Editing Immanuel Kant (section)

=== Synthetic A-Priori ===
Prior to Kant, the pairs analytic-a-priori and synthetic-a-posteriori were taken as coextensive, particularly by Hume, who argued on this basis that all logical connection was (because synthetic) derived from experience (a posteriori). Famously he gave the example of billiard balls, and argued that even when we see one hit another and the the latter moves, we cannot derive cause and effect with any '''necessity''' because this assertion is based on a mere repetition of contingent experience; this leads ultimately to a a profound and convincing skepticism, tending towards a nihilistic sort of anthropology in which everything that makes us human is beat into us by the caprice of experience. Kant and Herder read Hume in the 1760s, and while the student pushed onward in this brave new world and became the father of modern anthropology and social science, the master withdrew, and began formulating a defense. It took him almost 20 years.

So the problem of '''pure reason''' is this: ''how can any reason be possible which is not reducible to experience, or itself reduced to the bare form of non-contradiction?'' Kant's answer is the '''synthetic a priori''', which he arrives at by subverting the traditional divide between analytic-a-priori and synthetic-a-posteriori. He takes mathematics hostage, demonstrating in the introduction to the first critique that geometrical proofs and arithmetic sums are not analytic as supposed (do you really have the sum of 172128 + 8492817 contained in the concept of these numbers?), that they are synthetic, and since math is obviously not derived from experience. Kant has won a beachhead, from which he promptly deploys his forces, seizing first space and time in the '''Transcendental Aesthetic''' and later the categories in the '''Transcendental Logic.''' With this, metaphysics was (for the time being) saved.