Tightening up Descartes’s Theistic Argument

Descartes’s theistic argument suffers from being written in Scholastic-ese and from being less tied to the doctrine of the Meditations than it could be. Here’s a simplified but tighter version:

1.) Causes cannot be less real than effects.

Take this as an axiom. One instance of the axiom would be that if an effect is real its cause is too, or that a real effect cannot have an unreal cause.* The word real would draw the attention, but I think Descartes can give a very good answer to what this is:

2.) The real is proportionate to its truth. 

The real is the true and certain, and things are less true and certain to the extent they can be doubted. Given Mediation I and II, this gives us an order of reality with the sensible at the bottom, the mathematical one step up, the self a step above this. Taken formally, the grades of reality are:

a.) Things that cannot think themselves (the physical or sensible or res extensa)

b.) Things that cannot think themselves, but exist by being thought (mathematical things)**

c.) Things that can think themselves, but are contingently thinking themselves (my self, human res cogitans)

d.) Things that can think themselves, and necessarily think themselves eternally (an Aristotelian thought-thinking itself, or divinity, or what Descartes just calls an eternal being.)

It is important that these grades of reality belongs to things both in the order of knowledge and reality, since they are more and less true both as ideas and as things (if they exist)

3.) Ideas are effects. 

One can take this either as an axiom or as a corollary to the cogito in Med. II. Since the cognate shows this is true of ideas as such, the axiom is equivalent to “Ideas are (ultimately) effects of something not merely an idea”.

4.) I have an idea of God, an absolute being greater than myself. 

The first part is probably given by anyone. Descartes needs our idea of God to be not sheerly negative, but an analogous grasp of God could do the trick since analogous names are explicitly opposed to simply negative ones. That said, one’s theory of analogy or extrapolation or abstraction of traits would be a significant point of contention in the argument Descartes is giving.

5.) Therefore, God exists.

If not, a (d) grade effect arises from a sub-(d) cause.

*Notice that by making the opening move about causes it is difficult to characterize the argument as an ontological argument.

**While this is not Descartes’s theory of mathematical reality but the Thomistic one, it helps to explain the role that the mathematical plays in his philosophy.

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