Making Connections, from Descartes to Kant

Because you all have read Descartes’ Meditations on First Philosophy, it seemed to me that this might be a good place to begin making connections with Kant’s Critique of Pure Reason. I have listed four different points of intersection between Descartes and Kant in what follows. 

Both think:
(1) there is some doubt about the relation between representations and the objects they represent. This is for Descartes the principal reason that we cannot trust our knowledge through the senses. Although Kant does not thematize this issue, it is implied in the basic transcendental framework: if we can’t know the object except through its appearances, there must be some doubt about the relation of our representations to it.

(2) that “extension” and the principles of mathematics (including space and time) are something known “innately” by the mind. Descartes explains in his fifth Meditation that these are the characteristics of sensuous objects that we can always know clearly and distinctly, precisely because they are features that are known by reason and (although Descartes never says as such) synthesized in the judgment of the sensuous thing. Kant thinks that space and time are effects of our pure form of intuition. That is, we may only have experience through these forms of space and time. The difference is, that Descartes thinks these characteristics must actually belong to the things in the world, the example of this being the infinite, which is known by reason but must equally, according to Descartes, be attributable to an infinite being which is the cause of the idea of the infinite.

(3) that the idea of causality is an “innate” idea. Descartes does insofar as he assumes this for his cosmological proof. The objective reality of an idea must have a cause of equal or less formal reality (but not more than, note!). Without this idea, Descartes can’t get past the fragile certainty of the “cogito ergo sum”. Kant also thinks we have a concept, as he will call it, of causality, which is used to synthesize experience, and which is drawn from the purely logical use of the understanding. But he will not extend the usage of this concept beyond experience, whereas for Descartes, it’s essential if he wants to prove the existence of God (clearly something beyond experience).

(4) that the thinking subject is the starting place of our removal from skepticism. For Descartes, it is the “cogito ergo sum” that removes us from the abyss of unknowing. For Kant, it is the “critique” of this faculty that allows us to know what we can know. However, it will always be somewhat strange that Descartes is ready to make the Copernican turn, as Kant actually does, and yet immediately falls back into the hands of the Scholastic tradition and the proof for the existence of God. Despite our disappointment with Descartes’ results, we must remember that for him it will always be primarily an epistemological rather than metaphysical inquiry. This is a vital movement, anticipating Kant’s.