Work · Kant
Critique of Pure Reason
1781 · A vast architecture
What can the mind know? The book that says the mind shapes experience rather than copying it.
1781
First edition
1787
Second edition
Synthetic a priori
The question
The two worlds the book draws a line between
Kant’s "Copernican revolution" is the claim that objects conform to our way of knowing, not the reverse. The price is a permanent fence: we know the world only as it appears to minds built like ours, never as it is in itself. Everything the book builds, and everything German Idealism later tore down, sits on that line.
The shape of the argument
Introduction
The driving question: how are synthetic a priori judgments (informative truths known in advance of all experience, like "7 + 5 = 12") possible at all?
Transcendental Aesthetic
Space and time are not things out in the world but the mind’s own forms of intuition, which is why geometry can be both certain and about the world.
Transcendental Analytic
The categories of the understanding (causality, substance) are the a priori scaffolding every experience must fit; and the line is drawn between phenomena and the unknowable thing-in-itself.
Transcendental Dialectic
The illusions reason falls into when it oversteps experience: the antinomies, the paralogisms of the soul, and the demolition of the classic proofs of God.
Doctrine of Method
What is left for metaphysics once criticism has done its work: not a science of the beyond, but a disciplined account of reason’s own limits.
The cast
Kant — spends a silent decade, then publishes the book that resets philosophy, at fifty-seven
Hume — the spark: his attack on causation "woke Kant from his dogmatic slumber"
The thing-in-itself — the unknowable reality behind appearances, and the most argued-over move in the book
The German Idealists — Fichte, Schelling, Hegel, who took the thing-in-itself as the thread to pull
The famous bits
The Copernican revolutionPreface (2nd ed.)
Stop assuming the mind conforms to objects; assume objects conform to the mind, and metaphysics becomes possible.
The synthetic a prioriIntroduction
Some truths are both informative and known in advance of experience; explaining how is the whole task.
Space and time as forms of intuitionTranscendental Aesthetic
Space and time are not out there to be found; they are the lenses every experience is already wearing.
The categories and causalityTranscendental Analytic
Cause and effect is not read off the world but supplied by the understanding as a condition of experience.
Phenomena and the thing-in-itselfTranscendental Analytic
We know appearances, shaped by us; the thing as it is in itself is thought but never known.
Existence is not a predicateTranscendental Dialectic
The ontological proof of God fails because "exists" adds nothing to the concept of a thing.