How does Descartes try to extricate himself from the sceptical doubts that he has raised? Does he succeed?
[All page references and quotations from the Meditations are taken from
the 1995 Everyman edition]
In the Meditations, Descartes embarks upon what Bernard Williams has
called the project of 'Pure
Enquiry' to discover certain, indubitable foundations for knowledge. By
subjecting everything to
doubt Descartes hoped to discover whatever was immune to it. In order to
best understand how and
why Descartes builds his epistemological system up from his foundations
in the way that he does, it is
helpful to gain an understanding of the intellectual background of the
17th century that provided the
motivation for his work.
We can discern three distinct influences on Descartes, three conflicting
world-views that fought for
prominence in his day. The first was what remained of the mediaeval
scholastic philosophy, largely
based on Aristotelian science and Christian theology. Descartes had been
taught according to this
outlook during his time at the Jesuit college La Fleché and it had an
important influence on his work,
as we shall see later. The second was the scepticism that had made a
sudden impact on the intellectual
world, mainly as a reaction to the scholastic outlook. This scepticism
was strongly influenced by the
work of the Pyrrhonians as handed down from antiquity by Sextus
Empiricus, which claimed that, as
there is never a reason to believe p that is better than a reason not to
believe p, we should forget about
trying to discover the nature of reality and live by appearance alone.
This attitude was best
exemplified in the work of Michel de Montaigne, who mockingly dismissed
the attempts of
theologians and scientists to understand the nature of God and the
universe respectively. Descartes felt
the force of sceptical arguments and, while not being sceptically
disposed himself, came to believe
that scepticism towards knowledge was the best way to discover what is
certain: by applying sceptical
doubt to all our beliefs, we can discover which of them are indubitable,
and thus form an adequate
foundation for knowledge. The third world-view resulted largely from the
work of the new scientists;
Galileo, Copernicus, Bacon et al. Science had finally begun to assert
itself and shake off its dated
Aristotelian prejudices. Coherent theories about the world and its place
in the universe were being
constructed and many of those who were aware of this work became very
optimistic about the
influence it could have. Descartes was a child of the scientific
revolution, but felt that until sceptical
concerns were dealt with, science would always have to contend with
Montaigne and his cronies,
standing on the sidelines and laughing at science's pretenses to
knowledge. Descartes' project, then,
was to use the tools of the sceptic to disprove the sceptical thesis by
discovering certain knowledge
that could subsequently be used as the foundation of a new science, in
which knowledge about the
external world was as certain as knowledge about mathematics. It was
also to hammer the last nail
into the coffin of scholasticism, but also, arguably, to show that God
still had a vital rôle to play in the
discovery of knowledge.
Meditation One describes Descartes' method of doubt. By its conclusion,
Descartes has seemingly
subjected all of his beliefs to the strongest and most hyberbolic of
doubts. He invokes the nightmarish
notion of an all-powerful, malign demon who could be deceiving him in
the realm of sensory
experience, in his very understanding of matter and even in the simplest
cases of mathematical or
logical truths. The doubts may be obscure, but this is the strength of
the method - the weakness of
criteria for what makes a doubt reasonable means that almost anything
can count as a doubt, and
therefore whatever withstands doubt must be something epistemologically
formidable.
In Meditation Two, Descartes hits upon the indubitable principle he has
been seeking. He exists, at
least when he thinks he exists. The cogito (Descartes' proof of his own
existence) has been the source
of a great deal of discussion ever since Descartes first formulated it
in the 1637 Discourse on Method,
and, I believe, a great deal of misinterpretation (quite possibly as a
result of Descartes' repeated
contradictions of his own position in subsequent writings). Many
commentators have fallen prey to
the tempting interpretation of the cogito as either syllogism or
enthymeme. This view holds that
Descartes asserts that he is thinking, that he believes it axiomatic
that 'whatever thinks must exist' and
therefore that he logically concludes that he exists. This view, it
seems to me, is wrong. It should be
stated on no occasion, in the Meditations, does Descartes write 'I am
thinking, therefore I am', nor
anything directly equivalent. Rather, he says:
"Doubtless, then, that I exist…and, let him deceive me as he may, he can
never bring it about that I
am nothing, so long as I shall be conscious that I am something. So that
it must, in fine, be
maintained, all things being maturely and carefully considered, that
this proposition I am, I exist, is
necessarily true each time it is expressed by me or conceived in my
mind." (p. 80).
The point here is that it is impossible to doubt the truth of the
proposition 'I exist' when one utters it.
It is an indubitable proposition, and one that will necessarily be
presupposed in every attack of the
sceptic. Descartes is not yet entitled to use syllogisms as the
possibility of the malign demon is still
very much alive. As an aside, Descartes himself denies that the cogito
is a syllogism, although it
should be mentioned that in some of the Replies to Objections he seems
to assert that it is in fact a
syllogism. Finally, in the Regulae ad directionem ingenii, Descartes
denies the usefulness of
syllogisms as a means to knowledge.
I believe that, given Descartes' project, it is fair to grant him that
the cogito deserves the status he
bestows upon it. For can there be anything more certain than something
that is so forceful and so
powerful that every time it is presented to our mind we are forced to
assent to it?
What Descartes did here was to jiggle about the way philosophy normally
approaches the construction
of knowledge structures. By starting with self-knowledge, he elevates
the subjective above the
objective and forces his epistemology to rest upon the knowledge he has
of his own self (and
inadvertently sets the tone for the next 300 years of philosophy). This
leaves him with a problem. He
can know his own existence, that he is a thinking thing and the contents
of his consciousness, but how
can any of this ever lead to any knowledge of anything outside of
himself?
The answer is that, by itself, it can't. Descartes, in the third
Meditation, attempts to prove the
existence of God, defined as a being with all perfections. This proof is
to be derived from his idea of a
God, defined as a being with all perfections. So far, so good -
Descartes examines the contents of his
consciousness and discovers within it this idea, and we can allow him
this. At this point, however, he
introduces a whole series of scholastic principles concerning different
modes of causation and reality
without proper justification:
"For, without doubt, those [ideas considered as images, as opposed to
modes of consciousness] that
represent substances are something more, and contain in themselves, so
to speak, more objective
reality, that is, participate by representation in higher degrees of
being or perfection than those that
represent only modes or accidents; and again the idea by which I
conceive a God…has certainly in it
more objective reality than those ideas by which finite substances are
represented.
Now it is manifest by the natural light that there must be at least
as much reality in the efficient
and total cause as in its effect; for whence can the effect draw its
reality if not from its cause? And
how could the cause communicate to it this reality unless it possessed
it in itself?"
Whence do these principles draw their indubitability? Even if we grant
that it is contrary to natural
reason that an effect can have greater 'reality' than its cause, that
the concepts of modes and
substances are coherent with Descartes' method, let alone possess the
properties that he ascribes to
them, then surely we can still bring the malign demon into play? Is it
not possible that this all-
powerful demon could bring it about that Descartes has a notion of a
being with all possible
perfections that he calls God? No, says Descartes, because the notion
(representing something perfect)
would then have more objective reality than the demon (as something evil
and thus imperfect) has
formal reality, and 'it is manifest by the natural light' that this is
not possible. But why not? Maybe the
demon has just made it seem impossible, and it seems that Descartes has
no answer to this.
Further problems remain. Cosmological arguments for God invoking the
notion of causation have
always had to contend with the problem of the cause of God. For if all
events (or ideas) are caused
ultimately by God, then what about God Himself? Why should He be exempt
from this rule? The
standard response to this is to claim that God, being omnipotent, causes
Himself. One of the chief
perfections that Descartes attributes to God is that of
'self-existence', that is, that His existence
depends on nothing else but itself. But if we examine this idea, it
seems a little confused. If God is the
efficient cause of God then we are forced to ask how something that does
not yet exist can cause
anything. If God is the formal cause of God, i.e. it is part of the
intrinsic nature of God that he exists -
which seems more likely - then it seems that we have merely a
reformulation of the ontological
argument for God's existence from Meditation 5.
It seems that Descartes may have anticipated the wealth of criticism
that the causal proof of God
would inspire, and so, after explaining how human error and a
benevolent, non-deceiving God are
compatible in Meditation Four, he produced in Meditation Five a version
of the mediaeval
ontological argument for God's existence. Unlike the causal argument,
the ontological argument
doesn't involve the covert import of any new principles. It simply
purports to show that, from an
analysis of his own idea of God, Descartes can show that He necessarily
exists. The reasoning goes
like this:
I have ideas of things which have true and immutable natures.
If I perceive clearly and distinctly that a property belongs to an
idea's true and immutable nature, then
it does actually belong to that nature.
I perceive clearly and distinctly that God's true and immutable nature
is that of a being with all
perfections.
Further, I perceive clearly and distinctly that existence is a
perfection and non-existence a non-
perfection.
Thus existence belongs to God's true and immutable nature.
God exists.
One of the interesting things about this argument is that, at first
sight, it does not seem to depend in
any way upon anything that has been proved hitherto. It is an
application of pure logic, an analysis of
what we mean when we say 'God' and a inference from that analysis.
Descartes explicitly says that an
idea's true and immutable nature does not in any way depend upon his
thinking it, and thus upon his
existence. Once he has perceived clearly and distinctly that an idea's
true and immutable nature
consists in such-and-such, that is the case whether or not he thinks it
is, or even if he exists or not.
Descartes in fact recognises the primacy of the ontological argument:
"although all the conclusions of
the preceding Meditations were false, the existence of God would pass
with me for a truth at least as
certain as I ever judged any truth of mathematics to be." If this is
true, which it seems to be, then this
argument is only as trustworthy as the faculties which enabled us to
construct it, which are the same
faculties that enable us to know mathematical truths, and so it seems
worthwhile to ask how, under
Descartes' theory, we come to know mathematical truths. Descartes claims
we perceive them clearly
and distinctly. How do we know that what we perceive clearly and
distinctly is true? Because God,
being perfect, is no deceiver, and would not let it be the case that we
could ever perceive something
clearly and distinctly without it being the case. It seems then, that
this proof of God, relying on the
veracity of clear and distinct ideas, relies on the certain knowledge
that a non-deceiving God exists.
We have another proof of God, the causal proof as described in
Meditation three. But apart from the
patent futility of using one proof of p to construct another proof of p,
on examining the causal proof of
God further, we find that it, too, relies upon a methodology that can
only be relied upon if the divine
guarantee is present, for if this guarantee is not present, then, as I
mentioned above, how can we be
sure that the all-powerful demon is not exercising his malignant
influence?
This, of course, is the infamous Cartesian circle, first identified by
Arnauld in the Fourth Objections
and discussed ever since. Many philosophers have tried to get Descartes
off the hook in various ways,
some by denying that there is a circle and some by admitting the
circularity but denying its
significance. I will here briefly evaluate a few of their arguments.
Some commentators have taken a passage from Descartes' reply to the
Second set of Objections
(Mersenne's) to indicate that Descartes is only actually interested in
the psychological significance of
fundamental truths. The passage is as follows:
"If a conviction is so firm that that it is impossible for us ever to
have any reason for doubting what
we are convinced of, then there are no further questions for us to ask;
we have everything we could
reasonably want."
Under my interpretation, this is what it is about the cogito that makes
it so important for Descartes,
so we cannot have any argument with the principle expressed by him in
the above passage. But can it
help break the circle? When we clearly and distinctly perceive
something, Descartes says, fairly I
think, that this perception compels our assent, that we cannot but
believe it. God's rôle in the system,
to these commentators, is as a guarantor of our memory regarding clarity
and distinctness. In other
words, once we have proved God's existence, we can happily know that any
memory we have of a
clear and distinct idea regarding x is true i.e. that we really did have
a clear and distinct idea of x. But
this does not seem satisfactory, as we still do not have a divine
guarantee for the reasoning that leads
us from the clear and distinct notions we originally have about God to
the proof of His existence. We
can give assent to the clear and distinct notions we have originally; in
fact, we are compelled to give
this assent when the notions are presented to our mind, but the logical
steps we take from these ideas
to the final proof is still subject to the evil demon because God is not
yet proven. Furthermore, because
these steps are needed, the memory of the original clear and distinct
ideas are themselves subject to
doubt because God is not yet proven. It seems that the only way either
of the proofs of God could be
accepted would be if we had an original clear and distinct perception of
God directly presented to our
mind (qualitatively similar to the cogito). But this in itself would
make any future proofs redundant.
Interestingly, this sounds quite similar to a divine revelation.
Harry Frankfurt, in his book 'Demons, Dreamers and Madmen', has argued
that what Descartes is
actually looking for is a coherent, indubitable set of beliefs about the
universe. Whether they are 'true'
or not is irrelevant. Perfect certainty is totally compatible with
absolute falsity. Our certainty may not
coincide precisely with 'God's' truth, but should this matter?:
"Reason…can give us certainty. It can serve to establish beliefs in
which there is no risk of betrayal.
This certainty is all we need and all we demand. Perhaps our certainties
do not coincide with God's
truth…But this divine or absolute truth, since it is outside the range
of our faculties and cannot
undermine our certainties, need be of no concern to us." (Frankfurt, p
184)
This is almost a Kantian approach to knowledge, where we as humans only
concern ourselves with
the phenomena of objects as they present themselves to us, not with the
objects in themselves. Can we
ascribe this view to Descartes? It's tempting, given what we have said
above regarding the prime
importance of indubitability, but it would seem that a God presenting
ideas to us in a form which
doesn't correspond to reality, and then giving us a strong disposition
to believe that they do
correspond to reality would be a deceiving God and contrary to
Descartes' notion of Him. Thus the
belief set would not be coherent. Perhaps, as we do not have clear and
distinct ideas of the bodies we
perceive, and as the divine guarantee only extends as far as clear and
distinct ideas, we are being too
hasty in judging that reality is how it appears to be and if we stopped
to meditate further we would see
that reality is actually like something else. But aside from the fact
that this seems unlikely, Descartes
never seemed to envisage the possibility.
So much for the Cartesian circle. Where does this leave the ontological
argument, which we had only
just begun to discuss? Aside from the methodological difficulties, there
do seem to two further
problems with it. The first has been noted by almost every student of
Descartes over the years - that of
the description of existence as a property. Put briefly, this objection
states that existence is not a
property like 'red' or 'hairy' or 'three-sided' that can be applied to a
subject, and thus it makes no sense
to say that existence is part of something's essence. If we assert that
x is y, we are already asserting the
existence of x as soon as we mention it, prior to any application of a
predicate. from the beginning. In
other words, to say 'x exists' is to utter a tautology and to say that
'x doesn't exist' is to contradict
oneself. So how can sentences of the form 'x doesn't exist' make sense?
one may well ask. It is because
these sentences are shorthand for 'the idea I have of x has no
corresponding reality' and it was to
solve problems like this that Bertrand Russell constructed his theory of
descriptions. To add existence
to an idea doesn't just make it an idea with a new property, it changes
it from an idea into an existent
entity.
Finally, if Descartes is right, there seems no reason why we cannot
construct any other idea whose
essence includes existence. For instance, if I conjure up the idea of
'an existent purple building that
resembles the Taj Mahal', then it is the true and immutable nature of
this idea that it is a building,
that this building resembles the Taj Mahal, that the building is
purple, and that it exists. But no such
building does exist, as far as I am aware, and if it did exist, its
existence would not be necessary, but
contingent. This in itself is enough, I think, to show that the
ontological argument is false.
Once we have destroyed Descartes' proofs of the existence of God, the
edifice of knowledge
necessarily comes tumbling down with them, as we find that almost
everything Descartes believes in
is dependent on God's nature as a non-deceiver:
"I remark…that the certitude of all other truths is so absolutely
dependent on it, that without this
knowledge it is impossible ever to know anything perfectly." (p.115)
The only possible exceptions are those assent-compelling beliefs such
as the cogito. Even these,
however, are doubtful when we are not thinking about them, and the above
passage does give weight
to Edwin Curley's argument that:
"Descartes would hold that the proposition "I exist" is fully certain
only if the rest of the argument of
the Meditations goes through. We must buy all or nothing."
This is not the end of the story, though. As far as Descartes is
concerned, by the end of Meditation
Five, he has produced two powerful proofs of God, has a clear and
distinct notion of his own self, has
a criterion for truth, knows how to avoid error and is beginning to form
ideas regarding our
knowledge of corporeal bodies.. And so it remains only to explain why we
are fully justified in
believing in corporeal bodies, and also to draw the ideas of Meditation
Two regarding self-knowledge
to their full conclusion.
Regarding the nature of corporeal bodies and our knowledge of them, it
seems to me that, given his
premises, the conclusions Descartes draws in Meditation Six are
generally the correct ones. He again
invokes the causal to argue that the ideas of bodies we have within our
minds must be caused by
something with at least as much formal reality as the ideas have
objective reality. We could
theoretically be producing these ideas, but Descartes dismisses this
possibility for two reasons - firstly,
that the idea of corporeality does not presuppose thought and secondly
that our will seems to have no
effect on what we perceive or don't perceive. (This second argument
seems to me to ignore dreaming,
in which what we perceive derives from us but is independent of our
will). The ideas, then, could
come from God, or from another being superior to us but inferior to God.
But this, too, is impossible,
argues Descartes, as if it were the case that God produces the ideas of
bodies in us, then the very
strong inclination we have towards believing that the idea-producing
bodies resemble the ideas we
have would be false and thus God would be allowing us to be deceived
which is not permissible. The
same would apply if any other being were producing these ideas. Thus,
concludes Descartes, it is most
likely that our ideas of corporeal bodies are actually caused by bodies
resembling those ideas. We
cannot be certain, however, as we cannot claim to have clear and
distinct notions of everything we
perceive. We can, however, claim certainty with regard to those
properties of bodies which we do
know with clarity and distinction; namely, size, figure (shape),
position, motion, substance, duration
and number (not all of these assertions are justified). Obviously we
cannot claim that we know these
properties for specific bodies with clarity and distinction, for to do
so would leave open the question of
why it is that astronomy and the senses attribute different sizes to
stars. What Descartes means is that
we can be sure that these primary qualities exist in bodies in the same
way that they do in our ideas of
bodies. This cannot be claimed for qualities such as heat, colour, taste
and smell, of which our ideas
are so confused and vague that we must always reserve judgement. (This
conclusion is actually quite
similar to the one John Locke drew fifty years later in his Essay
Concerning Human Understanding.)
I think we can grant this reasoning, with the caveat regarding dreaming
that I noted above, and of
course the other unproved reasonings that Descartes exhumes here, such
as the causal principle.
Furthermore, it seems to be further proof that Descartes does believe we
can get to know objects in
themselves to a certain extent.
Finally, I turn to Descartes' argument for the distinction of mind and
body. Descartes believes he has
shown the mind to be better known than the body in Meditation Two. In
Meditation Six he goes on to
claim that, as he knows his mind and knows clearly and distinctly that
its essence consists purely of
thought, and that bodies' essences consist purely of extension, that he
can conceive of his mind and
body as existing separately. By the power of God, anything that can be
clearly and distinctly conceived
of as existing separately from something else can be created as existing
separately. At this point,
Descartes makes the apparent logical leap to claiming that the mind and
body have been created
separately, without justification. Most commentators agree that this is
not justified, and further, that
just because I can conceive of my mind existing independently of my body
it does not necessarily
follow that it does so. In defence of Descartes, Saul Kripke has
suggested that Descartes may have
anticipated a modern strand of modal logic that holds that if x=y, then
L (x=y). In other words, if x is
identical to y then it is necessarily identical to it. From this it
follows that if it is logically possible that
x and y have different properties then they are distinct. In this
instance, that means that because I can
clearly and distinctly conceive of my mind and body as existing
separately, then they are distinct. The
argument, like much modern work on identity, is too technical and
involved to explore here in much
depth. But suffice to say that we can clearly and distinctly conceive of
Dr Jekyll and Mr. Hyde as
being distinct and yet they are identical, necessarily so under Kripke's
theory. It is doubtful that
Kripke can come to Descartes' aid here and Descartes needs further
argument to prove that the mind
and the body are distinct.
And so we finish our discussion of Descartes' attempts to extricate
himself from the sceptical doubts
he has set up for himself. As mentioned previously, the ultimate
conclusion to draw regarding the
success of the enterprise that Descartes set for himself must be that he
failed. When the whole
epistemological structure is so heavily dependent on one piece of
knowledge - in this case the
knowledge that God exists - then a denial of that knowledge destroys the
whole structure. All that we
can really grant Descartes - and this is certainly contentious - is that
he can rightly claim that when a
clear and distinct idea presents itself to his mind, he cannot but give
his assent to this idea, and
furthermore, that while this assent is being granted, the clear and
distinct idea can be justly used as a
foundation for knowledge. The most this gets us - and this is not a
little - is the knowledge of our own
existence each time we assert it. But Descartes' project should not be
judged by us as a failure - the
fact that he addressed topics of great and lasting interest, and
provided us with a method we can both
understand and utilise fruitfully, speaks for itself.
Bibliography
1. Descartes, René A Discourse on Method, Meditations and Principles of
Philosophy
trans. John Veitch. The Everyman's Library, 1995.
Descartes, René The Philosophical Writings of Descartes volume I and II
ed. and trans. John
Cottingham, R. Stoothoff and D. Murdoch. Cambridge, 1985.
Frankfurt, Harry Demons, Dreamers and Madmen. Bobbs-Merrill, 1970.
Curley, Edwin Descartes Against the Skeptics. Oxford, 1978.
Vesey, Godfrey Descartes: Father of Modern Philosophy. Open University
Press, 1971.
Sorrell, Tom Descartes: Reason and Experience. Open University Press,
1982.
The Oxford Companion to Philosophy ed. Ted Honderich. Oxford University
Press, 1985.
Cottingham, John Descartes. Oxford, 1986.
Williams, Bernard Descartes: The Project of Pure Enquiry. Harmondsworth,
1978.
Russell, Bertrand The History of Western Philosophy. George Allen and
Unwin, 1961.
11. Kripke, Saul Naming and Necessity. Oxford 1980.
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