Rationalism

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Descartes' method in the Meditations is not ordinary doubt, the sort that questions a particular claim because of a particular reason to distrust it. It is a deliberate, total doubt, applied to every belief he holds, including the ones that seem most obviously secure, on the ground that if even one of his beliefs might be false and he cannot yet tell which, none of them can serve as a foundation until sorted. The senses fail sometimes, so anything resting on the senses goes. Perhaps he is dreaming right now and only seems to be seated by a fire holding paper, so even the vivid conviction of waking experience goes. He pushes further still, imagining a deceiver of unlimited power bent on making even two plus three seem to equal five when it does not, so that even mathematics, which had seemed doubt proof, goes as well. What is left, after every possible ground for doubt has been applied, is a single point that survives the very act of doubting it: whatever else might be false, the doubting itself is happening, and something must be doing the doubting. I think, therefore I am is not a conclusion reached by inference from other premises, on Descartes' own account, but something closer to an immediate recognition, true the instant it is entertained, because entertaining it already proves a thinker exists to entertain it. From that one certain point, Descartes tries to rebuild everything else, God's existence, the reliability of clear and distinct ideas, the external world, by reason alone. Whether the rebuilding succeeds is a separate question from whether the doubt was total enough to need it; but the method, doubt everything until you strike something doubt itself cannot touch, is the founding gesture of Rationalism as a program, not merely one philosopher's peculiar exercise.

This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.

Descartes needed two substances, extended body and thinking mind, and spent real effort explaining how they interact without ever fully closing the gap. Spinoza's answer, a generation later, was to deny there are two substances to begin with, or even a plurality of finite substances at all. On Spinoza's system there is exactly one substance, which he calls God or Nature interchangeably, infinite, self caused, and expressed under infinitely many attributes, of which thought and extension are simply the two human beings happen to be able to perceive. A mind and its body, on this view, are not two interacting things but one and the same mode of the single substance, considered under two different attributes; the puzzle of how a mental event causes a physical one dissolves rather than getting solved, because there were never two separate things to connect in the first place. This is Rationalism pushed to its most demanding conclusion: not merely that reason can establish some truths independently of the senses, which Descartes had already argued, but that the entire structure of reality can in principle be derived geometrically, proposition by proposition, the way Euclid derives theorems from axioms, which is exactly the form Spinoza gave his own masterwork. Where Descartes left interaction as an acknowledged loose end, Spinoza's single substance has no loose end to explain, at the cost of a metaphysics far stranger and, to many of his contemporaries, far more alarming than anything in the Meditations. Reason, followed all the way, does not always arrive somewhere comfortable.