogue 2.14)

[T]he subject in which you are engaged exceeds all human reason and enquiry. Can you pretend to show any ... similarity between the fabric of a house, and the generation of a universe? Have you ever seen Nature in any such situation as resembles the first arrangement of the elements? Have worlds ever been formed under your eye? (Dialogue 2.28)

To ascertain this reasoning, it were requisite, that we had experience of the origin of worlds; and it is not sufficient surely, that we have seen ships and cities arise from human art and contrivance. (Dialogue 2.25)

If the material world rests upon a similar ideal world, this ideal world must rest upon some other; and so on, without end. It were better, therefore, never to look beyond the present material world. By supposing it to contain the principle of its order within itself, we really assert it to be God; and the sooner we arrive at that divine Being so much the better. (Dialogue 4.9)

Why not stop at the material world? How can we satisfy ourselves without going on in infinitum? And after all, what satisfaction is there in that infinite progression? (Dialogue 4.9)

For aught we can know a priori, matter may contain the source or spring of order originally, within itself, as well as mind does; and there is no more difficulty in conceiving, that the several elements, from an internal unknown cause, may fall into the most exquisite arrangement, than to conceive that their ideas, in the great, universal mind, from a like internal, unknown cause, fall into that arrangement. (Dialogue 2.14)

... I would fain know, why it is not as good sense to say, that the parts of the material world fall into order, of themselves, and by their own nature. (Dialogue 4.10)

Now if we survey the universe, so far as it falls under our knowledge, it bears a great resemblance to an animal or organized body, and seems actuated with a like principle of life and motion. A continual circulation of matter in it produces no disorder: a continual waste in every part is incessantly repaired: the closest sympathy is perceived throughout the entire system: and each part or member, in performing its proper offices, operates both to its own preservation and to that of the whole. The world, therefore, I infer, is an animal, and the Deity is the SOUL of the world, actuating it, and actuated by it. (Dialogue 6.3)

The world plainly resembles more an animal or a vegetable, than it does a watch or a knitting-loom. Its cause, therefore, it is more probable, resembles the cause of the former. The cause of the former is generation or vegetation. The cause, therefore, of the world, we may infer to be something similar or analogous to generation or vegetation. (Dialogue 7.3)

And when Cleanthes asks me what is the cause of my great vegetative or generative faculty, I am equally intitled to ask him the cause of his great reasoning principle. (Dialogue 7.14)

Nothing more repugnant to all their [the ancients'] notions, because nothing more repugnant to common experience, than mind without body; a mere spiritual substance, which fell not under their senses nor comprehension, and of which they had not observed one single instance throughout all nature. (Dialogue 6.5)

A great number of men join in building a house or ship, in rearing a city, in framing a commonwealth: why may not several deities combine in contriving and framing a world? (Dialogue 5.8)

While we are uncertain, whether there is one deity or many; whether the deity or deities, to whom we owe our existence, be perfect or imperfect, subordinate or supreme, dead or alive; what trust or confidence can we repose in them? What devotion or worship address to them? (Dialogue 6.1)

For as the cause ought only to be proportioned to the effect, and the effect, so far as it falls under our cognisance, is not infinite; what pretensions have we, upon your suppositions, to ascribe that attribute to the divine Being? (Dialogue 5.5)

For how can an effect, which either is finite, or, for aught we know, may be so; how can such an effect, I say, prove an infinite cause? (Dialogue 9.1)

Why is there any misery at all in the world? Not by chance surely. From some cause then. Is it from the intention of the Deity? But he is perfectly benevolent. Is it contrary to his intention? But he is almighty. (Dialogue 10.34)

In short, might not the Deity exterminate all ill, wherever it were to be found; and produce all good, without any preparation or long progress of causes and effects? (Dialogue 11.7)

There may four hypotheses be framed concerning the first causes of the universe; that they are endowed with perfect goodness, that they have perfect malice, that they are opposite and have both goodness and malice, that they have neither goodness nor malice. Mixt phenomena can never prove the two former unmixt principles. And the uniformity and steadiness of general laws seem to oppose the third. The fourth, therefore, seems by far the most probable. (Dialogue 11.15)

William Paley's response to Hume: Experience tells us that only intelligent agents make contrivances

A portrait of William Paley (1743-1805) by George Romney. 1802. National Portrait Gallery, London. Image courtesy of Wikipedia.

Hume died in 1776, and his posthumous Dialogues Concerning Natural Religion were published in 1779. Defenders of the Design Argument took careful note of David Hume's sceptical criticisms and reformulated their argument in order to rebut them. The most articulate defender of the Argument from Design in the early nineteenth century was William Paley. Paley's Natural Theology was published in 1802, twenty-three years after the publication of Hume's Dialogues Concerning Natural Religion. (The reason why I mention this fact is that many people still believe the oft-repeated myth that Hume refuted Paley's argument from design, which is absurdly anachronistic.) At the time when he wrote his Natural Theology, Paley had already read Hume's Dialogues; indeed, he even refers in passing to "Mr. Hume, in his posthumous dialogues" on page 512 of Chapter XXVI of his book. Moreover, a careful examination of Paley's design argument shows that he had anticipated and responded to Hume's main criticisms.

For the purposes of this post, I'd just like to draw attention to one major difference between the design argument put forward by the character Cleanthes (and subsequently refuted by the sceptical character Philo) in Hume's Dialogues Concerning Natural Religion, and the argument from design formulated by Paley. As Professor John Wright has pointed out in some online remarks on Hume's Dialogues, Cleanthes' design argument was an inductive argument based on an analogy between human artifacts (which we observe being produced by intelligent agents) and the "machines" (or "contrivances") that we find in Nature. Paley, on the other hand, argued that we could immediately infer Intelligent Design from any machine (natural or artificial) that we happen to find:

Paley thinks we infer the existence of an intelligent cause immediately from the observation of the machine itself. According to the argument which Cleanthes puts forward, the only reason we ascribe an intelligent cause to machines like watches, is because we discover from observation that they are created by beings with thought, wisdom and intelligence. (Paley had read Hume and was obviously aware of this difference in their arguments: see his answer to his first Objection.)

For Paley the inference from watch to intelligent watchmaker is no different from the inference from complex natural organisms to an intelligent designer. He is just trying to show you can make the same inference in both cases. For Cleanthes, on the other hand, it is important that we observe the maker in the case of the human productions and we do not in the case of the productions of nature. We observe the effects in both cases and that they are somewhat similar to each other. But we never observe the cause in the case of natural machines: it is only inferred through the scientific principle "like effects, like causes." Cleanthes draws the conclusion that the cause of natural machines something like a human mind, but very much greater.

Cleanthes' argument is a genuine inductive argument, based on observation of the relation of cause and effect in the case of human production; Paley's is not.

The reader may be wondering how Paley thought we could immediately infer that the eye had an Intelligent Designer, without having seen it being made. Paley's reply was that we could know this because the eye was what he termed a contrivance - that is, an object made up of multiple parts, all of which are adapted to a common purpose. Experience tells us that: (i) intelligent agency constantly produces contrivances; and (ii) intelligent agency is the only process known to produce contrivances:

Wherever we see marks of contrivance, we are led for its cause to an intelligent author. And this transition of the understanding is founded upon uniform experience. We see intelligence constantly contriving, that is, we see intelligence constantly producing effects, marked and distinguished by certain properties; not certain particular properties, but by a kind and class of properties, such as relation to an end, relation of parts to one another, and to a common purpose. We see, wherever we are witnesses to the actual formation of things, nothing except intelligence producing effects so marked and distinguished... In like manner, and upon the same foundation (which in truth is that of experience), we conclude that the works of nature proceed from intelligence and design, because, in the properties of relation to a purpose, subserviency to a use, they resemble what intelligence and design are constantly producing, and what nothing except intelligence and design ever produce at all.
(Natural Theology. 12th edition. J. Faulder: London, 1809, Chapter XXIII, pp. 413-415)

There are of course many other objections which Hume marshals against the design argument in his Dialogues Concerning Natural Religion. The principal objections relate to the imperfections found in living things; the possibility that Nature may be capable of creating order by itself through some process as yet unknown to us; and the impossibility of inferring whether there is one Designer or several, or whether the Designer is benevolent, malevolent or indifferent. Suffice it to say that Paley is familiar with these objections, and addresses them at considerable length in his book. Another popular objection, that living things reproduce and watches don't, is rebutted by Paley in Chapter II of his Natural Theology, in a devastatingly incisive fashion.

In the end, the fundamental disagreement between Hume and Paley is an epistemic one: it boils down to what justifies us in inferring the existence of an intelligent agent. Hume thinks that no structure, however complex it may be, can warrant a design inference on its own, and that we are only warranted in making such an inference if we know something about the goals, modus operandi and modus vivendi of the alleged designer(s); whereas Paley thinks that a system's having the property of being a contrivance is enough to warrant the inferential leap that it was designed.

Although Paley had read and responded to Hume, he had not read the work of Immanuel Kant, as it had not been translated into English when he died. It is to Kant's criticisms that we now turn.

Immanuel Kant - The True Father of Methodological Naturalism?

A painting of Immanuel Kant (1724-1804). Artist unknown. Image courtesy of Wikipedia.

http://www.iep.utm.edu/kantmeta/

http://plato.stanford.edu/entries/cosmological-argument/#3.5

http://www.iep.utm.edu/kant-rel/

http://www.britannica.com/EBchecked/topic/208087/first-cause

If there is any thinker who deserves to be called the father of methodological naturalism, it is the philosopher Immanuel Kant (1724-1804), who probed the foundations of human knowledge in his three works, Critique of Pure Reason (1781), Critique of Practical Reason (1788) and Critique of Judgement (1790). Despite his methodological naturalism, however, Kant had the highest regard for the teleological argument for the existence of God. What prevented him from incorporating this argument into natural science was his distrust of human reason. For Kant, the fact that human reason could only understand the world in teleological terms in no way proved the existence of an objective purpose in Nature, and still less did it prove the existence of a Creator who imbued Nature with a purpose. All it proved was that the human mind has its own built-in cognitive limitations. Because the human mind is unable to understand the workings of complex entities (such as living things) from the bottom up, and deduce their behavior from general laws, it tries to understand organisms teleologically instead, by asking what they are for. While this way of looking at living things is undeniably useful, it doesn't necessarily reflect the true nature of organisms, considered in themselves. Hence a teleological approach to Nature, taken by itself, could yield no knowledge of God.

Fundamental to Kant's philosophy was his division of reality, in his Critique of Pure Reason (1781), into two parts - the "phenomenal" or sensible aspect of things, which can be seen and touched and measured, and the "noumenal" aspect, involving the "thing in itself" rather than its observable categories. For Kant, the principal limitation of the human mind is that it is incapable of knowing things as they are in themselves; it can only know things as they appear to us. Kant relegated modern science to the realm of the phenomenal, and traditional morality and religion to the realm of the noumenal. He had a very special reason for doing this: the scientific laws developed by Isaac Newton in his Principia (1687) were thought to be totally deterministic, leaving no room for human freedom, and creating a tension between religion and science. Kant strove to reconcile the claims of modern science with those of traditional morality and religion by assigning them to separate spheres, and thereby preventing them from overlapping. On Kant's account, the determinism of modern science no longer threatened the freedom required by traditional morality, because science and therefore determinism applied only to appearances, and there was still room for freedom in the realm of things in themselves, where the self or soul was located. All natural events occur in time, and are thoroughly determined by causal chains that stretch backwards into the distant past. So there is no room for freedom in nature, which is deterministic in a strong sense. When I act freely, however, my noumenal self is an uncaused cause outside of time. Hence it is not subject to the deterministic laws of nature which our understanding uses to make sense of the world we experience.

Kant's philosophical reconciliation achieved peace between religion and science - but at a terrible cost. By assigning science to one realm of discourse and religion to another, Kant made it impossible for science to say anything about God or the supernatural. Methodological naturalism could truly be said to begin here.

Before I discuss Kant's methodological naturalism in detail, however, I'd like to step back and look at the writings of the philosopher David Hume (1711-1776), who may be considered a fore-runner to Kant, in many respects.

Some differences between Hume and Kant

In their article, Kant and Hume on Causality in the Stanford Encyclopedia of Philosophy, Graciela De Pierris and Michael Friedman draw attention to an important but little-known difference between Hume and Kant on scientific laws. For Hume, all scientific knowledge, including our knowledge of laws, was based entirely on experience:

To begin with, Hume does not consider Newton's "Axioms or Laws of Motion" as a priori in any sense (in Kant's terminology, neither analytic nor synthetic a priori). All of these laws, according to Hume, are simply "facts" inductively derived from (constant and regular) experience. Hume considers Newton's second law of motion (F = ma) in the Enquiry [concerning Human Understanding], section 4, part 1 (EHU 4.13; SBN 31): "Thus, it is a law of motion, discovered by experience, that the moment or force of any body in motion is in the compound ratio or proportion of its solid contents and its velocity .... Geometry assists us in the application of this law ... ; but still the discovery of the law itself is owing merely to experience, and all the abstract reasonings in the world could never lead us one step towards the knowledge of it."

Kant, on the other hand, famously held that the most fundamental scientific laws (namely, Newton's laws of motion) could be known a priori, independently of any experience:

...[I]n his Metaphysical Foundations of Natural Science, which ... appeared in 1786 (following the publication of the Prolegomena in 1783 and immediately preceding the publication of the second edition of the Critique in 1787) ... Kant articulates what he calls "pure natural science" in four chapters corresponding, respectively, to the four headings of the table of categories (quantity, quality, relation, and modality). In the third chapter or Mechanics (corresponding to the three categories of relation: substance, causality, and community) Kant derives three "laws of mechanics" corresponding, respectively, to the three Analogies of Experience: the permanence or conservation of the total quantity of matter, the law of inertia, and the equality of action and reaction—which Kant describes as a law of "the communication of motion" (4, 544; 84). All these laws, Kant makes clear, are synthetic a priori propositions, demonstrated a priori and "drawn from the essence of the thinking faculty itself" (4, 472; 8).

For Kant, therefore, the laws of the Newtonian science of nature are of two essentially different kinds. Kant regards Newton's three "Axioms or Laws of Motion" presented at the beginning of the Principia as synthetic a priori truths — which Kant himself attempts to demonstrate a priori in the Metaphysical Foundations. By contrast, Kant does not regard the inverse-square law of universal gravitation, which Newton establishes by a famous "deduction from the phenomena" in Book 3 of the Principia, as a synthetic a priori truth—and, accordingly, Kant does not attempt to demonstrate this law a priori in the Metaphysical Foundations. Nevertheless, Kant regards the synthetic a posteriori law of universal gravitation as "necessary and universally valid" in virtue of the way in which it is "determined" in relation to the "phenomena" by the synthetic a priori laws of pure natural science. And, since the latter, in turn, are “determined” from the a priori principles of the understanding, the a posteriori law of universal gravitation is thereby "determined" in relation to actual perceptions "in accordance with the general conditions of experience."

This invites an obvious question: if Kant held that human reason was capable of knowing the fundamental laws of Nature on an a priori basis, why was he so insistent that the human mind was incapable of knowing a priori that design in Nature requires a Designer?

Why Kant held that science could not take us to God

As we have seen, Kant held that in order to yield reliable knowledge of the world, science had to limit itself to the study of natural phenomena, since only these are accessible to our senses. Additionally, any a priori assumptions invoked by natural science had to be derived from the demands of pure speculative reason, as opposed to any practical human requirements. What this meant was that proper scientific explanations should be based on mechanical laws rather than teleology, as the former give us a pure understanding of how Nature works, while the latter reflect the limitations of our human attempts to grasp complex entities (such as organisms). Because we cannot deduce their behavior from mechanical principles alone, we try to understand them by asking what purpose their parts serve. For Kant, inferring the existence of God from the teleology we find in Nature was therefore bad science; all such a proof would show is that the human mind needs to assume God's existence in order to understand the world around us. That's different from showing that God actually exists. In order to obtain a solid assurance that such a God is real, we must look to proofs from practical reason, which concerns itself with morality. Kant argued that morality presupposes the existence of God. Having established His existence, we can then legitimately speak of the world as an expression of His Divine plan.

In Part II, chapter 68 of his 1790 work, The Critique of Judgement, Kant laid out his reasons for excluding both God and teleology from the domain of natural science:

Every science is in itself a system, and it is not enough in it to build in accordance with principles and thus to employ a technical procedure, but we must go to work with it architectonically, as a building subsisting for itself; we must not treat it as an additional wing or part of another building, but as a whole in itself, although we may subsequently make a passage from it into that other or conversely.

If then we introduce into the context of natural science the concept of God in order to explain the purposiveness in nature, and subsequently use this purposiveness to prove that there is a God, there is no internal consistency in either science [i.e. either in natural science or theology]; and a delusive circle brings them both into uncertainty, because they have allowed their boundaries to overlap.

The expression, a purpose of nature, already sufficiently prevents the confusion of mixing up natural science and the occasion that it gives for judging teleologically of its objects, with the consideration of God, and so of a theological derivation of them. We must not regard it as insignificant, if one interchanges this expression with that of a divine purpose in the ordering of nature, or gives out the latter as more suitable and proper for a pious soul, because it must come in the end to deriving these purposive forms in nature from a wise author of the world. On the contrary, we must carefully and modestly limit ourselves to the expression, a purpose of nature, which asserts exactly as much as we know....[N]atural science must judge of its objects, and, consequently, must seek in nature their causality according to the rule of purposes. So then it must not transgress its bounds in order to introduce into itself as a domestic principle that, to whose concept no experience can be commensurate, upon which we are only entitled to venture after the completion of natural science.

Natural characteristics which demonstrate themselves a priori, and consequently admit of insight into their possibility from universal principles without any admixture of experience, although they carry with them a technical purposiveness, yet cannot, because they are absolutely necessary, be referred to the Teleology of nature, as to a method belonging to Physics for solving its problems. Arithmetical or geometrical analogies, as well as universal mechanical laws, - however strange and admirable may seem to us the union of different rules, quite independent of one another according to all appearance, in a single principle, - possess on that account no claim to be teleological grounds of explanation in Physics. Even if they deserve to be brought into consideration in the universal theory of the purposiveness of things of nature, yet they belong to another [science], i.e. Metaphysics, and constitute no internal principle of natural science; as with the empirical laws of natural purposes in organised beings, it is not only permissible but unavoidable to use the teleological mode of judging as a principle of the doctrine of nature in regard to a particular class of its objects.

So to the end that Physics may keep within its own bounds, it abstracts itself entirely from the question, whether natural purposes are designed or undesigned; for that would be to meddle in an extraneous business, in Metaphysics. It is enough that there are objects, alone explicable according to natural laws which we can only think by means of the Idea of purposes as principle, and also alone internally cognisable as concerns their internal form, in this way. In order, therefore, to remove the suspicion of the slightest assumption, - as if we wished to mix with our grounds of cognition something not belonging to Physic at all, viz. a supernatural cause, - we speak in Teleology, indeed, of nature as if the purposiveness therein were designed, but in such a way that this design is ascribed to nature, i.e. to matter... Hence we speak quite correctly in Teleology, so far as it is referred to Physics, of the wisdom, the economy, the forethought, the beneficence of Nature, without either making an intelligent being of it, for that would be preposterous; or even without presuming to place another intelligent Being above it as its Architect, for that would be presumptuous...

But now why is it that Teleology usually forms no proper part of theoretical natural science, but is regarded as a propaedeutic or transition to Theology? This is done in order to restrict the study of nature, mechanically considered, to that which we can so subject to observation or experiment that we are able to produce it ourselves as nature does, or at least by similar laws. For we see into a thing completely only so far as we can make it in accordance with our concepts and bring it to completion.

Michael Rohlf, in his article, Immanuel Kant, in the Stanford Encyclopedia of Philosophy, explains why Kant was forced to postulate a special cognitive faculty, the reflecting power of judgment, in order to integrate the fundamental disconnect in his worldview between the phenomenal (which science deals with) and the noumenal (which religion and morality deal with):

If science applies only to appearances, while moral and religious beliefs refer to things in themselves or "the supersensible," then how can we integrate these into a single conception of the world that enables us to transition from the one domain to the other? Kant's solution is to introduce a third a priori cognitive faculty, which he calls the reflecting power of judgment, that gives us a teleological perspective on the world. Reflecting judgment provides the concept of teleology or purposiveness that bridges the chasm between nature and freedom, and thus unifies the theoretical and practical parts of Kant's philosophy into a single system (5:196–197).

While Kant treated the argument from design for the existence of God with great respect, he also maintained that mere empirical phenomena, by themselves, could never furnish us with a concept such as the idea of God. For Kant, "God" and "free will" were fundamental, albeit unproveable, principles that were essential to his version of "practical reason."

In section 7.2 of his article on Kant, Rohlf goes on to describe how in Kant's view, the power of reflecting judgment could take us to an Intelligent Designer of Nature:

In the Critique of the Power of Judgment, Kant discusses four main ways in which reflecting judgment leads us to regard nature as purposive: first, it leads us to regard nature as governed by a system of empirical laws; second, it enables us to make aesthetic judgments; third, it leads us to think of organisms as objectively purposive; and, fourth, it ultimately leads us to think about the final end of nature as a whole.

First, reflecting judgment enables us to discover empirical laws of nature by leading us to regard nature as if it were the product of intelligent design (5:179–186). We do not need reflecting judgment to grasp the a priori laws of nature based on our categories, such as that every event has a cause. But in addition to these a priori laws nature is also governed by particular, empirical laws, such as that fire causes smoke, which we cannot know without consulting experience... Since this principle only regulates our cognition but is not constitutive of nature itself, this does not amount to assuming that nature really is the product of intelligent design, which according to Kant we are not justified in believing on theoretical grounds. Rather, it amounts only to approaching nature in the practice of science as if it were designed to be understood by us. We are justified in doing this because it enables us to discover empirical laws of nature. But it is only a regulative principle of reflecting judgment, not genuine theoretical knowledge, that nature is purposive in this way.

Second, Kant thinks that aesthetic judgments about both beauty and sublimity involve a kind of purposiveness, and that the beauty of nature in particular suggests to us that nature is hospitable to our ends... Although it is only subjective, the purposiveness exhibited by natural beauty in particular may be interpreted as a sign that nature is hospitable to our moral interests (5:300)...

Third, Kant argues that reflecting judgment enables us to regard living organisms as objectively purposive, but only as a regulative principle that compensates for our inability to understand them mechanistically, which reflects the limitations of our cognitive faculties rather than any intrinsic teleology in nature. We cannot understand organisms mechanistically because they are "self-organizing" beings, whose parts are "combined into a whole by being reciprocally the cause and effect of their form" (5:373–374)... [S]ince ... we can only think of organisms teleologically, which excludes mechanism, Kant ... says that we must think of both mechanism and teleology only as regulative principles that we need to explain nature, rather than as constitutive principles that describe how nature is intrinsically constituted (5:410ff.).

Fourth, Kant concludes the Critique of the Power of Judgment with a long appendix arguing that reflecting judgment supports morality by leading us to think about the final end of nature, which we can only understand in moral terms, and that conversely morality reinforces a teleological conception of nature. Once it is granted on theoretical grounds that we must understand certain parts of nature (organisms) teleologically, although only as a regulative principle of reflecting judgment, Kant says we may go further and regard the whole of nature as a teleological system (5:380–381). But we can regard the whole of nature as a teleological system only by employing the idea of God, again only regulatively, as its intelligent designer...

Thus Kant argues that although theoretical and practical philosophy proceed from separate and irreducible starting points — self-consciousness as the highest principle for our cognition of nature, and the moral law as the basis for our knowledge of freedom — reflecting judgment unifies them into a single, teleological worldview that assigns preeminent value to human autonomy.

C. How Methodological Naturalism became accepted as a rule of scientific methodology in the late 19th century

What rules of science were accepted by scientists before the 19th century?

The Great Wave off Kanagawa, by Katsushika Hokusai (1760–1849). Circa 1829-32. Number 1 in the series, Thirty-six Views of Mount Fuji. Image courtesy of Wikipedia. The rise of methodological naturalism in the nineteenth century was due to a confluence of several factors - or what might be called a "perfect storm," like the one pictured above.

One of the claims made at the Dover trial in 2005 was that methodological naturalism has a long and venerable history, and that it has been recognized for centuries as part and parcel of the way in which science should be done. During the course of my investigations, however, I uncovered a very different story. To be sure, scientists have accepted for well over 2,000 years that appealing to the tenets of some revealed religion is not an appropriate way to resolve scientific questions. This is what I referred to as principle (a) in Part A above, and it's universally accepted. But as I pointed out, principle (a) is perfectly consistent with natural theology, or the quest to arrive at a knowledge of God (a supernatural Being) on the basis of observed phenomena, rather than revealed religion.

Additionally, scientists have long recognized that they should avoid invoking supernaturalistic explanations when attempting to account for observed phenomena, until natural explanations have been eliminated as inadequate. But as I explained above, that's not methodological naturalism. As I remarked in Part A above in my discussion of principle (d), that's just a principle of scientific prudence: first, look for natural explanations before you appeal to supernatural ones. Methodological naturalism goes much further than this: it says that while you are doing science, you are not allowed to invoke the supernatural at all.

Principle (e), which stipulates that scientists should avoid appealing to miracles when attempting to account for empirical phenomena, was invoked back in the Middle Ages, but not in an anti-religious sense. At that time, the scope of science was confined to regular phenomena (as per principle (c)), so invoking miracles to account for these would have been methodologically inappropriate. And as I pointed out in Part A above, showing that an observed phenomenon is not miraculous entails that it is explicable in naturalistic terms, but it still fails to eliminate the supernatural as an ultimate explanation.

The long-accepted claim that science can be defined as the systematic study of physical phenomena goes back well over 2,000 years. (It can be found, for example, in Aristotle's Physics.) This is equivalent to principle (b) in Part A above, which as we saw is a very modest claim, which says absolutely nothing about whether science is competent to explain all of the physical phenomena we encounter in the natural world. Nor does it tell us whether science is capable of explaining physical phenomena without recourse to the supernatural.

During my historical researches, I also encountered scientists who endorsed the claim that science should confine itself to the study of either regular natural phenomena or replicable natural phenomena. In other words, these scientists espoused principle (c), which, as we saw above, fails to rule out appeals to supernatural explanations, and says nothing regarding the competence of science to account for the entire range of natural phenomena.

Principle (f), which states that scientists should always look for natural proximate causes of physical phenomena, was upheld by some medieval scientists, such as Jean Buridan and Nicolas Oresme. But at that time, the scope of science was confined to regular phenomena as per principle (c), so the principle could never have been invoked to argue that the entire range of natural phenomena (including singular events, such as prodigies of Nature) could be explained without recourse to the supernatural. What's more, these same medieval philosophers freely invoked God as the ultimate cause of physical phenomena, in their scientific writings.

Principle (g), which states that scientists should confine themselves to natural causes, when attempting to account for physical phenomena, was not, as far as I can tell, upheld by any scientist until the late eighteenth century. And as I pointed out in Part A above, even if principle (g) were generalized to cover the entire range of physical phenomena, it would still suffer from one fatal defect, from the viewpoint of a methodological naturalist: it neglects to assert the sufficiency of natural explanations, and thus fails to establish science as an autonomous discipline. For instance, even a supernaturalist could uphold principle (g), while still maintaining that observed phenomena require a deeper, metaphysical explanation in terms of some underlying non-physical Cause. That sounds innocuous, but it leaves the natural world vulnerable (in principle) to supernatural interference, and thus fails to guarantee the autonomy of science.

My investigations led me to conclude that methodological naturalism proper, defined in the way I proposed above (in principle (h)), is of relatively recent origin: as a principle of established scientific practice, it goes back no further than the nineteenth century.

Origins of Methodological Naturalism

Historian of science and medicine Professor Ronald Numbers, photographed at the 2008 History of Science Society conference, on 8 November 2008. Image courtesy of Ragesoss and Wikipedia.

An essay by the acclaimed historian of science, Professor Ronald Numbers, entitled, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, ed. by David C. Lindberg and Ronald L. Numbers, Chicago: University Of Chicago Press, 2003) is widely cited by opponents of Intelligent Design in support of the claim that methodological naturalism, as a basic principle for doing good science, goes back centuries - in fact, as far back as the late Middle Ages. For an example of how Numbers' essay is seen as a lynchpin in the skeptics' arsenal, see this post entitled, On the Origins of Methodological Naturalism (March 20, 2006) by Nick Matzke on Panda's Thumb.

Imagine my surprise, then, when I came across the following passage in Numbers' essay:

No single event marks the transition from godly natural philosophy to naturalistic modern science, but sometime between roughly the mid–eighteenth and mid–nineteenth centuries students of nature in one discipline after another reached the conclusion that, regardless of one's personal beliefs, supernatural explanations had no place in the practice of science. As we have seen, natural philosophers had often expressed a preference for natural causes, but few, if any, had ruled out appeals to God. In contrast, virtually all scientists (a term coined in the 1830s but not widely used until the late nineteenth century), whether Christians or non-Christians, came by the latter nineteenth century to agree that God talk lay beyond the boundaries of science.
(Ronald L. Numbers, 2003. "Science without God: Natural Laws and Christian Beliefs." In When Science and Christianity Meet, edited by David C. Lindberg and Ronald L. Numbers. Chicago: University Of Chicago Press, p. 272.)

I was even more surprised to see that Dr. Steven Schafersman, an American geologist and current President of Texas Citizens for Science, reached the same conclusion in his 1996 essay, Naturalism is an Essential Part of Science and Critical Enquiry (see here for a 1997 revision). I shall quote an excerpt from the 1996 version:

Naturalism did not exist as a philosophy before the nineteenth century, but only as an occasionally adopted and non-rigorous method among natural philosophers. It is a unique philosophy in that it is not ancient or prior to science, and that it developed largely due to the influence of science. Naturalism begins with Galileo and Isaac Newton, who began to explain nature by theoretical and experimental descriptions of matter and their motions. The outstanding success of this method led others to emulate them, and a comprehensive understanding of the universe was initiated. Galileo and Newton were not naturalists; they did not hesitate to attribute supernatural causes to things that they thought could not be explained by natural causes. Until the late eighteenth century, most scientists agreed with them, but the influence of the Enlightenment led scientists, such as Antoine Laurent Lavoisier, Pierre Simon de Laplace, and James Hutton to abandon all supernatural explanations in favor of natural ones. Biology was the last science to be so treated, by Jean Baptiste Lamarck and Charles Darwin. I am convinced that each of these men intentionally tried to be the Newton of his day--and science--by finding purely natural laws to explain natural processes and objects.

Under the influence of philosophers John Herschel and William Whewell, methodological naturalism was systematized and promulgated, so that, by the end of the nineteenth century, methodological naturalism was embedded in science. Naturalism as a necessary part of science thus developed gradually as science developed gradually with the practice and understanding of scientists. Appreciation of the hypothetico-deductive method and empirical-skeptical testing of hypotheses required naturalism, since legitimate, scientific supernatural predictions cannot be made or supernatural conjectures tested. Holdout scientists who persisted in using supernatural explanations were gradually abandoned intellectually by their students and colleagues, and they eventually died with no successors. There was never a single moment or event when supernaturalism was evicted from the structure of science and naturalism locked in. However, by the turn of the twentieth century, supernaturalism had been methodologically eliminated and the scientific method came to be identified as naturalistic. The last legitimate creationist scientists died around this time, and creationist pseudoscience was soon to be born. Thus, methodological naturalism became historically an essential part of science.

Ontological naturalism developed from this methodological naturalism.

According to both Professor Numbers and Schafersman, then, naturalism gradually became an entrenched part of scientific methodology between the late eighteenth and late nineteenth centuries. Now that's our real watershed interval. But how did it happen?

My research has led me to conclude that no branch of science actually adopted methodological naturalism before 1830, and that the triumph of methodological naturalism, which took place over a 44-year time period from 1830 to 1874, was chiefly due to a confluence of seven factors (a "perfect storm", if you will):

(i) a mechanical philosophy of Nature, in which the behavior of any object, and indeed the cosmos itself, could be wholly explained in terms of the mathematical laws governing the interactions of its parts;

(ii) widespread scientific acceptance of scientific determinism, partly because the French astronomer Laplace had shown that the solar system could maintain its stability without the need for any supernatural intervention, but principally because he had asserted in striking fashion that an intellect possessing perfect knowledge of the positions of each and every particle in the universe, as well as the forces acting on each particle, would be able to predict the future perfectly;

(iii) a growing acceptance of reductionism, as it became apparent that living things were composed of the same elements as non-living matter, and that they functioned according to principles that could be described in the language of physics and chemistry;

(iv) the successful discrediting of the doctrine of vitalism in biology;

(v) the increasing prevalence of the belief that the only genuine kind of scientific explanation is one which makes appeals to physical laws;

(vi) a belief, championed by some "progressive" members of the Church of England clergy, that since the laws of Nature were God's edicts, they were therefore tantamount to promises on His part, which God, who does not lie, cannot break (see Titus 1:2); and finally,

(vii) a growing acceptance, in scientific circles, of the causal closure of the material world, leaving no room for an immaterial agent (e.g. God or the soul) to intervene.

Where does the Intelligent Design movement stand on these issues?

The reader might be wondering: where does Intelligent Design theory stand on all these issues?

Mechanism

The attitudes of Intelligent Design proponents vary considerably concerning the question of whether a mechanical philosophy of Nature is an adequate one. Some ID proponents adopt a mechanistic philosophy of Nature; others prefer a more Aristotelian view; still others, a Platonic view, or even a Pythagorean view. All Intelligent Design advocates would agree, however, that the components of the cell can be described in mechanistic terms. They are indeed molecular machines.

Determinism

Off-hand, I don't know of any Intelligent Design proponents who are scientific determinists. (A few are theological determinists, but that's another matter.) However, I would like to point out in passing that the empirical criteria used by ID theorists in order to identify a system or pattern found in Nature as the work of an intelligent agent, would work equally well, even if this agent's behavior were completely determined by its body chemistry. I discuss this question at further length in my post, The four tiers of Intelligent Design – an ecumenical proposal. I should mention that I'm an advocate of libertarian free will, for reasons I have explained in my post, Battle of the two Elizabeths: are free will and physical determinism compatible?. See also my post, Is free will dead?.

Reductionism

As regards reductionism, Intelligent Design advocates are united on two essential points: they believe that a high degree of complex specified information - in particular, prescriptional information such as the DNA code and a living thing's genetic program - is a characteristic feature of biological life; and they believe that human thought is inherently open-ended, and transcends computer algorithms. You can't put the human mind in a box.

Vitalism

Vitalism is a successfully discredited doctrine; and I don't know of any Intelligent Design advocate who espouses it today.

Must all scientific explanations invoke physical laws?

Intelligent Design proponents would strongly oppose the claim that the only legitimate kind of scientific explanation is one which invokes a physical law. On the contrary, explaining an artifact as the work of an intelligent agent is perfectly legitimate, even if we have no idea of the agent's body chemistry or modus operandi, and are therefore unable to explain how the agent makes things, let alone how the agent thinks up new designs. However, ID advocates would agree that there must be rigorous empirical criteria specifying the standards by which a pattern in Nature can be scientifically shown to be the work of an intelligent agent. That's why Professor William Dembski has done so much work on the Explanatory Design Filter.

Are the laws of Nature equivalent to promises made by God?

Intelligent Design proponents are very wary of attempts to formulate any grand theological principles which limit the freedom of God. ID proponents are particularly skeptical of a priori arguments purporting to demonstrate that God cannot break His own laws. The very notion seems absurd; for the laws of the cosmos are nothing more than statements which describe the regular way in which bodies interact with one another, in accordance with God's general will, but nothing prevents God from making rare exceptions for His own special reasons.

The causal closure of the physical

Finally, Intelligent Design proponents are leery of any arguments purporting to demonstrate the causal closure of the physical. Such arguments tend to be circular: they assume what they set out to prove.

Below, I shall attempt to undertake a brief historical sketch, showing how the principle of methodological naturalism came to be accepted in the scientific world. But before I do, I'd like offer my readers an example of a piece of writing that explicitly appealed to the supernatural, in a mid-nineteenth century science journal. "Which one?" you ask. Chances are, it's probably on your living room table. Yes, I'm talking about Scientific American.

A Short Proof that Methodological naturalism was still not entrenched scientific practice, as late as the mid-nineteenth century

Cover of the September 1848 issue of Scientific American. Image courtesy of Wikipedia.

Rufus Porter (1792-1884) was the founder of Scientific American magazine, whose first issue, in 1842, included an essay he wrote on "Rational Religion," in which he declared that as "rational creatures," we should "be ever ready to acknowledge God as our Creator and daily Preserver," and that we can know that petitionary prayer is rational "even without the aid of revelation." Curiously, this issue is no longer available on the Scientific American Web site. I wonder why. Allow me to quote a paragraph:

First, then, let us, as rational creatures, be ever ready to acknowledge God as our Creator and daily Preserver; and that we are each of us individually dependant on his special care and good will towards us, in supporting the wonderful action of nature which constitutes our existence; and in preserving us from the casualties, to which our complicated and delicate structure is liable. Let us also, knowing our entire dependence on Divine Benevolence, as rational creatures, do ourselves the honor to express personally and frequently, our thanks to him for his goodness; and to present our petitions to Him for the favours which we constantly require. This course is rational, even without the aid of revelation: but being specially invited to this course, by the divine word, and assured of the readiness of our Creator to answer our prayers and recognize our thanks, it is truly surprising that any rational being, who has ever read the inspired writings should willingly forego this privilege, or should be ashamed to be seen engaged in this rational employment, or to have it known that he practices it.

Porter wrote those words in the very first issue of a science magazine that he founded. Looks like someone forgot to tell him about "methodological naturalism."

A short history of methodological naturalism

http://sheekh-3arb.org/library/books/up_coll/WHEN_SCIN_CHRIS.pdf

In the account below, I've decided to provide a parallel narrative, covering seven different science-related fields, of the key events occurring in (and shortly before) this period:

1. Astronomy.
2. Physics and chemistry.
3. Geology.
4. Medicine.
5. Biology.
6. Psychology.
7. Science and Religion.

Some readers may be wondering why France led Europe in the trend towards methodological naturalism. I would refer them to a book entitled Atheism in France, 1650-1729 by Alan Charles Kors (published by Princeton University Press). In this erudite work, Professor Kors argues that bickering between rival schools of Christian theologians in the late seventeenth and early eighteenth centuries was what ultimately gave rise to atheism among France's intellectual elite. In what Kors describes as the "great fratricide", theologians from bitterly competing schools of Aristotelian, Cartesian, and Malebranchist Christian thought attempted to refute each other's proofs of God, and to depict the ideas of their theological opponents as atheistic. This caught the attention of France's reading public, causing many intellectuals to doubt the existence of God. France is to this day an atheistic country.

1. Astronomy

The nebular hypothesis, showing an artist's concept of a protoplanetary disk. Image courtesy of NASA and Wikipedia.

(a) Pierre Laplace dispenses with Newton's "God of the gaps"

The system of physics developed by Sir Isaac Newton (1642-1727) was mathematically elegant, but at the same time explicitly theistic: Newton was forced to postulate that Divine intervention was required from time to time, in order to keep the orbits of the planets stable. For the renowned French scientist Pierre-Simon de Laplace (1749-1827), who was also a notorious atheist, the elimination of Newton's God from physics would become a driving passion. During his lifetime, Laplace was largely successful in his endeavor. To quote from Laplace's Encyclopedia Britannica biography:

In 1773 he began his major lifework — applying Newtonian gravitation to the entire solar system — by taking up a particularly troublesome problem: why Jupiter's orbit appeared to be continuously shrinking while Saturn's continually expanded. The mutual gravitational interactions within the solar system were so complex that mathematical solution seemed impossible; indeed, Newton had concluded that divine intervention was periodically required to preserve the system in equilibrium. Laplace announced the invariability of planetary mean motions (average angular velocity). This discovery in 1773, the first and most important step in establishing the stability of the solar system, was the most important advance in physical astronomy since Newton. It won him associate membership in the French Academy of Sciences the same year.

(b) Laplace's nebular hypothesis

Towards the end of the eighteenth century, the French mathematician and astronomer Pierre-Simon de Laplace put forward a model for the origin of the solar system which is now known as the nebular hypothesis. Laplace was by no means the first to propose a nebular hypothesis: according to an article by Gregory Baker entitled, Emmanuel Swedenborg - An 18th century cosmologist (The Physics Teacher, October 1983, pp. 441-446), the Swedish thinker Emmanuel Swedenborg had proposed a similar theory back in 1734, but without incorporating Newton's methods or ideas into his model. In 1754, the philosopher Emmanuel Kant also proposed a nebular hypothesis, in his Universal Natural History and Theory of the Heavens, translated by W. Hustic (University of Michigan Press, Ann Arbor, 1969). However, what was distinctive about Laplace's hypothesis was its mathematical rigor. Laplace's theory eventually became very popular in the scientific world, but as Numbers points out in his narrative of the rise of methodological naturalism, its ability to explain the origin of the solar system in terms of laws meant that it could be construed atheistically, as its author intended:

... Laplace in 1796 proposed that the planets had been formed from the revolving atmosphere of the primitive Sun, which, as it cooled and contracted, had abandoned a succession of Saturn-like rings, which had coalesced to form the planets. On the occasion of a visit in 1802 to the country estate of Napoleon Bonaparte, Laplace entertained his host with an account of his so-called nebular hypothesis. When the French leader asked why he had heard no mention of God, Laplace supposedly uttered the much-quoted words "Sire, I have no need of that hypothesis." The only firsthand account of the exchange simply reports Napoleon's disappointment with Laplace's explanation that "a chain of natural causes would account for the construction and preservation of the wonderful system." Either way, there was no mistaking the impious message.
(Ronald L. Numbers, 2003. "Science without God: Natural Laws and Christian Beliefs." In When Science and Christianity Meet, edited by David C. Lindberg and Ronald L. Numbers. Chicago: University Of Chicago Press, p. 273.)

Despite its avowedly secular explanatory framework, the nebular hypothesis actually strengthened the argument from design to the existence of a Creator, as the argument's proponents adapted their strategy and used the existence of universal scientific laws as evidence for the existence of a wise Creator of the cosmos:

As more and more of the artifacts of nature, such as the solar system, came to be seen as products of natural law rather than divine miracle, defenders of design increasingly shifted their attention to the origin of the laws that had proved capable of such wondrous things. Many Christians concluded that these laws had been instituted by God and were evidence of His existence and wisdom. In this way, as John Le Conte (1818-91) of the University of California pointed out in the early 1870s, the cosmogony of Laplace helped to bring about a transformation in the application of the principle of design "from the region of facts to that of laws." The nebular hypothesis thus strengthened, rather than weakened, the argument from design, opening "before the mind a stupendous and glorious field for meditation upon the works and character of the Great Architect of the Universe."

Christian apologists proved equally adept at modifying the doctrine of divine providence to accommodate the nebular hypothesis. Instead of pointing to the miraculous creation of the world by divine fiat, a "special" providential act, they emphasized God's "general" providence in creating the world by means of natural laws and secondary causes. (Numbers, 2003, pp. 275-276.)

While the Laplacian nebular model was widely accepted in the 19th century, it later ran into a number of problems, the principal one being the angular momentum distribution between the Sun and planets. Laplace's nebular model was unable to explain why the planets have 99% of the angular momentum. Consequently, Laplace's theory of planet formation was largely abandoned at the beginning of the 20th century, and various alternative theories were put forward, none of which were very successful.

Recently, Laplace's nebular hypothesis has enjoyed something of a comeback, and astronomers currently accept a modern variant of Laplace's theory, known as the Solar Nebular Disk Model (SNDM) or simply the Solar Nebular Model. The new model was first developed by the Soviet astronomer Victor Safronov, whose book, Evolution of the Protoplanetary Cloud and Formation of the Earth and the Planets (Israel Program for Scientific Translations), was translated into English in 1972. Safronov's hypothesis was further elaborated by George Wetherill, who discovered that the Jovian protoplanets probably had discs of their own from which satellites formed, in close analogy to the solar system as a whole. Astronomers now believe that the Solar Nebular Disk Model explains not only the formation of planets in our solar system, but other solar systems as well.

Although Laplace rejected belief in the supernatural, he made no systematic attempt to develop a philosophy of science that excludes the supernatural from the domain of science. The first person to do this in the field of astronomy was, ironically, a devout Christian: Sir John Herschel, FRS (1792-1871), whose father, William Herschel, FRS (1738-1822), discovered the planet Uranus.

(c) Sir John Herschel's methodological naturalism in astronomy

In his 2003 essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, ed. by D. C. Lindberg and R. L. Numbers, Chicago: University Of Chicago Press), Ronald Numbers highlights the crucial event in his account of how anti-supernaturalism became entrenched in the field of astronomy: the publication of a book by an eminent astronomer which attempted for the first time to articulate the scientific method, from a scientist's perspective.

A Preliminary Discourse on the Study of Natural Philosophy (1830) by English astronomer John Herschel (1792-1871) was described by one scholar as "the first attempt by an eminent man of science to make the methods of science explicit." Frequently extrapolating from astronomy, the paradigmatic science of the time, Herschel asserted that sound scientific knowledge derived exclusively from experience — "the great, and indeed only ultimate source of our knowledge of nature and its laws" - which was gained by observation and experiment, "the fountains of all natural science." Natural philosophy and science (he used the terms interchangeably) recognized only those causes "having a real existence in nature, and not being mere hypotheses or figments of the mind." Although this stricture ruled out supernatural causes, Herschel adamantly denied that the pursuit of science fostered unbelief. To the contrary, he insisted that science "places the existence and principal attributes of a Deity on such grounds as to render doubt absurd and atheism ridiculous." Natural laws testified to God's existence; they did not make him superfluous. (Numbers, 2003, pp. 277-278.)

It should be noted here that if we accept Numbers' reading of Herschel, the principle he espouses here is not methodological naturalism, properly speaking - that is, the claim that natural causes are sufficient to account for all observed phenomena - but merely the lesser claim that scientists should confine themselves to natural causes when attempting to account for observed phenomena - in other words, principle (f) in Part A above, which as we saw says nothing about whether science is able to fully explain the entire range of natural phenomena.

2. Physics and chemistry

Clockwork Universe sculpture by Tim Wetherell, at Questacon, Canberra, Australia. Image courtesy of Ophelia O. and Wikipedia.

(a) How "Laplace's demon" strengthened belief in determinism

In his work, A Philosophical Essay on Probabilities (1814), the French mathematician and astronomer Pierre-Simon Laplace (1749-1827) put forward the first articulation of causal or scientific determinism:

We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at a certain moment would know all forces that set nature in motion, and all positions of all items of which nature is composed, if this intellect were also vast enough to submit these data to analysis, it would embrace in a single formula the movements of the greatest bodies of the universe and those of the tiniest atom; for such an intellect nothing would be uncertain and the future just like the past would be present before its eyes.

This intellect is often referred to as Laplace's demon, but Laplace himself did not use that term. However, Laplace's statement led to the widespread but incorrect belief that Newtonian physics logically entailed determinism. The work of John Earman and J. D. Norton has since shown that this is not the case.

In an essay entitled, Aspects of Determinism in Modern Physics, in Handbook of the Philosophy of Science. Volume 2: Philosophy of Physics (Volume editors: John Earman and Jeremy Butterfield. Handbook editors: Dov M. Gabbay, Paul Thagard and John Woods; North Holland, 2005, pp. 1369-1434), philosopher of science John Earman argues forcefully against the common view that Newtonian physics is deterministic.

Classical physics is widely assumed to provide a friendly environment for determinism. In fact, determinism must overcome a number of obstacles in order to achieve success in this setting. First, classical spacetime structure may not be sufficiently rich to support Laplacian determinism for particle motions. Second, even if the spacetime structure is rich, uniqueness can fail in the initial value problem for Newtonian equations of motion if the force function does not satisfy suitable continuity conditions. Third, the equations of motion that typically arise for classical particles plus classical fields, or for classical fi;elds alone, do not admit an initial value formulation unless supplementary conditions are imposed. Fourth, even in cases where local (in time) uniqueness holds for the initial value problem, solutions can break down after a finite time. (Earman, 2006, p. 1375.)

The simplest known example of indeterminism in Newtonian physics is the case of the dome, where a mass sits at the apex of a radially symmetrical dome. After remaining unchanged for an arbitrary time, it spontaneously moves in an arbitrary direction, with these indeterministic motions compatible with Newtonian mechanics. This case is described by philosopher of science J. D. Norton in his paper, The Dome: An Unexpectedly Simple Failure of Determinism, (prepared for the Symposium, "The Vagaries of Determinism and Indeterminism," PSA 2006: Philosophy of Science Association Biennial Conference, Vancouver, November 2006).

The Wikipedia article on Laplace's demon also mentions scientists who have critiqued the concept:

According to chemical engineer Robert Ulanowicz, in his 1986 book Growth and Development, Laplace's demon met its end with early 19th century developments of the concepts of irreversibility, entropy, and the second law of thermodynamics. In other words, Laplace's demon was based on the premise of reversibility and classical mechanics; however, under current theory, thermodynamics (i.e. real processes) are thought to be irreversible in practical terms (compared to the age of the universe, for instance).

In 2008, David Wolpert used Cantor diagonalization to disprove Laplace's demon. He did this by assuming that the demon is a computational device and showing that no two such devices can completely predict each other. If the demon were not contained within and computed by the universe, any accurate simulation of the universe would be indistinguishable from the universe to an internal observer, and the argument remains distinct from what is observable.

Even if determinism were true, it would not follow that the future behavior of the universe is predictable. To quote Earman again:

Since we are free to imagine demons with whatever powers we like, let us suppose that Laplace's Demon can ascertain the initial conditions of the system of interest with absolute mathematical precision. As for computational ability, let us suppose that the Demon has at its disposal a universal Turing machine. As impressive as these abilities are, they may not enable the Demon to predict the future state of the system even if it is deterministic... Thus, for most of the initial conditions the Demon encounters, ... the Demon must consult an Oracle in order to make a sure fire prediction...

The generalization of Turing's theorem by Rice [1953] shows that many questions about the behavior of a universal Turing machine in the unbounded future are recursively unsolvable, and these logical questions will translate into physical questions about the behavior of the particle in the unbounded future that the Demon cannot answer without consulting an Oracle. (Earman, 2006, pp. 1392-1393.)

Today, we can appreciate the limits of determinism, and distinguish between the notions of determinism and predictability, but many of the philosophical and mathematical concepts required to make such distinctions were not yet available in the nineteenth century. As a result, many educated people came to believe that science was wedded to the doctrine of determinism, and that believing in science meant giving up belief in free will. As we have seen in Part Three, Darwin was an outstanding example of this trend. Even by 1837, he was already a determinist, although he continued to believe in a God Who had created the laws of Nature.

(b) How the law of the conservation of energy strengthened belief in materialism

An engraving of Joule's apparatus for measuring the mechanical equivalent of heat, from Harper's New Monthly Magazine, No. 231, August, 1869. Image courtesy of Wikipedia.

See http://www.vigyanprasar.gov.in/scientists/HvonHelmholtz.htm

The law of the conservation of energy, which was first formulated in its modern form by Helmholtz in 1847, had a very profound impact on people's thinking, as regards the possibility of God interacting with the material world. But before we discuss the implications of this law, it might be useful for us to briefly review its history.

How the law of the conservation of energy was established

The idea that energy is a conserved quantity has quite a long history, going back to Gottfried Wilhelm Leibniz (1646-1716), who noticed that kinetic energy was conserved in systems where there is no friction. However, Leibniz's observations were unable to explain what happened in inelastic collisions, where kinetic energy was lost.

In 1837, in a paper entitled Uber die Natur der Warme, which was published in the Zeitschrift fur Physik, Karl Friedrich Mohr put forward one of the first general expressions of the idea of the conservation of energy, when he wrote that "besides the 54 known chemical elements there is in the physical world one agent only, and this is called Kraft [energy or work]. It may appear, according to circumstances, as motion, chemical affinity, cohesion, electricity, light and magnetism; and from any one of these forms it can be transformed into any of the others."

The notion that idea that heat is a form of kinetic energy was first suggested by Count Rumford (Benjamin Thompson) in 1798. However, the mechanical equivalence principle, which states that heat and work are equivalent was first proposed by Julius Robert von Mayer in 1842, and independently by James Prescott Joule in 1843. Similar work was carried out by the Danish physicist Ludwig A. Colding from 1840-1843. Unfortunately, Colding's work achieved little recognition outside his native country.

Joule's very precise measurements on the equivalence of work and heat played a pivotal role in establishing the kinetic theory of heat, at the expense of the caloric theory, which said that heat could neither be created nor destroyed. In 1845, Joule published a paper entitled "The Mechanical Equivalent of Heat", in which he specified a numerical value for the amount of mechanical work required to produce a unit of heat. Joule had carefully experimented on the amount of mechanical work generated by friction needed to raise the temperature of a pound of water by one degree Fahrenheit and found a consistent value of 772.24 foot pound force (in SI units, 4.1550 Joules per calorie). (Joule was measuring what we would now call the specific heat capacity of water.) Joule maintained that heat and motion were mutually interchangeable, and that a given amount of work would always generate the same amount of heat.

In 1847, Hermann von Helmholtz published what is considered the first definitive declaration of the law of the conservation of energy, in a treatise entitled, Uber die Erhaltung der Kraft (On the Conservation of Force). Although William Robert Grove had made a similar proposal earlier in 1844, the general modern acceptance by scientists of the principle stems from the publication of Helmholtz's treatise. Helmholtz had arrived at this law as a result of reading Joule's publications, although he eventually gave credit to both Joule and von Mayer for their work. Helmholtz also drew upon the work of Sadi Carnot and Emile Clapeyron.

The law of conservation of energy can also be expressed by saying that the energy of an isolated system is constant. The first law of thermodynamics is a version of the law of conservation of energy, specialized for thermodynamical systems. The first explicit statement of this law was made by Rudolf Clausius in 1850. Referring to cyclic thermodynamic processes, he wrote: "In all cases in which work is produced by the agency of heat, a quantity of heat is consumed which is proportional to the work done; and conversely, by the expenditure of an equal quantity of work an equal quantity of heat is produced."

The Presbyterian influence on thermodynamics

A review by Bruce Hunt of The Science of Energy: A Cultural History of Energy Physics in Victorian Britain by Crosbie Smith (University of Chicago Press, 1998) highlights the influence that a group of scientists of a similar religious view exerted on the history of physics in 19th century Britain:

Many readers will be surprised when, after a brief introduction, Smith plunges into a detailed account of 19th-century Scottish Presbyterianism. What could the theology of Thomas Chalmers, the "Disruption" of 1843 or the rise of an "incarnationalist" view of Christ have to do with the science of energy? Quite a lot, as Smith soon shows. The science of energy was largely created by a circle of Scottish scientists and engineers, led by William Thomson [Lord Kelvin - VJT], Maxwell, Tait and Macquorn Rankine, who were deeply imbued with Presbyterian doctrines. Smith argues persuasively that their ideas about energy and its dissipation were shaped by a characteristically Presbyterian belief that amid a fallen and decaying physical world, men had a responsibility to take God's gifts and use them well. Their new science of energy would provide a middle path between Biblical literalism and evolutionary materialism; it would be Christian yet progressive and well in tune with the rising industry of Glasgow and Manchester.

Theological implications of the law of conservation of energy

From its inception, the law of conservation of energy exerted a striking influence on philosophical thought. What was interesting, however, was that believers and unbelievers were able to interpret it very differently. We can see this most clearly if we compare its impact on the thinking of two scientists whose work played an important part in securing public acceptance of the law in the scientific world: Hermann von Helmholtz and James Joule.

For Hermann von Helmholtz, the law of the conservation of energy only served to confirm him in his materialism. As Michel Meulders notes in his recent book, Helmholtz: From Enlightenment to Neuroscience (MIT Press, 2010), Helmholtz was a very profound philosophical thinker who repeatedly invoked Newton's laws of physics in his 1847 treatise, On the Conservation of Force, which attempted to systematically explain all natural changes in terms of blind mechanical forces:

The treatise On the Conservation of Force was preceded by an introduction on the transformation of natural forces, which Helmholtz presented as a purely physical essay but which was in reality a metaphysical theorum of the philosophy of science and a brilliant review of his own convictions concerning natural science. He began with two principles: first, "that it could not be possible by the effects of any form of combination of natural bodies to obtain unlimited work"; and second, "that all natural activity could be reduced to attractive and repulsive forces of which the intensity depends only on the distance apart of forces which act on each other." So Helmholtz started from the beginning that perpetual motion was impossible and that the forces he cited in his treatise were those of Newton. (2010, p. 76.)

For Helmholtz, to understand nature meant reducing natural phenomena to inalterable forces of attraction and repulsion depending on the distance between the active elements. On the basis of his experimental prerequisities - the impossibility of perpetual motion and reliance on Newton's forces - he deduced the key principle of the conservation of force, which he confronted in the rest of his treatise with empirical data and rules derived from experimental physics. (2010, p. 82.)

[Helmholtz] worked "as if" almighty science was capable of resolving everything, and in so doing he subtly reinforced the credibility of his physical model of the world... He never claimed to be an atheist but only a materialist out of respect for the scientific method. (2010, p. 75.)

On the other hand, James Joule, whose work had influenced Helmholtz, was a deeply religious man, who regarded science as a way of knowing God the Creator: "After the knowledge of, and obedience to, the will of God, the next aim must be to know something of His attributes of wisdom, power and goodness as evidenced by His handiwork." Indeed, Joule was one of 717 scientists who signed a remarkable manifesto entitled, The Declaration of Students of the Natural and Physical Sciences, issued in London in 1864, which stated that "it is impossible for the Word of God, as written in the book of nature, and God's Word written in Holy Scripture, to contradict one another."

The two scientists' views on the theological implications of the law of conservation of energy were also strikingly different: for Helmholtz, it only served to confirm him in his materialism, whereas for Joule, it confirmed his belief that the order in the universe is maintained by laws created by a wise God:

"Thus it is that order is maintained in the universe - nothing is deranged, nothing ever lost, but the entire machinery, complicated as it is, works smoothly and harmoniously. And though, as in the awful vision of Ezekiel, 'wheel may be within wheel,' and everything may appear complicated and involved in the apparent confusion and intricacy of an almost endless variety of causes, effects, conversions and arrangements, yet is the most perfect regularity preserved - the whole being governed by the sovereign will of God."
(J.P. Joule in a brief autobiography written in January 1863, published in Memoirs and Proceedings of the Manchester Literary and Philosophical Society, vol. LXXV (1930–1931), no. 8, p. 110. See also H.J. Steffens, James Prescott Joule and the Concept of Energy, Folkestone, Dawson, 1979, p. 134.)

For the general public, however, the law of the conservation of energy had a corrosive effect on people's faith, as it seemed to leave no room for God to intervene in the natural world. The dualistic concept of the human soul being able to interact with matter was also rendered problematic, for how could it do so without adding to the energy of the human body when interacting with it?

(c) The second law of thermodynamics

According to the Second Law of Thermodynamics, the entropy of a closed system tends to increase over time. Ice melting in a warm room is a common example of increasing entropy. In this case, the closed system can be regarded as the warm room as a whole, which contains the glass of ice water. Image courtesy of Jon Sullivan and Wikipedia.

The Second Law of Thermodynamics, discovered by Rudolph Clausius in 1850 and independently by Lord Kelvin in 1851. In Clausius' original formulation, it read: "No process is possible whose sole result is the transfer of heat from a body of lower temperature to a body of higher temperature." Kelvin's formulation, "No process is possible in which the sole result is the absorption of heat from a reservoir and its complete conversion into work," was shown to be equivalent to Clausius' version.

In practical terms, the second law declares the impossibility of building perpetual motion machines.

The second law also has implications for the universe as a whole. In a presentation at the Philosophical Society of Zurich on April 24, 1865, Rudolph Clausius concluded his lecture with the words: "The entropy of the universe tends to a maximum." According to the second law, the entropy of any isolated system, such as the entire universe, never decreases.

At first sight, the Second Law of Thermodynamics, with its picture of a universe that is running down, appears to conflict with the first, which tells us that the total energy in the universe always remains constant. However, what the Second Law of Thermodynamics states is that the total useful energy in the universe (i.e. the energy that is available for doing work) will decrease over time.

The second law of thermodynamics has obvious implications regarding the causal closure of the universe. Miracles would seem to be excluded by this law, as they involve a reduction in entropy. It might be argued in response that (i) a Creator who sets up the laws of the cosmos is perfectly free to violate those laws whenever He wishes; and (ii) in any case, a Creator could surely reduce entropy locally while ensuring that for the universe as a whole, it continued to increase. However, as I'll explain at further length in section 7 below, by the mid-nineteenth century, belief in a Creator Who violated His own laws was becoming theologically unfashionable in Victorian society, thanks largely to the work of the mathematician and theologian Baden Powell, who argued that the laws of Nature were tantamount to promises that God could not break.

The second law has other theological implications. It can be used to argue that since the universe is running down, it must have had a beginning. It can also be used to justify pessimism and despair. As Gregory Hill and Kerry Thornley put it in their Principia Discordia (1965): "The tendency for entropy to increase in isolated systems is expressed in the second law of thermodynamics — perhaps the most pessimistic and amoral formulation in all human thought."

Both of the foregoing arguments, however, presuppose that the universe is finite - a point was made by Lord Kelvin himself in his 1862 paper, On the Age of the Sun's Heat:

The second great law of thermodynamics involves a certain principle of irreversible action in Nature. It is thus shown that, although mechanical energy is indestructible, there is a universal tendency to its dissipation, which produces gradual augmentation and diffusion of heat, cessation of motion, and exhaustion of potential energy through the material universe. The result would inevitably be a state of universal rest and death, if the universe were finite and left to obey existing laws. But it is impossible to conceive a limit to the extent of matter in the universe; and therefore science points rather to an endless progress, through an endless space, of action involving the transformation of potential energy into palpable motion and thence into heat, than to a single finite mechanism, running down like a clock, and stopping for ever. It is also impossible to conceive either the beginning or the continuance of life, without an overruling creative power; and, therefore, no conclusions of dynamical science regarding the future condition of the earth can be held to give dispiriting views as to the destiny of the race of intelligent beings by which it is at present inhabited.
(Macmillan's Magazine, vol. 5 (March 5, 1862), pp. 388-393. From a reprint in Popular Lectures and Addresses, vol. 1, 2nd edition. In The Kelvin Library. Zapato Productions Intra­dimensional.)

In the 21st century, the notion of a finite universe no longer appears so shocking, and it now turns out that even if there is an infinite multiverse, it would still need to have had a beginning, as cosmologist Alexander Vilenkin of Tufts University in Boston acknowledged recently (see my online article, Vilenkin's verdict: "All the evidence we have says that the universe had a beginning." and Why physicists can't avoid a creation event by Tomas Quinton, 12 January 2012).

Useful book: http://books.google.co.jp/books?id=BBgXuy_D8WEC&pg=PA370&lpg=PA370&dq=Joule+God+conservation+of+energy&source=bl&ots=L4xlSiFsn-&sig=mnVpPZrCa-NtL-bd1Q1l_T1N4hs&hl=en&sa=X&ei=4HOMT7z0IcaZiAe-rIm4CQ&redir_esc=y#v=onepage&q=Joule%20God%20conservation%20of%20energy&f=false

3. Geology

The frontispiece from Charles Lyell's Principles of Geology (second American edition, 1857), showing the origins of different rock types. Image courtesy of Wikipedia.

(a) A French scientist (Count Buffon) argues for the exclusion of the supernatural from science, for the first time in modern history

Georges-Louis Leclerc de Buffon (1707-1788), also known as Count Buffon, was one of the first naturalists to argue that science should be wholly autonomous and free of any theological influence. Buffon is widely portrayed as a thorough-going naturalist. So it comes as a surprise when we read in Jacques Roger's book, Buffon: a life in natural history (Cornell University Press, 1997) that Buffon did not reject the historicity of the Biblical Flood, but merely wished to exclude it from the domain of science, because it was a miracle, which human reason was powerless to explain. Roger cites Buffon's own words on the subject:

"Whenever one is rash enough to try to explain theological truths through physical reasons, permits oneself to interpret the divine text of sacred books in purely human terms, or wants to apply one's reason to the will of the Most High and to the execution of His decrees, one necessarily falls into darkness and chaos."

The Flood was impossible to explain physically. It had to be seen as a miracle and nothing else; "above all bad physics [should] not be mixed with the purity of the Holy Book." (Roger, 1997, p. 101.)

Roger goes on to explain that Buffon's motivation in excluding miracles was to carve out an autonomous domain for human reason:

By excluding the biblical Flood from the physical history of the Earth, Buffon wanted to do more than indicate science's independence from theology. The Flood was physically inexplicable, but it was also a catastrophe, and Buffon refused, for reasons of method, to resort to such explanations: "The causes of rare, violent, and sudden effects must not concern us: they are not to be found in the ordinary workings of Nature. It is with effects that happen every day - the movements that succeed one another and that renew themselves without interruption - the constant and always repeated operations - that we must consider our causes and our reasons. In other words, "in order to judge what has happened and even what will happen, we have only to examine that which happens." Well before the geologists of the nineteenth century, Buffon rejected "catastrophism." He accepted only the "current causes," causes that we are able to observe at work in Nature. It was by excluding both miracles and catastrophes that natural history could really be natural. (Roger, 1997, p. 101.)

In his essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, ed. David C. Lindberg and Ronald L. Numbers, University Of Chicago Press, 2003) Ronald Numbers depicts Buffon was not even concerned with whether his naturalistic accounts were true:

Buffon called for an emphasis on the regularities of nature and a renunciation of all appeals to the supernatural. Those studying physical subjects, he argued, "ought as much as possible, to avoid having recourse to supernatural causes." Philosophers "ought not to be affected by causes which seldom act, and whose action is always sudden and violent. These have no place in the ordinary course of nature. But operations uniformly repeated, motions which succeed one another without interruption, are the causes which alone ought to be the foundation of our reasoning." Buffon professed not to care whether such explanations were true — so long as they appeared probable. A theist, though not a practicing Christian, Buffon acknowledged that the Creator had originally set the planets in motion, but considered the fact of no value to the natural philosopher. (Numbers, 2003, p. 273.)

Buffon also attempted to account for the origins of the solar system in naturalistic terms, proposing a method of creation of the planets which involved the collision of a comet with the sun. However, his account lacked mathematical rigor and was not very successful. He also proposed that the Earth was 75,000 years old, basing his figure on the cooling rate of a ball of iron tested at his Laboratory the Petit Fontenet at Montbard, France. This got him into hot water with the Sorbonne, so in order to avoid further problems, he issued a retraction.

Buffon also argued that life on earth had come about through the appearance of organic matter, which was generated by the action of heat on oily substances. In his day, such a view would have aroused little comment, as belief in spontaneous generation was still widespread. He was not an evolutionist, however: he believed that species were fixed, as shown by their inability to inter-breed. Buffon also argued, contrary to James Burnett (Lord Monboddo) that man and the apes were not related. He believed that the human race was only 6,000years old.

Ernst Mayr, in his work, The Growth of Biological Thought (1981, Cambridge: Harvard, p330) argues that Buffon had a pivotal influence on the history of evolutionary thinking, despite his mistaken belief in the fixity of species:

He was not an evolutionist, yet he was the father of evolutionism. He was the first person to discuss a large number of evolutionary problems, problems that before Buffon had not been raised by anybody.... he brought them to the attention of the scientific world.

Except for Aristotle and Darwin, no other student of organisms [whole animals and plants] has had as far-reaching an influence.

Drawing on Mayr's work, the Wikipedia biography of Buffon sums up his contribution to biology:

He brought the idea of evolution into the realm of science. He developed a concept of the "unity of type", a precursor of comparative anatomy. More than anyone else, he was responsible for the acceptance of a long-time scale for the history of the earth. He was the founder of biogeography. And yet, he hindered evolution by his frequent endorsement of the immutability of species. He provided a criterion of species, fertility among members of a species, that was thought impregnable.

The Scottish naturalist James Hutton (1726-1797) applied the concept of uniformitarianism in a systematic fashion to the science of geology, in his Theory of the Earth; or an Investigation of the Laws observable in the Composition, Dissolution, and Restoration of Land upon the Globe, which was read to the Royal Society of Edinburgh in 1785 and published in 1788. At the end of his lengthy work, Hutton declared:

[W]e have the satisfaction to find, that in nature there is wisdom, system, and consistency. For having, in the natural history of this earth, seen a succession of worlds, we may from this conclude that there is a system in nature; in like manner as, from seeing revolutions of the planets, it is concluded, that there is a system by which they are intended to continue those revolutions. [...] The result, therefore, of our present enquiry is, that we find no vestige of a beginning, – no prospect of an end.
(Hutton, James. Theory of the Earth with Proofs and Illustrations. Vol 1 and 2. Weinheim: H.R. Engelmann (J. Cramer) and Wheldon & Wesley, LTD., 1960.)

Despite the fact that it removed the need for a Creator, Hutton's theory was by no means an atheistic one - hence his reference to the "wisdom, system, and consistency" in Nature. As one of Hutton's eloquent defenders, John Playfair (1748–1819), pointed out, for Hutton the Earth, though perpetual, is ultimately maintained by God, for the author of nature "has not given laws to the universe, which, like the institutions of men, carry in themselves the elements of their own destruction. He has not permitted in His works any symptoms of infancy, or of old age, or any sign by which we may estimate either their future or their past duration." Or as Edmund Siderius puts it in a recent online essay entitled, God of Hutton, God of Kelvin: Religion, Eternity and the Age of the Earth (23 August 2011): "The world had obviously been created for the benefit of the things living upon it and for human beings in particular, and it would not have been fitting for a wise and omnipotent being to create it as anything other than eternal."

(b) Charles Lyell applies Herschel's methodological naturalism to the science of geology

Left: Marble bas-relief of Moses, in the U.S. House of Representatives, Washington D.C. Sculpture by Jean de Marco; photo by the Architect of the Capitol. Image courtesy of Wikipedia.
Right: British geologist Charles Lyell, Kt FRS. Painting by Alexander Craig, at the British Association meeting in Glasgow in 1840. Lyell revolutionized the science of geology in the 1830s with the publication of his book, Principles of Geology (1830-33). His avowed aim was to "free the science from Moses."

The next critical step occurred in 1830, when Sir John Herschel's methodological principles were applied by the British geologist Charles Lyell to the newly emerging science of geology, in a deliberate attempt to free the science "from Moses." As Ronald Numbers puts it in his essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, edited by David C. Lindberg and Ronald L. Numbers, Chicago: University Of Chicago Press, 2003):

When students of Earth history, many of them Protestant ministers, created the new discipline of geology in the early nineteenth century, they consciously sought to reconstruct Earth history using natural means alone. By the 1820s virtually all geologists, even those who invoked catastrophic events, were eschewing appeals to the supernatural. When the British geologist Charles Lyell (1797-1875) set about in the early 1830s to "free the science from Moses," the emancipation had already largely occurred. Nevertheless, his landmark Principles of Geology (1830-33) conveniently summed up the accepted methods of doing geology, with the subtitle, Being an Attempt to Explain the Former Changes of the Earth's Surface, by Reference to Causes Now in Operation, conveying the main point. As Lyell described his project to a friend, it would in good Herschelian fashion "endeavour to establish the principles of reasoning in the science," most notably the idea "that no causes whatever have from the earliest time to which we can look back to the present ever acted but those now acting & that they never acted with different degrees of energy from that which they now exert." (Numbers, 2003, p. 278.)

However, Lyell's method of doing geology opened up a theological can of worms: if currently existing natural processes were sufficient to explain everything that had happened during the history of the Earth, then what room did this leave for God? After all, one could always postulate that the Earth had existed forever. (Back in the 1830s, there was no good scientific evidence to show that the Earth had ever had a beginning.) Lyell himself recognized this implications of his uniformitarian principle, and wrote about them in a letter to George Poulett Scrope (dated 14th June 1830), an excerpt from which is quoted by authors David Catchpoole and Tas Walker of creation.com in their online article, Charles Lyell's hidden agenda — to free science "from Moses" (19 August 2009):

I am sure you may get into Q.R. [Quarterly Review] what will free the science from Moses, for if treated seriously, the [church] party are quite prepared for it. A bishop, Buckland ascertained (we suppose [Bishop] Sumner), gave Ure a dressing in the British Critic and Theological Review. They see at last the mischief and scandal brought on them by Mosaic systems .... Probably there was a beginning — it is a metaphysical question, worthy of a theologian — probably there will be an end. Species, as you say, have begun and ended — but the analogy is faint and distant. Perhaps it is an analogy, but all I say is, there are, as Hutton said, 'no signs of a beginning, no prospect of an end' .... All I ask is, that at any given period of the past, don't stop inquiry when puzzled by refuge to a 'beginning,' which is all one with 'another state of nature,' as it appears to me. But there is no harm in your attacking me, provided you point out that it is the proof I deny, not the probability of a beginning...

Lyell was delighted that clergymen were espousing his new geological methodology, and naturally he wanted to conciliate them by refraining from saying anything that would offend their beliefs. Hence his diplomatic advice to Scrope about what to say if the question of the Earth's beginning ever arose in scientific correspondence.

Lyell made no attempt, however, to explain the origin of biological species (especially human beings) in terms of secondary causes. Lyell was, as Numbers notes in his above-cited essay, a communicant of the Church of England.

4. Medicine

Left: A 19th century automaton. CIMA museum (Centre International de la Mecanique d'Art), Sainte-Croix, Switzerland. Image courtesy of Rama and Wikipedia.
Right: A 19th century Japanese tea serving doll, and its internal mechanism. Tokyo National Science Museum. Image courtesy of Wikipedia.

(a) Julien Offray de La Mettrie is denounced in France for promoting materialism in medicine

An article in Encyclopedia Britannica summarizes the significant role played by Julien Offray de La Mettrie in the history of modern materialism:

La Mettrie obtained a medical degree at Reims, studied medicine in Leiden under Hermann Boerhaave (some of whose works he translated into French), and served as surgeon to the French military. A personal illness convinced him that psychic phenomena were directly related to organic changes in the brain and nervous system. The outcry following publication of these views in Histoire naturelle de l'ame (1745; "Natural History of the Soul") forced his departure from Paris. The book was burned by the public hangman. In Holland La Mettrie published L'Homme-machine (1747; L’Homme Machine: A Study in the Origins of an Idea, 1960), developing more boldly and completely, and with great originality, his materialistic and atheistic views.

De La Mettrie's book, Man a Machine can be read online here.

After the French Revolution, de La Mettrie's atheistic materialism was no longer considered so shocking in his home country. Pierre Jean Georges Cabanis (1757-1808) was the most ardent proponent of La Mettrie's naturalism. In his Rapports du physique et du moral de l'homme (1802) he wrote that "to have an accurate idea of the operations from which thought results, it is necessary to consider the brain as a special organ designed especially to produce it, as the stomach and the intestines are designed to operate the digestion, (and) the liver to filter bile..."
(English translation, On the Relation Between the Physical and Moral Aspects of Man by Pierre-Jean-George Cabanis, edited by George Mora, translated by Margaret Duggan Saidi from the second edition, reviewed, corrected and enlarged by the author, 1805. The Johns Hopkins University Press, Baltimore and London, 1981, p. 116).

(b) Professor William Lawrence, FRS, is denounced in England for promoting materialism in medicine

It took England much longer than France to accept materialism in medicine: as late as 1819, a prominent surgeon who defended it in print was forced to recant his views. Sir William Lawrence, 1st Baronet FRCS FRS (Cirencester, 16 July 1783 – London, 5 July 1867) was an English surgeon who became President of the Royal College of Surgeons of London and Serjeant Surgeon to the Queen. However, his early professional career was mired in controversy. Forty years before Darwin's Origin of Species was published, Professor Lawrence authored two books in which he espoused the doctrine of materialism. The outcry in the English establishment was so great that he was forced to publicly recant his views. The episode illustrates just how far the scientific establishment was in Professor Lawrence's day from adopting any kind of naturalism, whether metaphysical or methodological. According to his Wikipedia biography:

At the age of 30, in 1813, Lawrence was elected a Fellow of the Royal Society. In 1815 he was appointed Professor of Anatomy and Surgery by the College of Surgeons. His lectures started in 1816, and the set was published the same year.[12] The book was immediately attacked by Abernethy and others for materialism, and for undermining the moral welfare of the people. One of the issues between Lawrence and his critics concerned the origin of thoughts and consciousness. For Lawrence, as for ourselves, mental processes were a function of the brain. Abernethy and others thought differently: they explained thoughts as the product of vital acts of an immaterial kind. Abernethy also published his lectures, which contained his support for John Hunter's vitalism, and his objections to Lawrence's materialism.[13]

In subsequent years Lawrence vigorously contradicted his critics until, in 1819, he published a second book, known by its short title of the Natural history of man.[14] The book caused a storm of disapproval from conservative and clerical quarters for its supposed atheism, and within the medical profession because he advocated a materialist rather than vitalist approach to human life. He was linked by his critics with such other 'revolutionaries' as Thomas Paine and Lord Byron. It was "the first great scientific issue that widely seized the public imagination in Britain, a premonition of the debate over Darwin's theory of evolution by natural selection, exactly forty years later".[15]

Hostility from the established Church of England was guaranteed. "A vicious review in the Tory Quarterly Review execrated his materialist explanation of man and mind";[16][17][18] the Lord Chancellor, in the Court of Chancery (1822), ruled his lectures blasphemous, on the grounds that the book contradicted Holy Scripture (the Bible). This destroyed the book's copyright.[19] Lawrence was also repudiated by his own teacher, Abernethy, with whom he had already had a controversy about John Hunter's teachings. There were supporters, such as Richard Carlile and Thomas Forster, and "The Monthly Magazine", in which Lawrence was compared to Galileo. However, faced with persecution, perhaps prosecution, and certainly ruin through the loss of surgical patients, Lawrence withdrew the book. The time had not yet arrived when a science which dealt with man as a species could be conducted without interference from the religious authorities.

(c) The Materialist Manifesto of 1847

Meanwhile, on the Continent, a revolution was brewing in the biological sciences. Ernst Brucke was one of the revolutionary figures in German physiology during the mid-19th century. In 1845 he banded together with Hermann Helmholtz and Emil du Bois-Reymond to oppose the vitalistic theories of their teacher Johannes Muller. When, in 1847, they were joined by Carl Ludwig, who had not been a student of Muller's, they formed the Berlin Physicalist Society or Berliner Physicalische Gesellschaft. It became popularly known as the "Helmholtz School of Medicine", though its most influential member was not Helmholtz but du Bois-Reymond, who first outlined the group's philosophy in a letter to a friend in 1842:

Brucke and I pledged a solemn oath to put into power this truth: no other forces than the common physical-chemical ones are active within the organism. In those cases which cannot at the time be explained by these forces one has either to find the specific way or form of their Action by means of the physical-mathematical method, or to assume new forces equal in dignity to the chemical-physical forces inherent in matter, reducible to the forces of attraction and repulsion. (Sulloway, F. 1979, Freud: Biologist of the Mind. Basic Books, New York.p.14) (Emphases mine - VJT.)

In the second half of the last century, three giants in the scientific world issued a Manifesto. These were Carl Ludwig (1816—1895), who taught most of the great physiologists of the world active in that age; Emil du-Bois-Reymond (1818—1896), who was the founder of electro-chemistry; and Hermann von Helmholtz (1812—1894), who needs no introduction. This, in substance, is what they agreed upon: "All the activities of living material, including consciousness, are ultimately to be explained in terms of physics and chemistry." (See Chauncey D. Leake, "Perspectives in Adaptation: Historical Background" in Handbook of Physiology, Washington, D.C., American Physiology Society, 1964, section 4, p.5—6.) It is a kind of scientific ideal and still appeals with tremendous force to the modern scientific mind. See Arthur Custance, The Mysterious Matter of Mind. First published in book form in 1980. Available online at http://www.custance.org/old/mind/ as of January 27, 1997.)

The Manifesto of 1847

As Michel Meulders notes in his recent book, Helmholtz: From Enlightenment to Neuroscience (MIT Press, 2010):

As co-actors in the reform of medical studies in Berlin (see chapter 4), Helmholtz, du Bois-Reymond and Brucke wanted to ensure the development of an independent physiology as a sort of organic physics. In association with Carl Frierich Wilhelm Ludwig, a physiologist in Zurich and then in Leipzig, the quartet drew up the Manifesto of 1847, creating an organic physics exclusively based on the laws of physics, chemistry and mathematics, and in which physiology was reduced to its physicochemical fundamentals. The most spectacular outcomes of the manifesto were not only the adoption of a materialist path that henceforth the researchers of the institution would follow openly in the formulation of their scientific method, but also the almost explosive growth of techniques and laboratory equipment conceived for the requirements of their research. (Meulders, 2010, p. 84).

(d) Claude Bernard defines the scientific method in medicine in 1865. Absolute determinism rules in both the organic and inorganic domains of science.

Meanwhile, a scientific revolution was brewing in the field of medicine. The French physician Claude Bernard (1813—1878) has been described as the father of physiology. Claude Bernard's aim, as he stated in his own words, was to establish the use of the scientific method in medicine. In 1865, in his major discourse on scientific method, An Introduction to the Study of Experimental Medicine (1865), Claude Bernard describes what makes a scientific theory good and what makes a scientist important, a true discoverer. He also set forth a credo for physiologists:

In living bodies as in inorganic bodies, laws are immutable and the phenomena governed by these laws are bound to the conditions on which they exist by a necessity and absolute determinism....

A determinism in the conditions of vital phenomena should be one of the axioms of experimenting physicians. If they are thoroughly imbued with the truth of this principle, they will exclude all supernatural intervention from their explanations; they will have unshaken faith in the idea that fixed laws govern biological science...

Determinism thus becomes the foundation of all scientific progress and criticism. (Emphases mine - VJT.)
(Bernard, Claude, An Introduction to the Study of Experimental Medicine (1865), translated by H. C. Greene, New York, Henry Schuman, 1949, p.69.)

5. Biology

Illustration comparing the skeletons of various apes to that of man, from the Frontispiece to Thomas Henry Huxley's Evidence as to Man's Place in Nature (1863). Image courtesy of Benjamin Waterhouse Hawkins (1807-1894) and Wikipedia.

(a) Darwin's theory of evolution. Only explanations in terms of physical laws are genuinely scientific, and scientists should shun recourse to the supernatural until all recourse to natural causes has been exhausted.

Ronald Numbers' 2003 essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, edited by David C. Lindberg and Ronald L. Numbers. Chicago: University Of Chicago Press), describes how the Darwinian principle that any good scientific explanation has to appeal to physical laws soon came to be widely accepted by nineteenth century naturalists, largely because of the prevailing Zeitgeist:

The person most responsible for naturalizing the origin of species — and thereby making the problem a scientific matter — was Lyell's younger friend Charles Darwin (1809-82). As early at 1838 Darwin had concluded that attributing the structure of animals to "the will of the Deity" was "no explanation — it has not the character of a physical law & is therefore utterly useless." Within a couple of decades many other students of natural history (or naturalists, as they were commonly called) had reached the same conclusion. The British zoologist Thomas H. Huxley, one of the most outspoken critics of the supernatural origin of species, came to see references to special creation as representing little more than a "specious mask for our ignorance." (Numbers, 2003, p. 279.)

Numbers candidly acknowledges that the success of Darwinism as a biological theory was largely due to its explicit naturalism, rather than its scientific merits:

In his revolutionary Origin of Species (1859) Darwin aimed primarily "to overthrow the dogma of separate creations" and extend the domain of natural law throughout the organic world. He succeeded spectacularly — not because of his clever theory of natural selection (which few biologists thought sufficient to account for evolution) nor because of the voluminous evidence of organic development that he presented, but because, as one Christian reader bluntly put it, there was "literally nothing deserving the name of Science to put in its place." The American geologist William North Rice (1845-1928), an active Methodist, made much the same point. "The great strength of the Darwinian theory," he wrote in 1867, "lies in its coincidence with the general spirit and tendency of science. It is the aim of science to narrow the domain of the supernatural, by bringing all phenomena within the scope of natural laws and secondary causes."

In reviewing the Origin of Species for the Atlantic Monthly, the Harvard botanist Asa Gray (1810-88) forthrightly addressed the question of how he and his colleagues had come to feel so uncomfortable with a "supernatural" account of speciation. "Sufficient answer," he explained, "may be found in the activity of the human intellect, 'the delirious yet divine desire to know,' stimulated as it has been by its own success in unveiling the laws and processes of inorganic Nature." Minds that had witnessed the dramatic progress of the physical sciences in recent years simply could not "be expected to let the old belief about species pass unquestioned." Besides, he later explained, "the business of science is with the course of Nature, not with interruptions of it, which must rest on their own special evidence." Organic evolution, echoed his friend George Frederick Wright (1838-1921), a geologist and ordained Congregational minister, accorded with

the fundamental principle of science, which states that we are to press known secondary causes as far as they will go in explanation of facts. We are not to resort to an unknown (i.e., supernatural) cause for explanation of phenomena till the power of known causes has been exhausted. If we cease to observe this rule there is an end to all science and all sound sense.(35)

All of the above statements welcoming Darwinism as a legitimate extension of natural law into the biological world came from Christian scientists of impeccable religious standing: Rice, a Methodist; Gray, a Presbyterian; Wright, a Congregationalist. Naturalism appealed to them, and to a host of other Christians, in part because it served as a reliable means of discovering God's laws. (Numbers, 2003, p. 280.)

From an Intelligent Design perspective, this stage of the development of methodological naturalism was particularly disastrous, because it put forward an over-simplified model of what an ideal scientific explanation should look like: for Darwin and many of his contemporaries, a proper scientific explanation of any phenomenon had to account for it in terms of some physical law. What this account leaves out is information. Laws, being very concise statements, are low in information content. Living organisms are distinguished by a high degree of complex specified information, of a prescriptive variety. To try to explain all of this information in terms of some as-yet-undiscovered scientific laws (coupled with initial conditions) that would account for the origin and characteristics of living things is to put science in a straitjacket.

(b) A Power Play in Science. The X-Club.

David Wilcox, in an interesting essay entitled, Evolution as History and the History of Evolution describes the history of the X-Club:

One hundred and fifty years ago, according to Gillespie (1979), most naturalists accepted the idea of common ancestry, but they differed on how new forms arose. The Establishment at Oxford (Buckland, for instance) evidently thought that God occasionally remodeled an existing form into a perfectly adapted new type (Rupke, 1983). The Radical Materialists such as Grant and Knox followed Lamarck in considering matter itself energized with an intrinsic tendency for unifomm development (Desmond, 1989). The followers of German Naturphilosophie (Richard Owen, for instance) held the theory that autonomous extra-material archetypes shaped lineages progressively into their own images (Desmond, 1982). All the schools (with the exception of Louis Agassis) viewed fossil sequences as demonstrations of common descent. They differed on the nature of the power that shaped biological form, but not on whether things shared common ancestry. One further note: although they differed in their philosophies of nature, each school had both Christian and non-Christian adherents.

According to historian James Moore (1982), however, around 1840 a new movement of young middle-class reformers calling themselves "Naturalists" appeared. This group as young adults typically changed their creed from Christianity (which they felt was morally bankrupt) to one based on "Nature." They were "poets and lawyers, doctors and manufacturers, novelists and naturalists, engineers and politicians." The group included such well-known individuals as George Eliot, Herbert Spencer, Matthew Arnold, Francis Galton, J. A. Froude, G. H. Lewes, Charles Bray, Alfred Lord Tennyson, John Tyndall, F. W. Newman, A. H. Clough, Harriet Martineau, F. P. Cobbe, and, of course, T. H. Huxley. Moore shows that the central feature of this new creed was the redefinition of human nature, society, order, law, evil, progress, purpose, authority, and nature itself in terms of the Naturalists' particular view of Nature, as opposed to the Christian Scriptures. In fact, they tended to attack the Christian Scriptures as the true source of societal evil. God, if he existed, was to be known only through the Nature which he made. Thus, according to Moore (1982) and Young (1980), "positivism" was not primarily a methodology for science, but a religious movement that sought to replace the cultural dominance of the Established Church.

Charles Darwin launched his theory of biological change in this context. He proposed a mechanism for the appearance of new forms that did not depend on any pre-existing or exterior shaping forces. The environment became the only needed constraint. It was a theory of strategic importance for the Naturalists, particularly for the "X" club, Huxley's "Young Guard" party in science.

The significance of a mechanism can be understood only within the world views of its proponents. The "Naturalism" that initially proposed and supported Darwin's mechanism was both a world view and a social movement. These individuals viewed the world as autonomous, and the Darwinian mechanism as autonomous creator. The scientific members of this movement, Huxley's "X" club, were engaged in a successful campaign to wrest the university chairs in the sciences from the clergymen/naturalists of the Established Church. The ability of Darwinism to replace the divine with a natural process was a critical support...

The Naturalists succeeded. The "Young Guard" used the trappings of religion to sacralize their "science." Three centuries of cooperation between science and religion were forgotten and their history was rewritten as "warfare." Hymns to nature were sung at popular lectures before the giving of "lay sermons" by a member of Galton's "Scientific Priesthood." Museums were built to resemble cathedrals, and following frantic string-pulling by Lubbock (a member of the "X" club) Charles Darwin was buried in Westminster Abbey. The new church was established (Moore, 1982).

6. Psychology

Four views of how the mental and physical interact: Interactionist Dualism (Descartes), Epiphenomenalism (T. H. Huxley), Psycho-Physical Parallelism (Leibniz) and Non-Reductive Physicalism (Donald Davidson, John Searle). Image courtesy of Wikipedia.

One ingredient was still missing from the naturalism: scientific acceptance of the causal closure of the physical realm. In his Naturalism in The Stanford Encyclopedia of Philosophy, philosopher David Papineau describes the process whereby the discovery of the law of the conservation of energy in the mid-nineteenth century led to the widespread acceptance, by around 1950, of the physicalist principle that any state of affairs that has physical effects must itself be physical:

During the eighteenth-century heyday of Newtonian physics, science raised no objections to non-physical causes of physical effects. As a result, the default philosophical view was a non-naturalist interactive pluralism which recognized a wide range of such non-physical influences, including spontaneous mental influences (or 'determinations of the soul' as they would then have been called).

The nineteenth-century discovery of the conservation of energy continued to allow that sui generis non-physical forces can interact with the physical world, but required that they be governed by strict force laws. This gave rise to an initial wave of naturalist doctrines around the beginning of the twentieth century. Sui generis mental forces were still widely accepted, but an extensive philosophical debate about the significance of the conservation of energy led to a widespread recognition that any such mental forces would need to be law-governed and thus amenable to scientific investigation along with more familiar physical forces.[5]

By the middle of the twentieth century, the acceptance of the casual closure of the physical realm led to even stronger naturalist views. The causal closure thesis implies that any mental and biological causes must themselves be physically constituted, if they are to produce physical effects. It thus gives rise to a particularly strong form of ontological naturalism, namely the physicalist doctrine that any state that has physical effects must itself be physical.

In a footnote, Papineau remarks:

According to the historian F.M. Turner 1974 'the contemporary significance of this law [conservation of energy] was immense and probably more destructive to a supernatural interpretation of nature than was evolution by natural selection'. We would like to thank Dan Wegener for information about this issue.

I would like to point out in passing that scientists who oppose materialism have conscientiously striven to ensure that their models of mind-brain interaction are perfectly compatible with the laws of physics, and to explain why this is so. One notable recent example is the dualist neuroscientist Sir John Eccles (d. 1997), who provided a detailed account of the neurophysiological aspects of free will in Chapter VIII: Man, Freedom, and Creativity of his book, Facing Reality, 1970, pp.118-129. Eccles' views on the relationship between mind and body are critically assessed by David Pratt in his article, John Eccles on Mind and Brain (Sunrise magazine, 1995), and by Donald E.Watson and Bernard O.Williams in their article, Eccles' Model of the Self Controlling Its Brain (NeuroQuantology 2003; 1: 119-128).

7. The relationship between science and religion

A photo of the Difference Engine constructed by the London Science Museum, based on the plans for Charles Babbage's Difference Engine No. 2. Image courtesy of User geni and Wikipedia.

(a) The Bridgewater Treatises (1833-1840)

Francis Henry Egerton, 8th Earl of Bridgewater (11 November 1756 – 11 February 1829), known as Francis Egerton until 1823, was a noted British eccentric, and supporter of natural theology. Upon his death, he left 8000 pounds at the disposal of the president of the Royal Society, to be paid to the author or authors who might be selected to write and publish 1000 copies of a treatise "On the Power, Wisdom and Goodness of God, as manifested in the Creation". Mr Davies Gilbert, who then filled the office, selected eight persons, each to undertake a branch of this subject, and each to receive 1000 pounds as his reward, together with any benefit that might accrue from the sale of his work, according to the will of the testator.

The treatises first appeared during the years 1833 to 1840, and afterwards in Bohn's Scientific Library. The titles of the treatises were as follows:

• The Adaptation of External Nature to the Moral and Intellectual Condition of Man, by Thomas Chalmers, D. D.
  
• On The Adaptation of External Nature to the Physical Condition of Man, by John Kidd, M. D.
  
• Astronomy and General Physics considered with reference to Natural Theology, by William Whewell, D. D.
  
• The hand, its Mechanism and Vital Endowments as evincing Design, by Sir Charles Bell.
  
• Animal and Vegetable Physiology considered with reference to Natural Theology, by Peter Mark Roget.
  
• Geology and Mineralogy considered with reference to Natural Theology, by William Buckland, D.D.
  
• On the History, Habits and Instincts of Animals, by William Kirby.
  
• Chemistry, Meteorology, and the Function of Digestion, considered with reference to Natural Theology, by William Prout, M.D.

Let us stop and ponder the fact that eight notable scientists, from fields as diverse as astronomy, geology and physiology, were willing to publish scientific treatises whose avowed aim was to demonstrate the Power, Wisdom and Goodness of God. And now ask yourself this: could these eminent scientists have published these works, if methodological naturalism had been part-and-parcel of the accepted way of doing science back in the 1830s? Obviously not.

According to the Wikipedia article on Natural theology:

In response to the claim in Whewell's treatise that "We may thus, with the greatest propriety, deny to the mechanical philosophers and mathematicians of recent times any authority with regard to their views of the administration of the universe", Charles Babbage published what he called The Ninth Bridgewater Treatise, A Fragment.[7] As his preface states, this volume was not part of that series, but rather his own reflections on the subject. He draws on his own work on calculating engines to consider God as a divine programmer setting complex laws underlying what we think of as miracles, rather than miraculously producing new species on a Creative whim. There was also a fragmentary supplement to this, posthumously published by Thomas Hill.[8]

The works are of unequal merit; several of them took a high rank in apologetic literature, but they attracted considerable criticism. One notable critic of the Bridgewater Treatises was Edgar Allan Poe, who wrote Criticism.[9] Robert Knox, an Edinburgh surgeon and leading advocate of radical morphology, referred to them as the "Bilgewater Treatises", to mock the "ultra-teleological school". Though memorable, this phrase overemphasises the influence of teleology in the series, at the expense of the idealism of the likes of Kirby and Roget.[10]

(b) Reverend Baden Powell's theological argument that natural laws cannot be broken, because they are promises made by God

One major reason why the principle that the laws of Nature cannot be broken secured widespread acceptance in the nineteenth century, was because of an ingenious theological defense of this claim, by the mathematician and Anglican clergyman, Reverend Baden Powell, whose son, Robert Baden-Powell, founded the Scout Movement in 1907. According to the Wikipedia article on Baden Powell:

Powell was an outspoken advocate of the constant uniformity of the laws of the material world. His views were liberal, and he was sympathetic to evolutionary theory long before Charles Darwin had revealed his ideas. He argued that science should not be placed next to scripture or the two approaches would conflict, and in his own version of Francis Bacon's dictum, contended that the book of God's works was separate from the book of God's word, claiming that moral and physical phenomena were completely independent.[4]

His faith in the uniformity of nature (except man's mind) was set out in a theological argument; if God is a lawgiver, then a "miracle" would break the lawful edicts that had been issued at Creation. Therefore, a belief in miracles would be entirely atheistic.[5] Powell's most significant works defended, in succession, the uniformitarian geology set out by Charles Lyell and the evolutionary ideas in Vestiges of Creation published anonymously by Robert Chambers which applied uniform laws to the history of life in contrast to more respectable ideas such as catastrophism involving a series of divine creations.[4] "He insisted that no tortured interpretation of Genesis would ever suffice; we had to let go of the Days of Creation and base Christianity on the moral laws of the New Testament."[6]

Works
History of Natural Philosophy from the Earliest Periods to the Present Time Published by Longman, Brown, Green, and Longmans, 1837, 396 pages.
The Connexion of Natural and Divine Truth Or the Study of the Inductive Philosophy Considered as Subservient to Theology: Or, The Study of the Inductive Philosophy, Considered as Subservient to Theology, Published by J.W. Parker, 1838, 313 pages.
The Order of Nature: Considered in Reference to the Claims of Revelation : a Third Series of Essays, Published by Longman, Brown, Green, Longmans, & Roberts, 1859, 495 pages.

See also: http://www.human-nature.com/dm/chap1.html

Powell had a very consistent approach to the problem of harmonizing science and theology, as Robert Young explains in Darwin's Metaphor: Nature's Place in Victorian Culture (Cambridge University Press, 1985):

Powell's position throughout his writings was consistent: the only rational and safe solution to the problem of reconciling science and theology is to keep them completely separate and to give up entirely the concept of miracle as having anything to do with science. This was a radical, uncompromising solution to the problems posed for natural theology by science: the physical and moral departments of nature should be divorced once and for all. The Bible was an inspirational document, having nothing to do with science. Any attempt to stretch Scripture to accommodate science would harm both faith and reason. In 1855 he wrote that any solution short of this had always resulted "either in a lamentable antagonism and hostility, or in futile attempts to combine them in incongruous union, upon fallacious principles." The foundations of scientific and religious truth are, he insisted, entirely separate. (1985, pp. 146-147.)

Despite his death in 1860, shortly after the publication of Darwin's Origin of Species, Powell's arguments proved to have a profound influence on the creation-evolution debate, as Young narrates:

In spite of his obscurity in recent secondary literature, Powell was the most clear-sighted of the interpreters of the uniformitarian point of view... I should add that his essays were commonly reviewed with Darwin's Origin of Species, and he was one of the contributors to Essays and Reviews - a work in the naturalist tradition which was causing more controversy in 1860 than Darwin's. (Essays and Reviews went through six editions by 1865.) Darwin also acknowledges Powell's work in the preface to later editions of the Origin. Powell suits us, because he interpreted Lyell in the 1830s in a monograph entitled On the Connection of Natural and Divine Truth, defended [Robert Chambers'] Vestiges in "The Philosophy of Creation," and was an early advocate of Darwin in his "Study of the Evidences of Christianity," his contribution to Essays and Reviews (which evoked a flood of replies). (1985, p. 146.)

Powell's faith in the uniformity of nature was not complete, however: he made a special exception for man's mind. In this respect, he differed from both Robert Chambers (author of The Vestiges) and Charles Darwin. The mind was the fly in Powell's theological ointment: for if the mind is nothing more than the brain, and the behavior of the brain is determined by antecedent physical causes, then the notions of free will and responsibility become extremely difficult to defend.

(c) The Declaration of Students of the Natural and Physical Sciences, issued in London in 1864

Left: Sir James Prescott Joule. Illustration in Popular Science Monthly, Volume 5, 1874. Image courtesy of Wikipedia.
Right: Adam Sedgwick. From a photo taken by William Farren in 1867. Image courtesy of Wikipedia.

Source: http://books.google.co.jp/books?id=qwaRUNj6S34C&pg=PA32&lpg=PA32&dq=Capel+Henry+Berger&source=bl&ots=AvoLJjaNXy&sig=cpFsvOdcQL-dEF-fF1Fa3O2q1e0&hl=en&sa=X&ei=5eWWT6WlO-nKmQXpy-H5DQ&redir_esc=y#v=onepage&q=Capel%20Henry%20Berger&f=false

Religion and the Challenges of Science by William Sweet, Richard Feist

http://www.bris.ac.uk/philosophy/current/undergrad/pastunits/units0506/kant.html Kant

Naturalism (Behe) http://www.discovery.org/f/697

http://www.evolutionnews.org/2012/04/judge_jones_sai058871.html

On Saturday, 16 April 1864, a group of young London chemists, led by a young chemist named Herbert McLeod (1841-1923) and calling themselves 'Students of the natural and physical sciences', put together a statement expressing their belief that "it is impossible for the Word of God, as written in the book of nature, and God's Word written in Holy Scripture, to contradict one another, however much they may appear to differ," and expressing their confident belief that "a time will come when the two records will be seen to agree in every particular." A student of science who "finds that some of his results appear to be in contradiction to the Written Word, or rather to his own interpretations of it," should not "presumptously affirm that his own conclusions must be right, and the statements of Scripture wrong," but rather, "leave the two side by side till it shall please God to allow us to see the manner in which they may be reconciled."

After a slight revision, the statement, retitled a Declaration of Students of the Natural and Physical Sciences, was circulated with the aim of obtaining the signatures of as many scientists as possible. Initially, most of the signatories were young men from the Royal College of Chemistry. Over the next few months, the chemists who drafted the Declaration managed to muster no less than 717 signatures, mostly from scientists, including 86 signatures from Fellows of the Royal Society. At that time the Royal Society had 673 members, and there were 6,480 members of various scientific societies of London. The Declaration was published in the middle of May 1865.

Some prominent scientists signed the Declaration, including James Joule and Adam Sedgwick. A few, like Michael Faraday, felt unable to sign the Declaration because they "did not think the clergy had any right to interfere in the matter [of science]," but nonetheless supported it. Some scientists agreed with the broad thrust of the Declaration but disagreed with the wording on minor points. Still others, including Sir John Herschel, opposed it the Declaration as divisive. Herschel wrote a letter to the Athenaeum (later reprinted in The Times), stating that he found the Declaration "an infringement of that social forbearance which regards the freedom of religious opinion in this country with especial sanctity" that he be called upon publicly to avow or disavow "in writing, any doctrine or statement , however carefully or cautiously drawn up."

The Declaration attracted several outspoken critics from the outset, including Professor John Percy, who wrote an anonymous letter to The Times, calling the Declaration a "vague confession of faith" and accusing McLeod of "officious meddling." Percy, who believed that there were many different kinds of truth, wished to protect the domain of science from encroachments by ecclesiastical authority, urging, "let men of science mind their own business, and theologians theirs" - a sentiment that many scientists in his day would have echoed.

However, the most prominent critic of the Declaration was the British mathematician Augustus De Morgan. In his work, A Budget of Paradoxes, Section O, he attacked the document as a scientific Shibboleth, and argued that scientists should not be called on to approve or disapprove, in writing, any religious doctrine or statement. In opposition to the Declaration, De Morgan then put forward an alternative declaration, "which was proposed in the Athenaeum, as worthy to be signed both by students of theology, and by students of science, especially in past time." The original and De Morgan's proposed alternative are both tabled below.

What is remarkable, historically speaking, is that both documents fall afoul of what scientists now refer to as methodological naturalism. Even the alternative version put forward by de Morgan expressed a belief in the "Word of God, as correctly read in the Book of Nature," as well as expressing "faith as to our future state."

(d) The relationship between science and religion turns nasty. Methodological naturalism is invoked to drive out the supernatural (1874)

In his 2003 essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, edited by D. C. Lindberg and R. L. Numbers, Chicago: University Of Chicago Press), Ronald Numbers notes that "the adoption of naturalistic methods did not drive most nineteenth-century scientists into the arms of agnosticism or atheism": it simply altered the way in which they envisaged God as interacting with the world. Species could still be seen as as the products of divinely ordained natural laws, and many scientists who espoused these views remained churchgoing Christians. So what went wrong? According to Numbers, the trouble began when science began declaring itself to be the only legitimate way of knowing anything:

The relatively smooth passage of naturalism turned nasty during the last third of the nineteenth century, when a noisy group of British scientists and philosophers, led by Huxley and the Irish physicist John Tyndall (1820-93), began insisting that empirical, naturalistic science provided the only reliable knowledge of nature, humans, and society...

For centuries men of science had typically gone out of their way to assure the religious of their peaceful intentions. In 1874, however, during his presidential address to the British Association for the Advancement of Science, Tyndall declared war on theology in the name of science. Men of science, he threatened, would

wrest from theology, the entire domain of cosmological theory. All schemes and systems which thus infringe upon the domain of science must, in so far as they do this submit to its control, and relinquish all thought of controlling it. Acting otherwise proved always disastrous in the past, and it is simply fatuous today.

The war between science and religion had begun.

D. Exposing the Hoary History of Methodological Naturalism: Does it really go back to the Middle Ages?

Portrait of Nicolas Oresme, a renowned medieval bishop, mathematician, scientist, philosopher and economist, who is often falsely portrayed as a 14th century advocate of methodological naturalism by opponents of Intelligent Design. Miniature from Nicole Oresme's Traite de l’espere, Bibliotheque Nationale, Paris, France, fonds francais 565, fol. 1r. Image courtesy of Wikipedia.

1. Was Methodological Naturalism already an accepted principle of science in the Middle Ages?

(a) Arguments in support of the view that Jean Buridan and Nicolas Oresme espoused Methodological Naturalism

Ronald Numbers, who is widely regarded as one of the leading experts on the history of creationism, argues that while the term "methodological naturalism" may be of recent origin, the principle underlying it goes back much further. He writes:

The phrase "methodological naturalism" seems to have been coined by the philosopher Paul de Vries, then at Wheaton College, who introduced it at a conference in 1983 in a paper subsequently published as "Naturalism in the Natural Sciences," Christian Scholar's Review, 15(1986), 388-396. De Vries distinguished between what he called "methodological naturalism," a disciplinary method that says nothing about God's existence, and "metaphysical naturalism," which "denies the existence of a transcendent God."
(p. 320 of: Ronald L. Numbers, 2003. "Science without God: Natural Laws and Christian Beliefs." In When Science and Christianity Meet, edited by David C. Lindberg, Ronald L. Numbers. Chicago: University Of Chicago Press, pp. 265-285.)

However, Numbers contends that methodological naturalism was recognized as a principle of science as far back as the Middle Ages. The principle invoked a distinction between primary causes (i.e. God, the Creator) and secondary causes (i.e. natural agents).

By the late Middle Ages the search for natural causes had come to typify the work of Christian natural philosophers. Although characteristically leaving the door open for the possibility of direct divine intervention, they frequently expressed contempt for soft-minded contemporaries who invoked miracles rather than searching for natural explanations. The University of Paris cleric Jean Buridan (ca. 1295-ca. 1358), described as "perhaps the most brilliant arts master of the Middle Ages," contrasted the philosopher's search for "appropriate natural causes" with the common folk's erroneous habit of attributing unusual astronomical phenomena to the supernatural. (Numbers, 2003, p. 267)

John Farrell, in an online post entitled, A Problem of Credibility (Thursday, September 13, 2007), argues that Buridan was a methodological naturalist:

Jean Buridan, the cleric and philosopher of the mid 1300s whose influence on medieval science and philosophy was, for quite some time, more widespread in Europe than that of Aquinas or Albert the Great, wrote in his Quaestiones super quattuor libris de caelo et mundo, "In natural philosophy one should consider processes and causal relationships as if they always came about in some natural fashion; therefore, God is no less the cause of this world and of its order, than if this world were eternal." [emphasis mine]

That sure sounds like methodological naturalism to me. It's also common sense.

Nicole Oresme

Nicole Oresme is also commonly cited as an example of a medieval natural philosopher who endorsed methodological naturalism. To quote Ronald Numbers again:

In the fourteenth century the natural philosopher Nicole Oresme (ca. 1320-82), who went on to become a Roman Catholic bishop, admonished that, in discussing various marvels of nature, "there is no reason to take recourse to the heavens, the last refuge of the weak, or demons, or to our glorious God as if He would produce these effects directly, more so than those effects whose causes we belive are well known to us." (Numbers, 2003, p. 267.)

Professor Edward Grant, in his work, God and Reason in the Middle Ages (Cambridge University Press, 2001), goes even further and attempts to portray Nicole Oresme as a methodological naturalist:

He always sought natural explanations (as these quotations show) and refused to invoke supernatural or unnatural explanations, such as God, or magic, or demons. Although Oresme seems to have believed that understanding the articles of faith, he never let his faith intrude into his natural philosophy. (Grant, 2001, pp. 202-203.)

Were Buridan and Oresme methodological naturalists?

If Ronald Numbers is going to quote from Buridan and Oresme, then he really should cite them in their appropriate context.

(a) Jean Buridan was no methodological naturalist

Numbers asserts that the cleric Jean Buridan (ca. 1295-ca. 1358), "contrasted the philosopher's search for 'appropriate natural causes' with the common folk's erroneous habit of attributing unusual astronomical phenomena to the supernatural." Here's what Buridan actually said in his Questions on Aristotle's Meteorology:

There are several ways of understanding the word natural. The first [is] when we oppose it to supernatural (and the supernatural effect is what we call a miracle). And it is clear that the meteorological effects are natural effects, insofar as they are produced naturally, and not miraculously... The philosophers, consequently, explain them by the appropriate natural causes; but common folk, not knowing of causes, believe that these phenomena are produced by a miracle of God, which is usually not true... [Emphasis mine - VJT.] Source: Nicole Oresme and the Marvels of Nature: A Study of his "De causis mirabilium" with Critical Edition, Translation and Commentary by Bert Hansen (Toronto: Pontifical Institute of Medieval Studies, 1985), p. 59.

Note the qualification: "which is usually not true." And note also that Buridan is talking about meteorology, not biology.

Now, it is certainly true that while Buridan, as a devout Christian, allowed that God could intervene in the natural order of events, he also insisted that "in natural philosophy, we ought to accept actions and dependencies as if they always proceed in a natural way" (Questions on De caelo, book 2, question 9, p. 164 (Moody edition).

I'm afraid I have to disagree with Farrell here. If we look at the claims in Part A above, all that Buridan is asserting here is principle (e), that scientists should avoid appealing to miracles, when attempting to account for empirical phenomena; or equivalently, principle (f), the claim that scientists should confine themselves to natural causes, when attempting to account for observed phenomena. This claim still falls short of methodological naturalism, since: (i) it says nothing regarding the competence of science to explain the entire gamut of physical phenomena; and (ii) all it eliminates is scientific appeals to the supernatural, leaving it still open to a supernaturalist to maintain that observed phenomena also require a deeper, metaphysical explanation.

Commenting on a passage in Aristotle's On Generation and Corruption (2.10.336b25-35; Oxford trans.) in which he declares that .... Buridan writes that "Aristotle wishes to declare here and in the second book of De Generatione how such an order is reasonably from God and how all existing things from God, both celestial and inferior, are harmonious with tregard to the order that is to be perpetually conserved." (Questions on De Caelo, bk. 2, qu. 10, pp. 171-172).

In saying this, he was typical of many late medieval natural philosophers, according to Edward Grant, author of God and reason in the Middle Ages (Cambridge University Press, 2001), some of which can be viewed online at this address . What relevance does this have for intelligent design? Very little, in my opinion. Does it make Buridan a methodological naturalist? Not as the term is understood today. Here's why.

As I see it, the aim of Intelligent Design is to make a persuasive scientific case that certain patterns in Nature can be reliably identified as manifestations of intelligence. Accepting that claim does not commit one to a belief in the supernatural.

Even for ID proponents who believe that God is the author of the intelligently designed patterns we observe in the biological realm, it does not follow that the creation of these designs was a supernatural act. As far as ID is concerned, scientists are welcome to search for pathways leading from simple forms to specified complexity. An ID proponent could, for instance, believe (if he/she wished) that the initial conditions of the primordial Earth were very finely tuned by God, in such a way as to make the emergence of life by natural processes inevitable. Ditto for irreducibly complex systems. So much for the notion that ID is supernaturalistic.

Grant: http://books.google.co.jp/books?id=Dc1IdnM-4A8C&pg=PA102&lpg=PA102&dq=%22for+if+perchance+we+should+have+any+opinion+of+our+own,+this+would+be+proffered+by+us+(God+willing)+in+theological+works+rather+than+in+those+on+physics%22&source=bl&ots=oyyeAXCgwo&sig=fQ9ArouX6C3pzLRZFz0AnY1FUpU&hl=en&sa=X&ei=7hqQT-XcM42yiQfQi8mpBA&redir_esc=y#v=onepage&q=%22for%20if%20perchance%20we%20should%20have%20any%20opinion%20of%20our%20own%2C%20this%20would%20be%20proffered%20by%20us%20(God%20willing)%20in%20theological%20works%20rather%20than%20in%20those%20on%20physics%22&f=false

Grant: http://books.google.co.jp/books?id=UB0Tao4oikEC&pg=PA199&lpg=PA199&dq=Oresme+there+is+no+reason+to+take+recourse+to+the+heavens,+the+last+refuge+of+the+weak,+or+demons&source=bl&ots=u7xSpb74F2&sig=H5hiz5_f15q1N_D7argXcedHep0&hl=en&ei=zlI_S4CGOYHo7AOs3KzIBQ&sa=X&oi=book_result&ct=result&redir_esc=y#v=onepage&q&f=false

(b) Bishop Nicole Oresme wasn't a methodological naturalist, either

In his 2003 essay, Numbers also writes:

In the fourteenth century the natural philosopher Nicole Oresme (ca. 1320-82), who went on to become a Roman Catholic bishop, admonished that, in discussing various marvels of nature, "there is no reason to take recourse to the heavens, the last refuge of the weak, or demons, or to our glorious God as if He would produce these effects directly, more so than those effects whose causes we believe are well known to us."

Here's what Oresme actually said in the Prologue to his treatise, On the Causes of Marvels (De causis mirabilium), also known as the Quodlibeta, composed around 1370:

In order to set people's minds at rest to some extent I propose here, although it goes beyond what was intended, to show the causes of some effects which seem to be marvels and to show that these effects occur naturally, as do the others at which we commonly do not marvel. There is no reason to take recourse to the heavens, the last refuge of the weak, or demons, or to our glorious God as if He would produce these effects directly, more so than those effects whose causes we believe are well known to us. (Emphases mine - VJT.) (Source: Oresme, ibid., p. 137.)

Note the heavily qualified language used in the above passage. Oresme is simply invoking what we now know as Occam's razor. He is arguing that we should not invoke supernatural explanations when natural ones will do the job. This is equivalent to principle (d) which I discussed in Part A above. Such a claim in no way implies methodological naturalism, for it does not tell us whether science will ever be able to explain all observed phenomena, and it does not exclude the supernatural from the domain of science.

Here, Grant is claiming that for Oresme, supernatural explanations lay outside the domain of science. This is ambiguous. Does "supernatural explanations" simply refer to miracles, or does it to any explanation which posits a supernatural agent at the end of a causal chain - e.g. God as an Unmoved Mover?

If by "supernatural explanations" Grant simply means miracles, then all he is claiming is principle (e) in Part A abovem which states that scientists should avoid appealing to miracles, when attempting to account for empirical phenomena. But as we saw, that an observed phenomenon is not miraculous does indeed entail that it is explicable in naturalistic terms, but that does not guarantee that it is explicable in purely naturalistic terms. It might still require God as an ultimate explanatory cause. If it does, then science cannot exclude talk of the supernatural after all.

Much has been made of Oresme's reluctance to invoke miracles in natural philosophy. However, what is often overlooked is that for Oresme and his contemporaries, singular occurrences fell outside the domain of science, which was properly speaking about classes of events. As Loraine Daston explains in her article, Marvelous Facts and Miraculous Evidence in Early Modern Europe (Critical Inquiry, Vol. 18, No. 1, Autumn, 1991, pp. 93-124), this was because Aristotle Oresme excluded from the domain of science not only supernatural phenomena but also preternatural phenomena (rare and marvelous events, such as prodigies, which occur in a natural fashion):

As we have seen, preternatural phenomena, even when free of many portentous associations, had been in principle excluded from scholastic natural philosophy: scientia, properly speaking, was the corpus of demonstrated, universal truths, and preternatural phenomena were by definition exceptions to "that which is always or of that which is for the most part." Neither Aristotle nor his medieval followers denied the existence of such oddities, but they did deny that anomalies resulting from chance and variability could form the subject matter of true science, for "there can be no demonstrative knowledge of the fortuitous." Nicole Oresme's De causis mirabilium (ca. 1370) shows how it was possible for Scholastic philosophers to simultaneously maintain that individual prodigies were wholly natural but nonetheless not susceptible to scientific explanation: "Therefore these things are not known point by point, except by God alone, who knows unlimited things. And why does a black hair appear on the head right next to a white one? Who can know so small a difference in cause?" Well into the seventeenth century, natural philosophy continued to restrict its investigations to common experience. (1991, p. 109.)

What this means is that Oresme, like other Aristotelian philosophers in his day, accepted what I referred to as principle (c) in Part A above - i.e. the claim that science is limited to the study of regularly occurring phenomena. But as we saw above, a scientist can accept this principle without committing him/herself to methodological naturalism. The reason why principle (c) fails to qualify as a genuinely naturalistic principle is that it only deals with the subject matter of science, which is defined as all regular or replicable natural phenomena. To rule out appeals to the supernatural, we need to limit not only the subject matter, but also the kinds of explanations that can be legitimately invoked in order to account for it. Aristotelian science was by definition supernaturalistic, as it required an incorporeal Unmoved Mover to account for any movements occurring in the cosmos.

The point I want to make here is that if this was Oresme's framework for doing science, then his exclusion of miracles should occasion no surprise whatsoever. Since he is endeavoring to explain whole classes of phenomena, then it is perfectly obvious he will not be interested in invoking singular occurrences (such as "acts of God") in order to account for them. However, Oresme's scientific methodology is scientifically limiting: it is by definition incapable of accounting for singular "origin" events occurring in the past, such as the origin of the first living cell.

Alternatively, if by "supernatural explanations" in the passage above, Grant means any reference to supernatural causes, as either ultimate or proximate explanations, then (on this construal) Oresme would be making a claim equivalent to principle (f) in Part A above - i.e. the claim that scientists should confine themselves to natural causes, when attempting to account for empirical phenomena. As I argued, even this claim is not equivalent to methodological naturalism, since: (i) it says nothing regarding the competence of science to explain the entire gamut of physical phenomena; and (ii) all it eliminates is scientific appeals to the supernatural, leaving it still open to a supernaturalist to maintain that observed phenomena also require a deeper, metaphysical explanation which goes beyond the phenomena themselves, to some underlying non-physical Cause. Methodological naturalism, as we argued above, goes further, it asserts that science is capable of fully explaining phenomena as such. Only then can the domain of science be guaranteed full autonomy, as an intellectual mode of inquiry. As I wrote above: "If the empirical phenomena which science deals with cannot be fully explained within a scientific framework, but also require a theistic metaphysical framework in order to fully explain them, then the domain of science can no longer be isolated from that of theology, and science is no longer self-contained as a mode of inquiry."

In any case, it is quite certain that Nicole Oresme, whose cosmology was substantially Aristotelian, firmly believed that science required God as an ultimate explanatory cause, for his system of celestial spheres still needed an Unmoved Mover. Interestingly, the illuminator of Nicole Oresme's Le livre du Ciel et du Monde, a translation of and commentary on Aristotle's De caelo, produced for Oresme's patron, King Charles V, drew the celestial spheres in the conventional order, with the Moon closest to the Earth and the stars highest, but the spheres were concave upwards, centered on God, rather than concave downwards, centered on the Earth. Below this figure, Oresme quotes the Psalms that "The heavens declare the Glory of God and the firmament showeth his handiwork." There is a popular saying that a picture is worth a thousand words, so I'd like to reproduce this picture below.

Illustration of the Celestial spheres, from Le livre du Ciel et du Monde, by Nicole Oresme. Paris, Bibliotheque Nationale de France, Manuscrits, Fr. 565, fo 69 (detail). Image courtesy of Wikipedia.

Finally, Professor Edward Grant, in a biographical essay on Nicolas Oresme in A Companion to Philosophy in the Middle Ages edited by Jorge J. E. Gracia, Timothy B. Noone (Wiley-Blackwell, 2005) acknowledges in passing that Orseme accepted the reality of Biblical miracles, including the miracle of Joshua's long day, even as he argued in his scientific writings that this miracle could not be invoked to settle the question of whether the heavens revolved around the earth or whether the earth rotated daily on its axis:

To the Biblical argument that God aided the army of Joshua by making the sun stand still over Gibeon (Joshua 10:12-14), thus demonstrating that the heavens rotate and the earth is at rest, Orseme suggests that God could have also performed his miracle by temporarily halting the earth's rotation. Both Galileo and Kepler presented explanations of the Joshua miracle, with Kepler's argument resembling Oresme's. ("Nicolas Oresme" by Edward Grant. In Gracis and Noone, 2005, p. 477.)

Oresme on miracles: http://www2.selu.edu/Academics/Faculty/jbell/daston.pdf , http://www.persee.fr/web/revues/home/prescript/article/rhs_0151-4105_1988_num_41_3_4102_t1_0401_0000_3 , Grant.

(c) What would Buridan and Oresme have made of Intelligent Design?

Nevertheless, the reader still want to ask: what would Buridan and Oresme have made of Intelligent Design? That's a fair question. Four points need to be borne in mind here.

1. At the time when Buridan and Oresme lived, Aristotle was the dominant intellectual influence. Aristotle held that the world was eternal, and that each species had always existed. Within his intellectual framework, the problem of how specified complexity arose - let alone how life originally arose - simply did not exist. Nothing arose, except individuals.

2. During the Middle Ages, abiogenesis (more accurately spontaneous generation) was widely believed to be a commonplace and everyday occurrence, as this Wikipedia article illustrates. Indeed, it was even believed that whole animals (e.g. crocodiles) could be generated from inanimate matter such as mud. In keeping with Aristotle's biology, it was also believed that the higher animals, which were naturally "generated from seed" and which were known as "perfect animals" due to their greater complexity, could not be generated from non-living matter.

3. Describing actions as if they "always proceed in a natural way" does not imply that they always proceed in an unintelligent way. "Natural" does not equate to "blind."

4. As Grant points out (op. cit., p. 198), Buridan, as a natural philosopher, was concerned with what he called the "common course of nature" - i.e. regular events and not singular events. Scientists now consider the origin of life on Earth to have been a singular event, yet they continue to investigate this occurrence, as they should. In so doing, they have already moved beyond Buridan's characterization of science as dealing only with regular occurrences.

I would argue that it is intellectually stultifying to limit science to the search for unintelligent explanations of natural phenomena. The world is a more interesting place than it was thought to be in the fourteenth century - or the nineteenth, for that matter. In the twenty-first century, scientists should not be shackled by invocations of dead philosophers. Rather, they should be free to boldly search for the best explanation of natural phenomena, and follow that search wherever it takes them - even if the best explanation turns out to be some kind of intelligent agency.

2. Supernaturalism in the most popular astronomical textbook of the Middle Ages: John of Sacrobosco's On the Sphere of the World

Figure of the heavenly bodies - an illuminated illustration of the Ptolemaic geocentric conception of the Universe by Portuguese cosmographer and cartographer Bartolomeu Velho (d. 1568). Bibliotheque Nationale, Paris. Ptolemy's geocentric model was popularized in John of Sacrobosco's popular medieval astronomy text, On the Sphere of the World (c. 1230). Image courtesy of Wikipedia.

Readers might be surprised to know that the notion of the clockwork universe is not a product of the mechanistic science of the 17th century, but actually goes back to medieval times. The idea can be found in John of Sacrobosco's early 13th-century introduction to astronomy, On the Sphere of the World (c. 1230), which was widely popular in the Middle Ages. Indeed, it was one of the most influential works of pre-Copernican astronomy in Europe, as it was required reading for students at all Western European universities for the next four centuries after it was published.

In his book, Sacrobosco spoke of the universe as the machina mundi, or machine of the world - an image which might appear to leave no place for the supernatural. However, if one reads the book, it becomes readily apparent that Sacrobosco regarded the universe as having been made in the likeness of an Archetype, or Idea in the Mind of God, Who disposed it to behave in a regular fashion. At the end of his book, Sacrobosco also suggested that the reported eclipse of the Sun at the crucifixion of Jesus Christ was a disturbance in the order of the machine of the world. Hence it could only have been a miracle.

The following extracts from Sacrobosco's book illustrate the supernaturalism which pervades his work:

CHAPTER ONE

THE FOUR ELEMENTS. The machine of the universe is divided into two, the ethereal and the elementary region. The elementary region, existing subject to continual alteration, is divided into four For there is earth, placed, as it were, as the center in the middle of all, about which is water, about water air, about air fire, which is pure and not turbid there and reaches to the sphere of the moon, as Aristotle says in his book of Meteorology. For so God, the glorious and sublime, disposed....

THE HEAVENS SPHERICAL. There are three reasons why the sky is round: likeness, convenience, and necessity. Likeness, because the sensible world is made in the likeness of the archetype, in which there is neither end nor beginning; wherefore, in likeness to it the sensible world has a round shape, in which beginning or end cannot be distinguished. Convenience, because of all isoperimetric bodies the sphere is the largest and of all shapes the round is most capacious. Since largest and round, therefore the most capacious. Wherefore, since the world is all-containing, this shape was useful and convenient for it. Necessity, because if the world were of other form than round -- say, trilateral, quadrilateral, or many-sided -- it would follow that some space would be vacant and some body without a place, both of which are false, as is clear in the case of angles projecting and revolved....

CHAPTER TWO - OF THE CIRCLES AND THEIR NAMES

THE TWO MOVEMENTS AGAIN. Be it understood that the "first movement" means the movement of the primum mobile, that is, of the ninth sphere or last heaven, which movement is from east through west back to east again, which also is called "rational motion" from resemblance to the rational motion in the microcosm, that is, in man, when thought goes from the Creator through creatures to the Creator and there rests.

The second movement is of the firmament and planets contrary to this, from west through east back to west again, which movement is called "irrational" or "sensual" from resemblance to the movement of the microcosm from things corruptible to the Creator and back again to things corruptible....

CHAPTER FOUR

ECLIPSE DURING THE PASSION MIRACULOUS. From the aforesaid it is also evident that, when the sun was eclipsed during the Passion and the same Passion occurred at full moon, that eclipse was not natural -- nay, it was miraculous and contrary to nature, since a solar eclipse ought to occur at new moon or thereabouts. On which account Dionysius the Areopagite is reported to have said during the same Passion, "Either the God of nature suffers, or the mechanism of the universe is dissolved."

If the author of the most popular astronomy text of the Middle Ages felt free to refer to God in this fashion, then I think we may safely reject the idea that medieval scientists espoused any kind of methodological naturalism.

3. Was St. Albert the Great a methodological naturalist?

Image of St. Albert the Great (d. 1280) from a fresco of 1352 (in Treviso, Italy) by Tommaso da Modena (1326-1379). Courtesy of Wikipedia.

St. Albert the Great was a Dominican friar, a Catholic bishop and a Doctor of the Church, who was called "Magnus" ("the Great") during his own lifetime, due to his reputation as a scholar and philosopher. He was also an immensely learned scientist and polymath, whose knowledge was unrivaled in his day.

Professor Edward Grant, in his work, God and Reason in the Middle Ages (Cambridge University Press, 2001), portrays St. Albert the Great as a theologian who strove to keep science and theology separate. Although he does not refer to St. Albert as a methodological naturalist, Grant nevertheless asserts that St. Albert (and his pupil, St. Thomas Aquinas) "both chose to keep the theologization of natural philosophy to a minimum" and that St. Albert's "basic conviction" was that "unless unavoidable, theology should not intrude into natural philosophy" (2001, p. 192). However, if we look beyond Grant's interpretive lens to the actual passages he cites from St. Albert's writings, a quite different portrait emerges.

Let us consider the first piece of evidence put forward by Grant: a quotation from St. Albert on the science of physics, which he chooses to define as Aristotelian (Peripatetic) philosophers have done, without recourse to theology:

Pursuing what we have in mind, we must take what we term 'physics' more as what accords with the opinion of Peripatetics than as anything we might wish to introduce from our knowledge ... for if perchance we should have any opinion of our own, this would be proffered by us (God willing) in theological works rather than in those on physics. (Cited in Grant, 2001, p. 192.)

Grant draws the following moral:

Albertus thus believed that Aristotle's natural philosophy was to be treated naturally, in the customary manner of Peripatetics. Where theological issues might be involved, they were to be treated in theological treatises. (2001, p. 192)

Grant is conflating two claims here - neither of which is equivalent to methodological naturalism. First, he declares that "Aristotle's natural philosophy was to be treated naturally," without telling us what that means. If it means (as Aristotle contended) that the proper subject matter of physics is natural bodies, then a supernaturalist could readily agree. As we saw in Part A above, this is simply equivalent to principle (b), which that defines science as the systematic study of physical phenomena. Such a claim poses no threat to supernaturalism, as it does not assert that science is comptent to explain physical phenomena solely in terms of other physical phenomena, making the supernatural redundant. In any case, as we shall see below in our discussion of Aquinas, Aristotle's physics was anything but naturalistic: it invoked an incorporeal Unmoved Mover to explain natural changes occurring in the heavens and on earth.

Second, Grant contends that for St. Albert, "theological issues" don't belong in a book on natural philosophy but in a theological treatise. Grant is being vague here. If by "theological issues" he means matters of Divinely revealed faith (e.g. speculation about whether Jesus Christ violated the laws of physics when He fed the 5,000, or whether He accomplished the miracle in a less "disruptive" manner), then even a supernaturalist would agree that discussion of such issues does not belong in a physics text. But if by "theological issues" he means the existence of an Intelligent, Incorporeal Mover of the cosmos, then that is an issue that is certainly germane to physics. The question of whether change occurring in the cosmos can be explained without reference to a supernatural Being is a vital one, no matter what you happen to believe. And for Aristotle, the answer was a firm "No," as he makes clear in Book VIII of his Physics, where he reasons that there must be an incorporeal Unmoved Mover. In that sense, Aristotle was a supernaturalist.

A second piece of evidence cited by Grant is a passage in St. Albert's Commentary on De caelo, where he discusses whether the heaven is ungenerable or incorruptible, then mentions that Jews, Christians and Muslims believe that it was created ex nihilo, and finally decides not to discuss this opinion in his commentary: "But with regard to this opinion, it is not relevant for us to treat it here." (Book 1, tr. 1, ch. 8, col. 2-20, col. 1.) He then opts to discusses the opinion that "the heaven is generated from something preexisting," even though it runs contrary to faith.

What Grant neglects to mention here is that in St. Albert the Great's day, there was not a scintilla of scientific evidence that the world had a beginning. For St. Albert, the question of whether God could have made the world 6,000 years ago out of nothing, as he devoutly believed, would have had no place in a physics text of his day, since physics, insofar as it treats of God, deals not with what God can do in the abstract, but only with what He can be shown to have done, by the natural light of reason, as opposed to Divinely revealed faith. That, I would suggest, is the distinction that St. Albert draws. What he is saying here is quite different from the claim made by methodological naturalists, that God-talk has no place in science. Rather, St. Albert is asserting that we have no right to speculate about God's powers in a physics text. We have to stick to the data provided by Nature.

A third item of evidence listed by Grant is taken from his Commentary on De caelo, where he treats of the vexed question of "whether there is one world or more." In this passage, St. Albert concludes, on the basis of his understanding of Aristotelian physics, that "it is impossible that there be several worlds, or that more can be made." He anticipates that some of his readers will rise the theological objection that "God could have made more worlds if He wished," and he replies that "Here our understanding is about what is impossible and necessary with respect to the essential and proximate causes of the world." St. Albert then continues: "And there is a great difference between what God can do by His absolute power and what can be done in nature [or by nature]."

This passage readily lends itself to the interpretation I suggested above, which states that it is not the business of physics to discuss what God can do in the abstract, but only with what He can be shown to have done, by the natural light of reason, as opposed to Divinely revealed faith. In other words, St. Albert is simply saying that we have no right to speculate about God's powers in a physics text. We have to stick to the data provided by Nature.

A fourth category of evidence to which Grant attaches great weight concerns St. Albert's infrequent references to God in his scientific writings:

Albertus kept theological references in his natural philosophy to a minimum, as is evident in his Aristotelian commentaries. In the 261 chapters that comprise the 8 books in his Commentary on the Physics, Albertus (deus and its variants) in 24, or in approximately 9 per cent of his chapters, and in the 111 chapters that make up the four books of his Commentary on De caelo, he mentions God in 9, or approximately 8 per cent of the total. Most of Albertus's uses of the term God in his Commentary on the Physics are in direct response to Aristotle's text, especially in the eighth book. Thus, of the 64 occurrences of primus motor, that is, first mover or God, 55 occur in book 8; of the 69 occurrences of causa prima, that is, first cause, or God, 37 occur in book 8; and of the 78 occurrences of deus, God, 40 occur in the eighth book.

Most of these occurrences are in direct response to Aristotle's own mentions of God, or gods, or something about divinity. They have nothing to do with considerations of faith or theology.

In reply: first of all, it makes absolutely no difference whether St. Albert the Great referred to God 64 times, or 37, or 78, in his writings on physics. A single reference would be enough. That would suffice to show that St. Albert didn't believe that God-talk has no place in science, as methodological naturalists contend. While Grant does not make the mistake of identifying St. Albert the Great as a methodological naturalist, he endeavors to show that St. Albert tried to keep God-talk to a minimum when doing science. But that claim just won't wash. Either God-talk has a legitimate place in science or it does not. If it does, then it is perfectly proper to invoke God as a scientific explanation of phenomena, and as the ultimate explanation of all natural phenomena, God's role can hardly be minimized. Surely St. Albert must have appreciated this point.

Second, Grant provides no evidence that it was ever St. Albert's intention to keep "theological references in his natural philosophy to a minimum," nor does he even bother to define the term "theological references." Does he mean references to dogmas of the Catholic faith (which, as we have seen, St. Albert did not want to see included in physics texts), or does he simply mean references to God (Whose existence St. Albert held to be knowable by natural reason alone, unlike the dogmas of faith)?

Third, Grant's assertion, that St. Albert the Great mentioned God in only 9 per cent of the chapters in his Commentary on the Physics, is worthless, in the absence of a comparison with: (a) other scientists of his day, whose references may have been even fewer for all we know; and (b) scientists from other periods - e.g. the seventeenth, eighteenth and nineteenth centuries. How often did they mention God in their physics texts? Grant doesn't tell us.

Grant's fifth and final item of evidence that St. Albert endeavored to minimize references to God in natural philosophy is that he fails to mention God in many passages where, as a theologian, he might have been expected to. For instance, in his lengthy commentary on the infinite, St. Albert refers to God only twice, declaring only that God is "not finite," "not a body" and "not measurable." Grant points out that "In theological treatises, it was common to involve God with space, place and vacuum" (2001, p. 194), but St. Albert does not do this in his discussion of space and the vacuum.

I have to say I am not persuaded by Grant's reasoning here. What Grant forgets is that St. Albert was not writing a theological treatise, but a book on physics. Obviously, different ground rules apply in the two cases. The ground rule which I am suggesting St. Albert followed when doing natural philosophy is that God could be legitimately invoked to explain natural phenomena that can be shown to have occurred, if the natural light of reason points to Him as the ultimate explanation of those phenomena.

I'd like to close with quotes from two unimpeachable sources on the natural philosophy of St. Albert the Great. The first is a quote from the article on Albertus Magnus in the 1906 Jewish Encyclopedia, which contends that St. Albert was heavily influenced by the writings of the Jewish philosopher Maimonides:

Following Maimonides, who refutes the proofs produced by the Peripatetics concerning the eternity of the world ("Physics," viii. 1, chap. xi.; "Summa Theologiae," ii. 1, 4, 3; compare "Moreh," ii. 14), Albertus is of [the] opinion that the eternity of the world must be rejected principally for this reason, that, if any one accepts the views of the Peripatetics, the world would have been evolved by natural force, and would, therefore, not be the work of a Creator acting with liberty and intention ("Physics," viii. 1, chap. xiii.; compare "Moreh," ii. 19, 24).

The foregoing quote, which cites St. Albert's commentary on Aristotle's Physics, shows that St. Albert was very concerned to keep God at the center of science, even as he confined himself to what reason could establish about God, from empirical phenomena in the natural world. The last thing Albert wanted was a godless natural philosophy.

My second quote is from an address in English given by Pope Benedict XVI in Vatican Square, on 24 March 2010:

Albert was canonized and declared a Doctor of the Church by Pope Pius XI, and Pope Pius XII named him the patron of the natural sciences. Saint Albert shows us that faith is not opposed to reason, and that the created world can be seen as a "book" written by God and capable of being "read" in its own way by the various sciences. His study of Aristotle also brought out the difference between the sciences of philosophy and theology, while insisting that both cooperate in enabling us to discover our vocation to truth and happiness, a vocation which finds its fulfillment in eternal life.

But if the world is a book written by God, which the various sciences are meant to read, then it should be quite clear that in St. Albert's natural philosophy, the notion of God is absolutely pivotal.

I conclude that Grant, in his portrayal of St. Albert as someone who tried to minimize the role of theology in science, is attempting to pigeon-hole the saint into a philosophical box which does not reflect St. Albert's own thinking.

4. St. Thomas Aquinas on the legitimate place of God in science

Image of St. Thomas Aquinas (1225-1274) depicted in stained glass. Courtesy of Wikipedia.

St. Thomas Aquinas (1225-1274) is generally considered to be the Catholic Church's greatest theologian and philosopher. Aquinas also wrote extensive commentaries on Aristotle's scientific works, and was a student of St. Albert the Great, who as we have seen was an accomplished scientist. If I can demonstrate that Aquinas rejected the tenets of methodological naturalism, this should effectively puncture the myth that methodological naturalism was an accepted principle of medieval science.

I will be citing passages from Aquinas' writings below. However, in order to refute any possible accusations that I am being selective in my citations, I would like begin by quoting from two Thomist scholars whose credentials are unimpeachable: the renowned scholars Ralph McInerny and John O'Callaghan, whose article, Aquinas appears in The Stanford Encyclopedia of Philosophy. The authors describe Aquinas' view of natural science in the following terms:

The concern of natural science is of course natural things, physical objects, which may be described as "what come to be as the result of a change and undergo change." The first task of natural philosophy, accordingly, is to define and analyze physical objects.
(McInerny, Ralph and O'Callaghan, John, "Saint Thomas Aquinas", The Stanford Encyclopedia of Philosophy (Winter 2010 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/win2010/entries/aquinas/. The above quote is taken from section 6 of the article.)

This is precisely what Aquinas himself says in his Commentary on Aristotle's Physics, where he writes:

3. ... And because everything which has matter is mobile, it follows that mobile being is the subject of natural philosophy. For natural philosophy is about natural things, and natural things are those whose principle is nature. But nature is a principle of motion and rest in that in which it is. Therefore natural science deals with those things which have in them a principle of motion.
(Commentary on Aristotle's Physics, Book 1, Lecture 1.)

At first blush, it might appear as though Aquinas is espousing a form of methodological naturalism here, but in fact, all Aquinas is saying is that the subject matter of natural science is physical objects. If we recall the various claims that we examined in Part A above, Aquinas' claim here is equivalent to principle (b), whereas methodological naturalism (as we saw) makes a much stronger claim. The assertion that science is about physical objects in no way entails that scientific explanations have to be confined to natural objects. And in fact, Aquinas himself famously maintained (in his first proof of the existence of God in the Summa Theologica, I, q. 2, art. 3) that movement in the world could only be explained by positing an incorporeal Unmoved Mover as the ultimate explanation of motion. To quote McInerny and O'Callaghan again:

... But let us first lay out Thomas's view of metaphysics. His question is Aristotle's: is there any science beyond natural science and mathematics? If to be and to be material are identical, then the science of being as being will be identical with the science of material being. That is what Aristotle rejects in the passage just quoted. It is in the course of doing natural philosophy that one gains certain knowledge that not everything that is is material. At the end of the Physics, Aristotle argues from the nature of moved movers that they require a first unmoved mover. If successful, this proof establishes that there is a first mover of all moved movers which is not itself material. Furthermore, the discussion of intellect in On the Soul III to which we alluded in the preceding paragraph, points beyond the material world. If the activity of intellect provides a basis for saying that, while the human soul is the substantial form of the body, it can exist apart from the body, that is, survive death, it is an immaterial existent. The Prime Mover and the immortal souls of human beings entail that to be and to be material are not identical. Since these are acquisitions at the limit of natural philosophy, they represent possible objects of inquiry in their own right. This is pre-eminently the case with the Prime Mover.
(McInerny, Ralph and O'Callaghan, John, "Saint Thomas Aquinas", The Stanford Encyclopedia of Philosophy (Winter 2010 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/win2010/entries/aquinas/. The above quote is from section 9.)

This is what Aquinas says in Book VIII of his Commentary on Aristotle's Physics, where he writes:

1069. Having shown that in things moved by another there is not a process to infinity but a first must be reached which is either immobile or a mover of self, and having shown that, of a thing that moves itself, one part is an immobile mover, and that, consequently, in either case there is a first mover that is immobile, now, because among self-movers which exist among us, namely, perishable animals, it happens that the motion-causing part in the thing which moves itself is perishable and moved per accidens, namely, the soul, the Philosopher [Aristotle] wishes to show here that the first mover is imperishable and is not moved either per se or per accidens.
Commentary on Aristotle's Physics, Book 8, Lecture 12

Later in the same lecture, Aquinas concludes that the Unmoved Mover is one:

1076. ...Therefore, it is absolutely necessary that the first mover be one and perpetual. But an immobile mover that is moved per accidens is not perpetual, as has been said above. It remains, therefore, that the first mover is utterly immobile, both per se and per accidens.
Commentary on Aristotle's Physics, Book 8, Lecture 12

For Aquinas, then, science (or natural philosophy) can prove the existence of an Unmoved Mover of all material things, which is not itself material. Science can also show that the human intellect is not material. Both of these claims directly contradict the tenets of methodological naturalism.

In their article, McInerny and O'Callaghan carefully explain that in the teaching of St. Thomas Aquinas, science can arrive at an indirect knowledge of God:

... Separate substance, divine being, is not directly accessible for our inspection or study. We come upon our first secure knowledge of God in the proof of the Prime Mover. Tantalizingly, once seen as a necessary requirement for there being any moved movers, the Prime Mover does not become a thematic object of inquiry in natural philosophy. One obvious reason for this is that such an entity is not an instance of the things which fall under the scope of the science. Knowledge of it comes about obliquely and indirectly. The same restriction is operative when the philosopher turns his culminating attention to the deity. How can he know more about the first cause of things? If the Prime Mover is known through moved movers as his effects, any further knowledge of him must be through his effects. It is by describing the effect as widely as possible that one seeks to come to a knowledge of the first cause unrestricted by the characteristics of mobile things. That characterization is being as being. The subject of metaphysics is being in all its amplitude in order to acquire a knowledge of the cause of being that will be correspondingly unbounded. (Quoted from section 9.)
(McInerny, Ralph and O'Callaghan, John, "Saint Thomas Aquinas", The Stanford Encyclopedia of Philosophy (Winter 2010 Edition), Edward N. Zalta (ed.), URL = http://plato.stanford.edu/archives/win2010/entries/aquinas/. Quoted from section 9.)

Our scientific knowledge of God, then, is indirect: we infer His existence from the study of bodies. But the key point here is that Aquinas recognizes that God's existence is scientifically knowable. In other words, Aquinas was clearly not a methodological naturalist.

I hope that the evidence I have adduced above will discredit once and for all the absurd thesis that methodological naturalism was a recognized rule of science in the Middle Ages.

5. Was there a decline in supernaturalism after the Middle Ages?

In his 2003 essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, edited by David C. Lindberg, Ronald L. Numbers, Chicago: University Of Chicago Press) Ronald Numbers contends that supernaturalism gradually gave way to naturalism, following the end of the Middle Ages:

For ordinary folk the most compelling instances of supernaturalism giving way to naturalism occurred not in physics or chemistry but in such areas as meteorology and medicine, in explanations of epidemics, eclipses, and earthquakes. Already by the sixteenth century, supernatural explanations of disease had largely disappeared from medical literature except in discussions of epidemics and insanity, which remained etiological mysteries, and venereal diseases, the wages of sin. In writing about the common afflictions of humanity—fractures, tumors, endemic diseases, and such—physicians seldom mentioned God or the devil. Even when discussing the plague, the most dreaded disease of all, they tended merely to acknowledge its supernatural origin before passing quickly to its more mundane aspects. The great French surgeon Ambroise Pare (1510-90), for example, explicitly confined himself to "the natural causes of the plague," saying that he would let divines deal with its ultimate causes. Priests and theologians may have placed greater emphasis on supernatural causes and cures, but in general they too easily accommodated new medical knowledge by maintaining that God usually effected His will through natural agencies rather than by direct intervention. Theological interests thus seldom precluded searching for natural causes or using natural therapies. (Numbers, 2003, p. 269.)

Earthquakes in the Middle Ages

It is widely assumed that people in the Middle Ages saw earthquakes as evidence of Divine displeasure. However, recent evidence suggests otherwise. A paper entitled, "Man and Natural Disaster in the Late Middle Ages: The Earthquake in Carinthia and Northern Italy on 25 January 1348 and its Perception" by Christian Rohr (Environment and History 9(2003): 127-149) discusses a major earthquake that occurred in Europe, at the time of the Black Death. I shall quote the abstract here:

How did people react to natural abnormalities such as earthquakes and floods in the Middle Ages? Why did they experience them as disasters? How did they explain them? Did they really see them as a divine punishment? Reports of the earthquake of 1348, which was followed by a landslide and a flood destroying the city of Villach, were often combined with accounts of the Black Death, which arose in these regions just a few weeks later.

There are still only a few studies of natural disasters in the Middle Ages, and for the eastern Alpine regions only the earthquake of 25 January 1348 has been examined in detail, albeit using a variety of approaches. This study tries to provide a mentality-bound approach, searching for the mentalities of the people, but without claiming to write a 'history of mentalities'. Nevertheless, it seems easier to examine mentalities in extreme situations than in normal times, though the records concerning natural disasters in the Late Middle Ages are mostly brief.

By re-visiting the sources for the 1348 earthquake following the studies of Borst (1981) and Hammerl (1992) and looking at aspects of its perception, management and explanation, this article calls into question the supposed 'medieval' equation of natural disaster and divine punishment. In spite of the fact that the natural disasters and Black Death were mixed up in the sources, there is little evidence that the earthquake itself was experienced as anything other than something tremendous and unexpected, but which also belonged to daily life.

A Witch's Eclipse (1349)

I am indebted to for the following account of a medieval eclipse, which shows that educated people in the Middle Ages were well aware that eclipses were natural phenomena.

On June 30, 1349, there was a total eclipse of the Moon visible in London, which Archdeacon Churton connects with the following incident:

The worthy Archbishop Bradwardine, who flourished in the reign of the Norman Edwards, and died A.D. 1349, tells a story of a witch who was attempting to impose on the simple people of the time. It was a fine summer's night, and the Moon was suddenly eclipsed. 'Make me good amends,' said she, 'for old wrongs, or I will bid the Sun also to withdraw his light from you.' Bradwardine, who had studied with Arabian astronomers, was more than a match for this simple trick, without calling in the aid of the Saxon law. 'Tell me', he said, 'at what time you will do this, and we will believe you; or if you will not tell me I will tell you when the Sun or the Moon will next be darkened, in what part of their orb the darkness will begin, how far it will spread, and how long it will continue.'

The story itself illustrates the fact that "simple people of the time" continued to believe that eclipses were supernatural phenomena, and the Website above, in its accounts of medieval eclipses (Famous Eclipses of the Middle Ages - Part One and Part Two) describes several incidents in which eclipses were interpreted by common folk - and even by kings, until the twelfth century - as bad omens. (In some cases, eclipses even caused kings to drop dead of shock.)

The point I wish to make, however, is that the decline in supernatural interpretations of eclipses was already well under way by the late Middle Ages, and that it was caused by the proliferation of medieval astronomy, which the Church took an active role in promoting, after acquiring from the Arabs the skills required to predict the movements of the celestial bodies with a high degree of accuracy.

Numbers also cites evidence of an increasing tendency by scientists to appeal to mechanical laws in order to explain events:

Enthusiasm for the naturalistic study of nature picked up in the sixteenth and seventeenth centuries as more and more Christians turned their attention to discovering the so-called secondary causes that God employed in operating the world. The Italian Catholic Galileo Galilei (1564-1642), one of the foremost promoters of the new philosophy, insisted that nature "never violates the terms of the laws imposed upon her." (Numbers, 2003, p. 267)

E. Was Methodological Naturalism a Product of the Scientific Revolution in the 16th and 17th centuries?

A joker playing card. Image courtesy of David Bellot and Wikipedia.

A standard pack of cards has two jokers. The joker is meant to represent a figure of fun, who should not be taken too seriously. In this section, I'm going to examine the testimony of two professors - Professor Robert Pennock and Professor John Haught - on methodological naturalism, at the 2005 Dover trial. The testimony of these two professors persuaded presiding Judge John E. Jones that methodological naturalism had been part-and-parcel of scientific methodology since the the scientific revolution of the 16th and 17th centuries. I will argue below that the testimony of these two professors is so full of factual errors that it cannot be taken seriously. It is a joke. Hence my description of these two learned men as "jokers."

1. Is Professor Robert Pennock right in portraying methodological naturalism as a reaction to medieval belief in magic?

Professor Robert T. Pennock is a philosopher working on the Avida digital organism project at Michigan State University. Pennock was called as an expert witness in the Kitzmiller v. Dover Area School District trial, testifying that methodological naturalism, which explains observable events in nature only by natural causes, without assuming the existence or non-existence of the supernatural, is a defining feature of the scientific method. Professor Pennock's testimony on methodological naturalism strongly influenced presiding Judge John E. Jones III, who cited it in his decision:

Expert testimony reveals that since the scientific revolution of the 16th and 17th centuries, science has been limited to the search for natural causes to explain natural phenomena. (9:19-22 (Haught); 5:25-29 (Pennock); 1:62 (Miller)). This revolution entailed the rejection of the appeal to authority, and by extension, revelation, in favor of empirical evidence. (5:28 (Pennock)). Since that time period, science has been a discipline in which testability, rather than any ecclesiastical authority or philosophical coherence, has been the measure of a scientific idea's worth. (9:21-22 (Haught ); 1:63 (Miller)). In deliberately omitting theological or "ultimate" explanations for the existence or characteristics of the natural world, science does not consider issues of "meaning" and "purpose" in the world. (9:21 (Haught); 1:64, 87 (Miller)). While supernatural explanations may be important and have merit, they are not part of science. (3:103 (Miller); 9:19-20 (Haught)). This self-imposed convention of science, which limits inquiry to testable, natural explanations about the natural world, is referred to by philosophers as "methodological naturalism" and is sometimes known as the scientific method. (5:23, 29-30 (Pennock)). Methodological naturalism is a "ground rule" of science today which requires scientists to seek explanations in the world around us based upon what we can observe, test, replicate, and verify. (1:59-64, 2:41-43 (Miller); 5:8, 23-30 (Pennock)).

In his testimony at the Dover trial in 2005, Professor Robert Pennock drew a link between the rise of methodological naturalism and and a decline in the medieval belief in magic. Until the 15th century, even educated people generally attributed sickness, bad weather and other misfortunes to supernatural beings (e.g. evil spirits, or an angry God). Only gradually did they come to attribute these calamities to to natural causes.

Professor Pennock cited two particular fields of science as examples, in his trial testimony: medicine (in which, he claimed, the popular belief that diseases were caused by evil spirits gave way to the scientific belief that diseases had entirely natural causes) and meteorology (where the belief that God sent lightning bolts and bad weather as expressions of His displeasure was replaced by the belief that weather could be understood in neutral, scientific terms).

(i) Did the search for natural causes of disease lead to the rise of methodological naturalism in medicine?

Hippocrates, the Father of Western medicine. Engraving by Peter Paul Rubens, 1638. Courtesy of the National Library of Medicine and Wikipedia.

In his medical testimony, Pennock portrayed the Greek physician Hippocrates (c. 460-370 B.C.) as a lone voice of reason whose naturalistic approach to disease was rapidly extinguished by a tide of religious superstition, in which supernaturalism reared its ugly head again. During the 13th to the 15th centuries, he contends, it was thought that the only way of overcoming the laws of nature was by appeal to supernatural entities. This kind of crude, supernaturalistic thinking held sway until the resurgence of a rational approach to disease in the 15th century. After that, says Pennock, the Scientific Revolution and the Enlightenment led to a rejection of religious authorities and their primitive, supernaturalistic explanations, in favor of an appeal to the empirical evidence from Nature. Allow me to quote the relevant passage from Pennock's testimony (Kitzmiller v. Dover Area School District; Trial transcript: Day 3 (September 28), AM Session, Part 1):

Epilepsy was the example that Hippocrates dealt with. It was called the sacred disease. The idea was that it was kind of divine possession when one went into an epileptic seizure. Hippocrates suggested that we should not think of it in that way but just think of it as a normal illness and try to find a normal, natural way of curing it. As he talked about epidemics, again epidemics would have been things that under some non-scientific ways of thinking about it they're the result of displeasure of God perhaps, and Hippocrates said we should try to find by cataloging natural regularities try to find causes for epidemics.

So that's sort of an early inkling of this, and it's not as though this then set root and established everything. One go through really century by century before one finds these things being teased apart. So for example really in the 13th through 15th century one finds alchemists, people doing supernatural magic, trying to think that one can find ways of overcoming the laws of nature by appeal to supernatural entities and so on.

And a switch that kind of happened of the same sort where people suggested well, maybe there are just hidden regularities that we don't yet know about that are actually natural explanations for these apparent magical things. So they talked about the natural magic, and the idea then was let's think about what these might be. Now, it's not as though they got things right. Facchino was one 15th century natural magic proponent who thought that influences from the planets of particular sorts could explain events on earth. He wasn't thinking of these as supernatural. He thought of them as natural, but that they could be controlled by other material, talismans for example.

So there you're getting this notion of a method that assumes natural regularities and appeal to those as coming out. Really this gets much more firmly established then in enlightenment and scientific revolution. That's probably what's most characteristic of the scientific revolution, rejecting appeal to authority and saying we will appeal just to nature itself. We'll appeal just to the evidence, the empirical evidence.

And it's very clear at that point then that when one does science, one is setting aside questions about whether the gods or some supernatural beings had some hand in this.

The reader might be wondering: is Pennock's narrative broadly accurate, or is it "Whig history" at its worst? Does Pennock paint a fair and balanced portrait of the rise of modern medicine, or is he engaging in myth-making? At this point, it might be a good idea to ask oneself a simple question: how did medieval physicians explain disease? Did they really attribute it to supernatural beings (e.g. demons, or an angry God), as Pennock alleges? Let's start by looking at epilepsy.

(a) How did medieval physicians explain epilepsy?

See http://www.thinkingchristian.net/2011/03/regularism-a-better-alternative-to-methodological-naturalism/

In researching the question of what educated people believed about epilepsy in the Middle Ages, I decided to consult Medieval Medicine: A Reader (Readings in Medieval Civilizations and Cultures) (University of Toronto Press, 2010) edited by Faith Wallis. I was pleasantly surprised to find that medieval physicians were well aware that epilepsy was a disease with a natural origin. For example, here is a quotation from Chapter 22 of the Breviary of the Practice of Medicine (Brevarium practicae medicinae), by the medieval physician Arnau of Vilanova (1235-1311):

I hold that epilepsy is an occlusion of the chief ventricles of the brain with loss of sensation and motion; or epilepsy is a non-continuous spasm of the whole body. This disease takes its rise from various causes, such as superfluous foods of drinks, or poisons, the bites of mad dogs or reptiles, from poisoned, corrupt, and pestiferous air. When the pores are constricted, and superfluities are retained, and natural heat is lessened, there follows a filling up of the chief ventricles of the brain. And these are the three causes which principally induce epilepsy. (Quoted in Wallis, p. 264.)

And here is Bernard of Gordon (1250-1318), writing in his Lily of medicine (Lilium medicinae), Part 2, chapter 25:

Epilepsy is a disease of the brain, removing sensation, motion and erection from the whole body, accompanied by a very serious disturbance of movement, because of an occlusion made in the non-principal ventricles of the brain.

The cause of this disease is a humor or windiness occluding the non-principal ventricles of the brain, impeding the passage of breath to the members, and therefore [the patient] is driven to fall suddenly to the ground. He feels absolutely nothing, nor can he in any way stand erect, but necessarily falls, unless the epilepsy be very mild, as will be seen. The movement of the hands and feet is agitated, disordered, and so is the breathing. Therefore, because of the disturbance in the breathing, there is always foam in the mouth...

Epilepsy, then, comes from either a secret cause or from some antecedent and remote cause. This is said because it sometimes comes from the brain, sometimes from the other parts, since the evil, poisonous fumes sometimes ascend from the chest to the head, occluding the ventricles, and so induce a paroxysm of epilepsy. Sometimes it comes from the stomach, sometimes from the liver, the spleen, the kidneys, the intestines, the bladder, the feet, hands or thumb. (Quoted in Wallis, pp. 265-266.)

Well, I can't find anything about demons here. It all sounds pretty naturalistic to me, without falling into the pretentious claims of methodological naturalism. So much for the idea of Hippocrates' lone voice of reason whose views were silenced by suoerstitious people in the Middle Ages.

(b) More nonsense from Professor Pennock: medieval Christians explained the Black Death as a punishment for sin, sent by an angry God

An image from The Dance of Death in the German printed edition, folio CCLXI recto from Hartman Schedel's Chronicle of the World (Nuremberg, 1493). The image is thought to have been created by Michael Wolgemut, and not by Hans Holbein the Younger, as often stated. Image courtesy of Wikipedia.

Professor Pennock's distortions do not end there. I'd like to quote from a 1997 essay that Pennock wrote wrote for the "Naturalism, Theism and the Scientific Enterprise" Conference (March 20-23, 1997) at the University of Texas at Austin, entitled, Supernaturalist Explanations and the Prospects for a Theistic Science or "How do you know it was the lettuce?" In his paper, Pennock included a section, "History of supernatural explanation", from which I shall cite a brief excerpt:

Perhaps it is a Neitzschian (sic) will to power that underlies our paradoxical desires both for understanding and for the mysterious, and that leads us to belief in the possibility of supernatural explanations. We desire understanding in part because of the control that it may give us. Knowledge is power, as Bacon said, and with it we feel more in charge of our own fates and sometimes the fates of others as well....

One of the earliest forms of supernatural explanation was animistic religion, which populates the world with gods... In later religious forms the gods have a more independent existence and may have more fully developed personalities. The Homeric epics reveal that for the ancient Greeks the world was populated by a panoply of competing gods and goddesses who regularly, sometimes kindly and sometimes cruelly, would intervene in the world and in human affairs. Homer explains how the fates of battling armies on the ground were often decided by the favors or jealousies of the Olympian gods watching and exercising control from above for their own purposes.

The switch to monotheism saw no change in this sort of use of supernatural explanation. Yahweh was regularly moved to anger, even towards his chosen people, and in His wrath would bring forth destruction and pestilence. In the mid-14th century, Christians in much of Europe tried to make wholesale atonement for their sins, that they thought must have led Yahweh to set upon them the Plague of Black Death.

Is Pennock factually correct here? Did Christians really explain the Black Death as a punishment for sin? To answer this question, I decided to look at what Christian physicians said on the matter. These physicians, like their contemporaries, firmly believed in the supernatural. If they didn't ascribe the Black Death to the wrath of God, but ascribed it to natural causes instead, then it would obviously be wrong to claim, as Pennock does, that the rise of medical science was achieved only when people were willing to reject supernaturalistic explanations of natural phenomena. What it would suggest instead is that people, even back then, were careful about invoking supernaturalistic explanations, refraining from doing so until all natural alternatives had been exhausted. But as I explained in Part A above, that's not methodological naturalism. That's simply a principle of prudence: don't invoke the supernatural unless you have no other alternative.

Bearing that in mind, let us now examine how Christian physicians in the 14th century viewed the Black Death.

Did Christian physicians in the 14th century explain the Black Death as a plague sent by God?

An article entitled, "Medicine, Theoretical", in Medieval Science, Technology, and Medicine: An Encyclopedia edited by Thomas F. Glick, Steven John Livesey and Faith Wallis (Routledge: New York and London, 2005) describes how medieval physicians viewed disease, and demonstratively that they attempted to explain the Black Death in naturalistic terms, as a contagious disease, and not as a Divine visitation for sin:

In manuals of theory such as the Isagoge, ... disease states are classified into three broad categories: (1) Mala complexio or disorders of temperament (humoral imbalance); (2) Mala compositio or congenital defect; and (3) Solutio continuatis, "breach of continuity" or trauma. Thus disease was not precisely an entity in Galenic medicine, but an event (accident) or state. Drawing on Aristotelian hylomorphism, doctors defined health and disease as "forms determining matter"; hence medieval physicians regarded as disease what a modern would term clinical presentation or symptom. Such disease specificity as exists in medieval medical theory lies closer to the modern concept of the syndrome: hence, a morbus was a disease of mala complexio with a proper name designating a particular cluster of symptoms (e.g. gout. leprosy, migraine). Ontologically, this was a fairly weak concept, because a morbus could manifest differently in patients of different complexion, and one morbus could change into another. Leprosy presented an interesting challenge to this model. Particularly in the fourteenth and fifteenth centuries, and apparently in response to increasing demands on the medical profession for expert opinion in accusations of leprosy, authors such as Gilbertus Anglicus and Jordanus de Turre concentrated on cataloguing the features of leprosy that were definitive and invariable. The Black Death posed a different kind of problem, for its universal scope defied the Hippocratic model of an epidemic as a local outbreak of acute and virulent disease. Learned commentators invoked cosmological explanations based on the notion of a global infectio or tainting of the atmosphere, with consequent poisoning of the soil, water, foodstuffs etc. over wide regions. Although plague might be caused by environmental factors, it was understood to spread through contact (contagio).

Professor Pennock asserted, in the passage I quoted above, that "In the mid-14th century, Christians in much of Europe tried to make wholesale atonement for their sins, that they thought must have led Yahweh to set upon them the Plague of Black Death." I have to say I can't find anything about plagues sent by Yahweh here!

I am therefore forced to conclude that Professor Pennock has played fast and loose with his facts - and that's putting it kindly. The upshot of my research has led me to believe that Christian physicians were sensible people who looked for natural causes for diseases first, before considering the possibility of a supernatural explanation.

The reader might want to ask: what about ordinary folk? Did they regard the Black Death as a punishment for sin? The question has little relevance, as it is the conditions that led to the rise of medicine as a science that we are discussing here, which means that we should be focusing our attention on what doctors believed, then and now, about disease. However, the reader will be interested to know that even the common folk did not rush headlong into supernaturalistic explanations of the Black Death. Instead, they looked for natural explanations first. Perceiving that 14th century healers were unable to successfully explain the cause of the Black Death, Europeans turned to astrological forces, earthquakes, and the poisoning of wells by Jews as possible reasons for the plague's emergence. Ssdly, hundreds of Jewish communities were exterminated because of this slanderous accusation against them - an accusation which was denounced time and again as a baseless calumny by Popes in the late Middle Ages. (See J. M. Bennett and C. W. Hollister, Medieval Europe: A Short History, New York: McGraw-Hill, 2006, p. 326.)

(ii) Was the rise of meteorology tied to a rejection of supernatural explanations?

Lightning bolts hitting Atlanta skyscrapers on 9 June 2008. Image courtesy of David Selby and Wikipedia.

I haven't finished with Professor Pennock yet. In his testimony at the Dover trial of 2005 (Kitzmiller v. Dover Area School District; Trial transcript: Day 3 (September 28), AM Session, Part 1), Professor Pennock cited one other area of science in which a supernaturalistic approach gave rise to an exclusively naturalistic one: meteorology. Once upon a time, he tells us, people believed lightning bolts were sent by an angry God. Then along came Benjamin Franklin, who explained them in naturalistic terms, and the science of meteorology has never looked back since. As Pennock puts it:

A classic example had to do with meteorological phenomenon, lightning. It would have been thought or that lightning perhaps would have been an expression of God's displeasure, right? That God by design would send lightning somewhere, and it was one of the founding fathers, Benjamin Franklin of course, who investigated lightning under this assumption of methodological naturalism and said you can have a natural explanation of lightning, it's electricity.

And that's an example of this shift, a shift as saying we're not going to say what God may or may not be doing with sending lighting bolts. We'll simply say let's examine this as part of the natural laws of nature.

Well, did it happen that way? Did educated people in the Middle Ages really believe that lightning was caused by the wrath of God? As the reader might have guessed from Pennock's previous unsuccessful forays into history, the answer is a firm "No." According to the article on "Meteorology" in Medieval Science, Technology, and Medicine: An Encyclopedia, edited by Thomas F. Glick, Steven John Livesey and Faith Wallis (Routledge: New York and London, 2005), people favored naturalistic explanations for bad weather:

In general, Aristotelian concepts were prominent in medieval writings on meteorology, although they were frequently adapted, altered, and transformed. In both antiquity and the Middle Ages, naturalistic explanations for the weather were favored. As a result, the idea that lightning or thunder had Divine origins was widely rejected or ignored.

I am forced to conclude, then, that Professor Pennock's account of the rise of methodological naturalism at the 2005 Dover trial is fundamentally unreliable, both in its chronology and its utterly false portrayal of the beliefs of people living in the Middle Ages. Pennock is utterly unconvincing when he claims that medieval scientists' willingness - even on rare occasions - to resort to supernatural explanations was what held back the rise of science in the sixteenth and seventeenth centuries. In Part Six, I will argue that long after the Scientific Revolution, scientists were still prepared to resort to supernaturalistic explanations in their work.

I'd like to conclude my discussion of Professor Pennock's Dover testimony by citing an embarrassing admission he makes in an essay he wrote for the "Naturalism, Theism and the Scientific Enterprise" Conference (March 20-23, 1997) at the University of Texas at Austin, entitled, Supernaturalist Explanations and the Prospects for a Theistic Science or "How do you know it was the lettuce?" The essay contains the following passage:

Also, though religions have probably included supernatural explanation most systematically, they are not alone in this predilection. Until just the 19th century even the natural philosophers and scientists who studied the world would often include supernatural elements in their theories.

Here, Pennock is admitting that as late as the 19th century, methodological naturalism was not viewed by scientists as a vital part of the scientific method! He then goes on to cite scientists from the past who invoked the supernatural, including:

• Isaac Newton (1642-1727), who "held that atoms and the laws they obeyed were fixed at Creation by God";

• 19th century British geologists, "many of whom were also clergymen," who "spent much of their time searching for evidence of the global flood" in the course of their research on behalf of the Geological Society, until its President, Adam Sedgwick, recanted from this view in 1831;

• 19th century British naturalists, who "agreed that the biological world was specially created through God's supernatural agency" until Darwin's theory was published in 1859; and finally,

• Alfred Russel Wallace (1823-1913), who "allowed that human beings had evolved, but under the direction of spirit beings."

I'd now like to contrast Pennock's frank admission that methodological naturalism did not become a generally accepted part of the scientific method until the late nineteenth century with the statement made by presiding Judge John E. Jones III, who cited it in his finding on whether Intelligent Design is Science:

Expert testimony reveals that since the scientific revolution of the 16th and 17th centuries, science has been limited to the search for natural causes to explain natural phenomena. (9:19-22 (Haught); 5:25-29 (Pennock); 1:62 (Miller)). This revolution entailed the rejection of the appeal to authority, and by extension, revelation, in favor of empirical evidence. (5:28 (Pennock)). Since that time period, science has been a discipline in which testability, rather than any ecclesiastical authority or philosophical coherence, has been the measure of a scientific idea's worth. (9:21-22 (Haught ); 1:63 (Miller)).

I wonder if Judge Jones would have made the same summing up if he had been aware of Professor Pennock's damaging admission, in an essay he wrote in 1997, that methodological naturalism was openly flouted by geologists and biologists well into the nineteenth century, and by Wallace in the late nineteenth century. As they say, we'll never know.

2. Professor Haught's flawed claim that methodological naturalism goes back to Galileo and beyond

Left: Nicolaus Copernicus (1473-1543). Portrait from Town Hall in Thorn/Torun - 1580. Right: Galileo Galilei (1564-1642). Portrait by Ottavio Leoni, 1624. Detail. Images courtesy of Nicholaus Copernicus Museum in Frombork and Wikipedia.

John F. Haught is a Catholic theologian and Senior Research Fellow at the Woodstock Theological Center at Georgetown University. I feel compelled to add for the record that Haught rejects the Catholic doctrine that Jesus was born of a virgin. The Catechism of the Catholic Church on the other hand states: "From the first formulations of her faith, the Church has confessed that Jesus was conceived solely by the power of the Holy Spirit in the womb of the Virgin Mary" (Part One, Section Two, Chapter Two, Article 3, paragraph 496.)

Professor Haught testified against the teaching of intelligent design in schools due to its religious nature in the case of Kitzmiller v. Dover Area School District in 2005. In the following excerpt from his testimony (Kitzmiller v. Dover Area School District Trial transcript: Day 5 (September 30), PM Session, Part 1) regarding methodological naturalism, Professor Haught argues that the decision to limit oneself to natural explanations has been a vital part of the way modern science is done, ever since its birth, which took place "roughly from the end of the 16th to the 17th Century." Especially significant in this regard is the figure of Galileo:

Q. You said that science seeks to understand the natural world through natural explanations. Is that important?

A. Yes, that's critical. The science, by definition, limits itself self-consciously, methodologically, to natural explanations. And that means that anything like a supernatural reality or transcendent reality, science is simply not wired to pick up any signals of it, and therefore any reference to the supernatural simply cannot be part of scientific discourse. And this is the way that science carries on to our present day.

Q. Would that mean this is the way modern science is conducted?

A. Modern science we date from roughly the end of the 16th to the 17th Century, in that period of time. And it was at that time that the great figurists of modern science, almost all of whom were deeply religious men themselves, decided self-consciously that this new mode of inquiry would not appeal to anything that's not natural, would not appeal to things like value, importance, divine causation, or even anything like intelligent causation.

These are not scientific categories of explanation. And ever since the 16th and 17th Century, modern science, as it's called, leaves out anything that has to do with theological or ultimate explanation.

Q. Who are some of the leading figures in the development of modern science?

A. Well, we can go back to Copernicus. And, of course, the figure that for me stands out is Galileo. And Galileo is important because he told his accusers, his ecclesiastical accusers, that we should never look for scientific information in Scripture, we should never look for scientific information in any theological source.

So he placed science on the foundation of experience rather than authority or philosophical coherence. From thence forth to this day, science is a discipline where testability is the criterion of its worth.

Professor Haught's argument is badly flawed on logical grounds. The fact that Scripture cannot tell us about science does not imply that science cannot tell us about God.

Haught is also wrong on historical grounds. Neither Copernicus nor Galileo could be described by any stretch of the imagination as methodological naturalists.

(a) Copernicus' whole approach to astronomy was grounded in his theology

Image of the heliocentric model from Nicolaus Copernicus' De revolutionibus orbium coelestium. Courtesy of Wikipedia.

In the Preface to his work De revolutionibus orbium caelestium (On the Revolutions of the Celestial Spheres, 1543), Copernicus explains that the motivation for his heliocentric hypothesis was theological. He believed that a universe that had been created by God for our sake must be comprehensible to the human mind. He states that he was forced to revive the long-forgotten heliocentric hypothesis, because it alone could yield knowledge of the movements of the heavenly bodies with the desired accuracy:

For a long time, then, I reflected on this confusion in the astronomical traditions concerning the derivation of the motions of the universe's spheres. I began to be annoyed that the movements of the world machine, created for our sake by the best and most systematic Artisan of all, were not understood with greater certainty by the philosophers, who otherwise examined so precisely the most insignificant trifles of this world. For this reason I undertook the task of rereading the works of all the philosophers which I could obtain to learn whether anyone had ever proposed other motions of the universe's spheres than those expounded by the teachers of astronomy in the schools. And in fact first I found in Cicero that Hicetas supposed the earth to move. Later I also discovered in Plutarch that certain others were of this opinion.

In the Introduction to his work De revolutionibus orbium caelestium (On the Revolutions of the Celestial Spheres, 1543), Copernicus expressed his conviction that anyone who diligently contemplates the order displayed in the movements of the celestial bodies will thereby come to admire "the Artificer of all things":

"For who, after applying himself to things which he sees established in the best order and directed by Divine ruling, would not through diligent contemplation of them and through a certain habituation be awakened to that which is best and would not admire the Artificer of all things, in Whom is all happiness and every good? For the divine Psalmist surely did not say gratuitously that he took pleasure in the workings of God and rejoiced in the works of His hands, unless by means of these things as by some sort of vehicle we are transported to the contemplation of the highest good." (Copernicus, Nicolaus, On the Revolutions of the Celestial Spheres, Thorn: Societas Copernicana, 1873, pp. 10-11).

In the following paragraph, Copernicus refers to astronomy as a "divine rather than human science" and favorably quotes the opinion of Plato, who was inclined to think that no-one lacking a knowledge of the heavenly bodies could be called godlike:

The great benefit and adornment which this art [astronomy - VJT] confers on the commonwealth (not to mention the countless advantages to individuals) are most excellently observed by Plato. In the Laws, Book VII, he thinks that it should be cultivated chiefly because by dividing time into groups of days as months and years, it would keep the state alert and attentive to the festivals and sacrifices. Whoever denies its necessity for the teacher of any branch of higher learning is thinking foolishly, according to Plato. In his opinion it is highly unlikely that anyone lacking the requisite knowledge of the sun, moon, and other heavenly bodies can become and be called godlike.

However, this divine rather than human science, which investigates the loftiest subjects, is not free from perplexities.
(Nicholas Copernicus, De Revolutionibus (On the Revolutions), 1543. Source: Translation and Commentary by Edward Rosen, The John Hopkins University Press, Baltimore and London. Adapted from Dartmouth College, MATC, Online reader.)

At the beginning of the Introduction to his great work, Copernicus even defines the science of astronomy in theological terms, as "the discipline which deals with the universe's divine revolutions, the asters' motions, sizes, distances, risings and settings, as well as the causes of the other phenomena in the sky, and which, in short, explains its whole appearance." (Nicholas Copernicus, De Revolutionibus (On the Revolutions), 1543. Source: Translation and Commentary by Edward Rosen, The John Hopkins University Press, Baltimore and London. Adapted from Dartmouth College, MATC, Online reader.)

In Chapter 8 of his De revolutionibus orbium caelestium (On the Revolutions of the Celestial Spheres, 1543), Copernicus even adduces theological arguments in favor of the stability of the universe and the daily rotation of the Earth, after listing several scientific arguments for these ideas:

As a quality, moreover, immobility is deemed nobler and more divine than change and instability, which are therefore better suited to the earth than to the universe... You see, then, that all these arguments make it more likely that the earth moves than that it is at rest. This is especially true of the daily rotation, as particularly appropriate to the earth. This is enough, in my opinion, about the first part of the question."
(Nicholas Copernicus, De Revolutionibus (On the Revolutions), 1543. Source: Translation and Commentary by Edward Rosen, The John Hopkins University Press, Baltimore and London. Adapted from Dartmouth College, MATC, Online reader.)

But it seems that Copernicus did not stop there. If the following quote is authentic, he actually equated the knowledge of the laws of science with Divine worship. Thus for Copernicus, scientific knowledge itself is a kind of prayer:

"To know the mighty works of God, to comprehend His wisdom and majesty and power, to appreciate, in degree, the wonderful working of His laws, surely all this must be a pleasing and acceptable mode of worship to the Most High, to whom ignorance cannot be more gratifying than knowledge."
(Reference unknown. Copernicus, as cited in Hubbard, Elbert, "Copernicus" (Vol. XVI, Jan. 1905, No. 1), in Little Journeys to the Homes of Great Scientists New York: The Roycrofters, page v. See also Poland: The Knight Among Nations (Fleming H. Revell Co., London & Edinburgh, Third edition, 1908) by Louis E. Van Norman, p. 290; Glory of The Stars (Pacific Press Publishing, Mountain Views, California, 1952), by Merlin L. Neff, Ph. D., pp. 191-192; and The Language of God: A Scientist Presents Evidence for Belief (2006) by Francis Collins, Free Press, 2006, pp. 230-31.)

Let us review the evidence. The motivation for Copernicus proposing his heliocentric hypothesis in the first place was a theological one. In his great treatise on astronomy, Copernicus voices his conviction that anyone who diligently contemplates the movements of the celestial bodies will be led thereby to a knowledge of God. He refers to astronomy as a "divine rather than human science," and he approvingly quotes Plato's statement that no-one who lacks a knowledge of the heavenly bodies can be called godlike. He even defines the science of astronomy in theological terms, as "the discipline which deals with the universe's divine revolutions." In Chapter 8 of the same work, Copernicus even puts forward theological arguments in favor of his scientific theory that the Earth rotates on its axis once a day. Finally, he equates scientific knowledge of the laws of Nature with prayer. Can anyone describe such a man as a methodological naturalist?

(b) Galileo believed that God's existence could be clearly discerned from His natural works

A Grey Crowned Crane (Balearica regulorum). Image courtesy of Aaron Logan and Wikipedia. According to Galileo, God personally designed the bones, veins, flesh and feathers of birds, in exquisite detail.

I'd like to begin my exposition of Galileo's views on the natural knowledge of God with a passage from Galileo's celebrated Letter to Madame Christina of Lorraine, Grand Duchess of Tuscany: Concerning the Use of Biblical Quotations in Matters of Science (1615):

... I think that in discussions of physical problems we ought to begin not from the authority of scriptural passages, but from sense-experiences and necessary demonstrations; for the holy Bible and the phenomena of nature proceed alike from the divine Word, the former as the dictate of the Holy Ghost and the latter as the observant executrix of God's commands. It is necessary for the Bible, in order to be accommodated to the understanding of every man, to speak many things which appear to differ from the absolute truth so far as the bare meaning of the words is concerned. But Nature, on the other hand, is in­exorable and immutable; she never transgresses the laws imposed upon her, or cares a whit whether her abstruse reasons and methods of operation are understandable to men. For that reason it appears that nothing physical which sense-experience sets before our eyes, or which necessary demonstrations prove to us, ought to be called in question (much less condemned) upon the testimony of biblical passages which may have some different meaning beneath their words. For the Bible is not chained in every expression to conditions as strict as those which govern all physical effects; nor is God any less excellently revealed in Nature's actions than in the sacred statements of the Bible. Perhaps this is what Tertullian meant by these words: "We conclude that God is known first through Nature, and then again, more particularly, by doctrine; by Nature in His works, and by doctrine in His revealed word."

In the passage above, Galileo speaks of the Bible and Nature as God's two books. But if the phenomena of nature constitute a book, then for Galileo, they must have had an Author. This contradicts the thesis of methodological naturalism, which asserts that natural phenomena can be fully explained without recourse to God.

In his letter to Grand Duchess Christina, Galileo waxes eloquent on Nature's ability to reveal God to us. He even equates the grandeur of this revelation with that of the revelation of God in the Bible: "nor is God any less excellently revealed in Nature's actions than in the sacred statements of the Bible." Finally, he approvingly quotes the words of Tertullian, that "God is known first through Nature" and that God is known "by Nature in His works." Does this sound like the way in which a methodological naturalist would write?

Because Nature is the "observant executrix of God's commands," She cannot possibly disobey those commands; hence, "she never transgresses the laws imposed upon her" by God. Galileo is not asserting here that the laws of Nature are fixed, but rather that Nature cannot violate the commands of Her Maker. Indeed, proof that Galileo could not have intended that the laws of Nature are invariant may be found in the same letter, where he discusses the miracle of Joshua's "long day." Although he entertain various hypotheses reagrding the mechanics of the miracle - e.g. did the Sun stand still, or did the primum mobile stop instead, causing the movement of all celestial bodies to come to a halt, as St. Augustine claimed? - what he never questioned, in his letter, was the reality of the miracle itself. This should suffice to refute the suggestion that Galileo was espousing some form of naturalism when he wrote that Nature "never transgresses the laws imposed upon her." This suggestion was put forward by Ronald Numbers in his essay, "Science without God: Natural Laws and Christian Beliefs" (in When Science and Christianity Meet, ed. by David C. Lindberg and Ronald L. Numbers, Chicago: University Of Chicago Press, 2003). It should be clear to the reader that Numbers has quoted Galileo out of context.

Another passage in Galileo's letter to Grand Duchess Christina indicates that he believed that God's greatness could be "marvelously discerned" from His natural works, especially by trained scientists who know what to look for when they study the heavens. Indeed, the universe contains so many hidden mysteries that "studies of hundreds upon hundreds of the most acute minds have still not pierced them." Once again, Galileo makes use of the metaphor of Nature as a book, which can only mean that the hidden mysteries contained in the heavens contain a special message which God wants human beings to discern. But the notion of God communicating a message to us through the works of Nature is totally at odds with the tenets of methodological naturalism, which claims that we can fully account for the works of Nature without invoking God:

... [T]o prohibit the whole science [of astronomy] would be but to censure a hundred passages of Holy Scripture which teach us that the glory and greatness of Almighty God are marvelously discerned in all His works and divinely read in the open book of Heaven. For let no one believe that reading the lofty concepts written in that book leads to nothing further than the mere seeing of the splendor of the sun and the stars and their rising and setting, which is as far as the eyes of brutes and of the vulgar can penetrate. Within its pages are couched mysteries so profound and concepts so sublime that the vigils, labors, and studies of hundreds upon hundreds of the most acute minds have still not pierced them, even after continual investigations for thousands of years. The eyes of an idiot perceive little by beholding the external appearance of a human body, as compared with the wonderful contrivances which a careful and practiced anatomist or philosopher discovers in that same body when he seeks out the use of all those muscles, tendons, nerves, and bones; or when examining the functions of the heart and the other principal organs, he seeks the seat of the vital faculties, notes and observes the admirable structure of the sense organs, and (without ever ceasing in his amazement and delight) contemplates the receptacles of the imagination, the memory, and the understanding. Likewise, that which presents itself to mere sight is as nothing in comparison with the high marvels that the ingenuity of learned men discovers in the heavens by long and accurate observation. And that concludes what I have to say on this matter.
(Letter to Madame Christina of Lorraine, Grand Duchess of Tuscany: Concerning the Use of Biblical Quotations in Matters of Science, 1615.)

Finally, the following passage from Galileo's work, The Assayer (1623), tells us that we need to study mathematics if we are to grasp the mysteries of the universe:

Philosophy is written in that great book which ever lies before our eyes — I mean the universe — but we cannot understand it if we do not first learn the language and grasp the symbols, in which it is written. This book is written in the mathematical language, and the symbols are triangles, circles and other geometrical figures, without whose help it is impossible to comprehend a single word of it; without which one wanders in vain through a dark labyrinth.
(The Assayer (1623), as translated by Thomas Salisbury (1661), p. 178, as quoted in The Metaphysical Foundations of Modern Science (2003) by Edwin Arthur Burtt, p. 75.)

But if the language of science is mathematical, then the Author must be a Master Mathematician, who is talking to us through symbols. Once again, Galileo's thinking is diametrically opposed to that of modern-day scientists who espouse methodological naturalism.

Galileo and Intelligent Design

It gets worse. It turns out that Galileo was something of an Intelligent Design theorist. Galileo often mused on what he saw as the stunning manifestations of God's creative wisdom. He was particularly impressed with birds and their ideal design for flight, and with fish and their perfect design for swimming in water:

God could have made birds with bones of massive gold, with veins full of molten silver, with flesh heavier than lead and with tiny wings... He could have made fish heavier than lead, and thus twelve times heavier than water, but He has wished to make the former of bone, flesh, and feathers that are light enough, and the latter as heavier than water, to teach us that He rejoices in simplicity and facility. (Sobel, Dava, Galileo’s Daughter: A Historical Memoir of Science, Faith, and Love. Toronto: Viking Press, 1999, p. 99.)

So according to Galileo, God not only personally designed fish, but He also designed the bones, veins, flesh and feathers of birds, in exquisite detail. What's more, He designed them in the way He did, in order to teach us something about Himself. But if you're a methodological naturalist, then you are committed to holding that natural phenomena can teach us nothing about the Creator, since natural causes are sufficient to account for them.

In Part Six, I will cite additional passages from Galileo's own writings, showing that he was a believer in cosmic miracles, that he held that the human mind had been created by God, and he believed that God personally spoke to him.

Concluding thoughts on the myth that methodological naturalism was the product of the Scientific Revolution

In Part E of this essay, I have cited "chapter and verse" to refute the widely peddled myth, still propagated by certain scholars who should know better, that methodological naturalism goes back to the Scientific Revolution of the sixteenthand seventeenth centuries. At the Dover trial of 2005, Presiding Judege John E. Jones swallowed this myth hook line and sinker when he declared in his finding on whether Intelligent Design is science:

Expert testimony reveals that since the scientific revolution of the 16th and 17th centuries, science has been limited to the search for natural causes to explain natural phenomena. (9:19-22 (Haught); 5:25-29 (Pennock); 1:62 (Miller)).

Still, old myths die hard, so I'd like to close by quoting the final paragraph of an essay by the late Professor Margaret Osler (1947-2010), a former Professor of history at the University of Calgary, in Galileo Goes to Jail and Other Myths about Science and Religion, edited by Ronald Numbers (Harvard University Press, 2009):

Seventeenth century natural philosophers were not modern scientists. Their exploration of the natural world was not cut off from their religious views and theological assumptions. That separation came later. Reading the past from the standpoint of recent developments has led to serious misunderstandings of the Scientific Revolution. For many of the natural philosophers of the seventeenth century, science and religion – or better, natural philosophy and theology – were inseparable, part and parcel of the endeavor to understand our world. (Osler, "Myth 10: Science and Religion in the Scientific Revolution," in Numbers, 2009, p. 98.)

Professor Margaret Osler's masterly summing up should shatter any lingering credibility that attaches to the testimonies of Professors Pennock and Haught during the Dover trial. It should be obvious to the unbiased reader that these learned men have badly mis-read the history of the Scientific Revolution, and that the methodological naturalism they falsely ascribe to the scientists of that period is a projection of their own minds.

St. Vitus' dance: http://matrix.msu.edu/hst/hst425/mats/waller_spin.pdf, https://www.msu.edu/~pennock5/research/papers/Pennock_BioAndRelgn.pdf (Pennock paper)

In this essay (Part Five of my reply to Zack Kopplin) I have eviscerated methodological naturalism as a principle for doing science, demonstrating that the arguments adduced in support of it are unconvincing and showing that it was not widely adopted by scientists until the late nineteenth century. In Part Six, I will go further and demonstrate that no less than thirty noted scientists from the sixteenth up to the nineteenth centuries violated methodological naturalism, a principle which is now commonly alleged to be indispensable to the practice of science.