In a previous post I outlined Descartes’ view that the eternal truths depend on God’s will and raised some questions about the metaphysics involved. In this post I want to raise some epistemological questions: On what grounds does Descartes take himself to be entitled to hold that his account of the divine will is correct? Why doesn’t Descartes instead adopt a principled agnosticism about the eternal truths? According to such an agnostic view we shouldn’t affirm that God couldn’t have made it false that contradictories cannot be true together, for instance. However, neither should we affirm that God could have done so.
In his letter to Mersenne on the 15th April, 1630, Descartes claims for the first time that the mathematical truths have been laid down by God and depend on him entirely (CSMK, 23). He advises Mersenne to “not hesitate to assert and proclaim everywhere” that this is so. At first glance it appears that Descartes is supremely confident that his view is correct. However, in the next paragraph it becomes clear that his motivation is to subject the view to criticism (emphasis added):
I hope to put this in writing … but I do not want you to keep it secret. On the contrary I beg you to tell people as often as the occasion demands, provided you do not mention my name. I should be glad to know the objections which can be made against this view; and I want people to get used to speaking of God in a manner worthier, I think, than the common and almost universal way of imagining him as a finite being.
Moreover, in response to the objection that God could then change the mathematical truths since God’s will is free, the principle that Descartes gives in support of his position is one that yields no more than what we have called “principled agnosticism”. Descartes writes that “In general we can assert that God can do everything that is within our grasp but not that he cannot do what is beyond our grasp”. On the 27th May, 1630, Descartes clarifies to Mersenne that he doesn’t grasp that God is the author of the eternal truths (CSMK, 25). Nevertheless he claims to know that the eternal truths are authored by God:
I know that God is the author of everything and that these [eternal] truths are something and consequently that he is their author. I say that I know this, not that I conceive it or grasp it … To grasp something is to embrace it in one’s thought; to know something, it is sufficient to touch it with one’s thought.
Eight years later, in 1638, just three years before the Meditations were published, Descartes again takes up this issue with Mersenne (27th May; CSMK, 103). In this letter he insists that his view about the eternal truths does not deal with a question that is “beyond the capacity of the human mind” but rather one that is “merely beyond the capacity of our imagination”, so that “our intellect can reach the truth of the matter”.
In the Sixth Set of Replies of the Meditations (CSM II, 294) Descartes writes:
Again, there is no need to ask how God could have brought it about from eternity that it was not true that twice four make eight, and so on; for I admit this is unintelligible to us. Yet on the other hand I do understand, quite correctly, that there cannot be any class of entity that does not depend on God … it would be irrational for us to doubt what we do understand correctly just because there is something which we do not understand and which, so far as we can see, there is no reason why we should understand.
I agree with Descartes that if God could have brought it about that it not be the case that contradictories cannot be true together, and so forth, then we should not expect to understand how God could have done this. However I see no argument in Descartes for how we know that God could have done so.
Later, in his letter dating to 2 May, 1644 (CSMK, 235), which we read for class, Descartes appears to add an important hedge when outlining his position (emphasis added):
The first consideration shows us that God cannot have been determined to make it true that contradictories cannot be true together, and therefore that he could have done the opposite. The second consideration assures us that even if this be true, we should not try to comprehend it, since our nature is incapable of doing so.
The “first consideration” is that “The power of God cannot have any limits”, and seems to me to simply beg the question at hand. Is the subsequent phrase “even if this be true” evidence that Descartes did, in the end, adopt an agnostic position?