Prolegomena to Any Future Metaphysics

Contents

1. Introduction 21 min 11

   Kant’s preface explains that the Prolegomena is written for future teachers of metaphysics, not for pupils or historians of philosophy. He asks whether metaphysics is possible at all, since it has made no progress while other sciences advance. Hume’s attack on the concept of cause, misunderstood by Reid, Oswald, Beattie and Priestley, first interrupted Kant’s “dogmatic slumber”. Generalising Hume’s problem led to the Critique of Pure Reason. Kant admits that the Critique is obscure and long-winded, and offers this analytical sketch as a remedy, while insisting that anyone who would judge metaphysics must accept or refute his solution.

2. Preamble on the Peculiarities of All Metaphysical Cognition 36 min 9

   The Preamble defines metaphysical knowledge as a priori and distinguishes analytic judgments, which only unpack a concept, from synthetic ones, which extend it. Mathematical judgments such as 7 + 5 = 12 are synthetic, a point Kant says Hume missed. Metaphysics proper consists of synthetic a priori judgments. Since no metaphysics yet exists as a science, Kant proceeds analytically from mathematics and pure physics, which do exist. He asks “How are synthetic propositions a priori possible?” and divides the inquiry into four questions about mathematics, natural science, metaphysics as a natural disposition, and metaphysics as a science.

3. I How Is Pure Mathematics Possible? 35 min 7

   Part I asks how pure mathematics is possible. Mathematics must construct its concepts in intuition, and it can do so a priori only if space and time are forms of our sensibility rather than properties of things in themselves. Geometry rests on space and arithmetic on time. The paradox of incongruent counterparts, such as left and right hands, supports this view. Three Remarks follow. Geometry is valid of all objects of sense because they are appearances. This position is not idealism, since bodies exist and only what they are in themselves is unknown. And it does not turn the world into illusion. Kant renames his view “critical idealism”.

4. II How Is the Science of Nature Possible? 1 h 13 min 28

   Part II asks how pure natural science is possible. Nature, as the lawful whole of objects of experience, can be known a priori only through the conditions of experience itself. Judgments of perception, valid only for me, become judgments of experience, valid for everyone, when perceptions are brought under pure concepts of the understanding. Kant presents the tables of judgments, categories and principles, then answers Hume: causality is objectively valid, but only for experience. The categories have no meaning beyond it. The understanding prescribes its laws to nature. An appendix defends the system of categories against Aristotle’s unprincipled list.

5. III How Is Metaphysics in General Possible? 52 min 19

   Part III asks how metaphysics is possible as a natural disposition. Reason, seeking the unconditioned, forms ideas whose objects cannot be given in experience. These are the soul (psychological idea), the world (cosmological idea) and God (theological idea), derived from the three forms of syllogism. The soul cannot be proved permanent beyond life. The four antinomies set equally proven theses against antitheses. The first two are resolved as both false, the last two as possibly both true, allowing freedom alongside natural necessity. The ideas are valid only as regulative principles of systematic unity, not as knowledge of objects.

6. Conclusion: On the Determination of the Bounds of Pure Reason 35 min 8

   The conclusion determines the boundary of pure reason. Knowledge reaches only to possible experience, yet reason cannot help thinking of things in themselves. Kant distinguishes bounds, which touch something beyond, from mere limits. He answers Hume’s attack on theism with a “symbolical anthropomorphism”: we may think the world as if it were the work of a supreme reason, by analogy, without claiming to know that being. The ideas protect against materialism, naturalism and fatalism and make room for morality. This completes the answer to how metaphysics is possible as a natural disposition.

7. Solution of the General Question of the Prolegomena: How Is Metaphysics Possible as a Science? 17 min 2

   Kant answers his last question: metaphysics can become a science only through a complete critique of reason, which stands to the old school metaphysics as chemistry to alchemy. Dogmatic metaphysics is in decay, and the indifference this produces is the best moment for reform. Human beings will never give up metaphysics. Kant challenges anyone to prove a single synthetic a priori metaphysical proposition dogmatically. He rejects appeals to probability and to common sense, which can judge rules only in concrete cases, never a priori.

8. Appendix: On What Can Be Done to Make Metaphysics Actual as a Science 29 min 8

   The Appendix answers the anonymous Göttingen review of January 1782, which called the Critique a system of “higher idealism”. Kant contrasts genuine idealism, for which only the ideas of reason are true, with his own principle that truth lies only in experience. He renames his view “critical” idealism, to distinguish it from Berkeley’s and Descartes’s. He challenges the reviewer to defend any one of the antinomies’ eight propositions. He proposes that the Critique be examined piece by piece, using the Prolegomena as an outline, and argues that critique benefits theology and drives out mysticism.