An Imperfect Circle

March 5, 2004
 

In 1641, René Descartes’ Meditations on First Philosophy was published.  In it, Descartes set out to prove the existence of God, and he subsequently used that proof as the basis for his argument that sense perception reflects reality.  In response, Antoine Arnauld posited that Descartes’ proof of God’s existence is invalid because it is a circular argument.  These are their stories.

Descartes’ argument for the existence of God is a conundrum.  Descartes’ proof that God exists is a sort of convoluted Anselm-esque ontological argument.  Antoine Arnauld disputes the argument because according to him, Descartes is saying that clear and distinct perception is the basis for and product of God’s existence.  The clear and distinct qualifier is important.  If, for example, a person were to approach me with news about Ted the Emancipator of Altoria IV, I would have no idea what the person was talking about.  My knowledge of Ted the Emancipator is limited only to the fact that he Emancipated Altoria IV, whatever that is, and that his name is Ted.  My idea of Ted is fuzzy and muddled, and I would need someone to clarify Ted’s story if I were to have any idea of him other than his name.  Descartes believed he had a clear and distinct idea of God, and while this may be true, it is unimportant to the validity of his argument, which is as follows:

1.      When I can have a clear and distinct idea of something, it is based on something I have sensed or of which I have prior knowledge.

2.      I have a clear and distinct idea of God (i.e. a perfect being).

3.      If I have a clear and distinct idea of God, I must have sensed his existence somehow, or I must have prior knowledge of his existence.

4.      Therefore, God must exist. 

Descartes basically says that he has a clear and distinct idea of God, and that because of the nature of ideas (that they must be caused by something), God must exist.  In other words, God caused the idea of God in Descartes’ mind.  He goes on to say that since God exists as a real entity, and since God is perfect, everything God tells him is real must be true.  Therefore, if he has a clear and distinct idea of something, it must be caused by something real.  For example, I have an idea of a toothbrush because I have seen and used toothbrushes.  I also have an idea of Wookiees, even though they do not really exist.  The idea of them is based on what I have seen in film and read in books.  In other words, I have prior knowledge of them.  When someone tells me about Wookiees, toothbrushes, or Wookiees brushing their teeth, I have a clear and distinct idea of what that person is describing.  A perfect being would not lie to me about Wookiees or my toothbrush.  As such, Descartes reasons that a perfect being would not lie to him about the clear and distinct fire in his room or the lump of wax in his hand.  Therefore, the clear and distinct world he perceives must be real.

Upon reading Descartes’ argument for the existence of God, Antoine Arnauld declares the argument circular.  He reasons that Descartes’ argument states that we can only know things to be true if we can clearly and distinctly perceive them as true as a result of God’s existence, and that we only know of God’s existence through clear and distinct perception.  To put it another way, according to Arnauld, Descartes said that clear and distinct ideas proved God to be real, and God proved clear and distinct ideas to be real.  On the surface, Arnauld’s criticism seems valid, but upon closer investigation, it becomes clear that the problem goes much deeper. 

As it stands, it seems Arnauld is saying Descartes’ argument is invalid because used the same phrase in both proofs.  While that may be the case, it is meaningless.  Arnauld seems to be arguing semantics over ideas.  The argument as Arnauld sees it is this:  All clear and distinct ideas are true because God says so.  God is real because of the clear and distinct idea.  In other words, God is real because God says so.  That is but one way of looking at the argument.  Descartes’ meaning was different.  He clarified it in his rebuttal to Arnauld:

[I]t is manifest to us that God exists, since we are attending to the arguments that prove this; but later on, it is enough for us to recall our having clearly perceived something in order for it to be true.  This would not suffice, unless we knew that God exists and does not deceive us. 

Ultimately, Descartes is asserting that all clear and distinct ideas are true because God says they are.  God exists because a clear and distinct idea of him exists.  However, the clear and distinct idea that God exists is only affirmed, not proven, by the statement that God is no deceiver.  The proof that God actually exists lies in the premise that all ideas have a source.  This is the part of the argument that Arnauld fails to grasp.  When looking deeper, for the purposes of being thorough, one must consider what caused Descartes’ idea of God. 

Descartes says he knows that God exists.  His reasoning is that his idea must be based on something, and that thing is not something planted in his mind by an evil genius, nor is it based on something he imagined.  It must be based on something real.  In essence, Descartes says that God exists because God gave man the capacity to have an idea of him.  The idea was placed there by God, according to Descartes.  It is at this point in the argument that the circularity begins.  Proof of God’s existence relies on presupposition of his existence.  Ultimately, Descartes is saying what Arnauld thinks he is saying; that God exists because God says so. 

Arnauld’s criticism is accurate but misplaced.  He says that Descartes’ argument is circular because, ultimately, it says that God exists because God says so.  While the criticism is accurate, Arnauld fails to take into account Descartes’ actual, deeper, argument; instead dwelling on the superficial argument surrounding the phrase clear and distinct.  While Arnauld’s criticism may be a good starting point for arguing against Descartes’ proof, it is not sufficiently thorough.  Arnauld’s criticism is based more on the language Descartes used in his argument than on the ideas he was trying to convey.  While he was right that the argument was circular, he was unaware of how big the circle was.