Abstract

Descartes' conception of facultive inference is of a simple, primitive, unanalyzable, unmediated, unjustifiable "mental operation by which one grasps connections between one's ideas," in contrast to Aristotle's discursive inference consisting in "spelling out and analyzing its steps". Gaukroger shows why Descartes takes Aristotelian syllogistic to be merely presentative of material already known, and thus takes deduction to be only a way of ordering and displaying this knowledge. For Descartes, only synthesis leads to new knowledge. Thus it is a mistake to give an "apriorist and deductivist interpretation of Descartes's method... whereby all scientific knowledge is... deduced from the cogito". One "problem with a purely deductive approach... is... that... first principles take us to every possible world". To settle which account is of the actual world, we must resort to experiment. Also leading to a nondeductive method in science is Descartes' doctrine of God's creation of truths which means that "human knowledge can no longer be modeled in any way on divine knowledge". Descartes' three-part problem-solving method, then, is to pose the problem in quantitative terms, test the solutions experimentally, and incorporate the solution into his system of natural philosophy.