Critique of Practical Reason

Contents

1. Preface 22 min 17

   Kant explains why the book criticises practical reason in general rather than pure practical reason: if pure reason is shown to be practical by fact, it needs no critique. Freedom, proved real by the moral law, becomes the keystone of the system, and God and immortality are assumed as conditions of the highest good. He defends the double view of the self as phenomenon and noumenon, answers critics of the Groundwork, and defends his terminology. He closes by arguing that a universal empiricism like Hume’s, which puts custom in place of necessity, would end in a scepticism that swallows mathematics too.

2. Introduction: Of the Idea of a Critique of Practical Reason 4 min 2

   A short statement of the problem. The first Critique restrained pure reason when it strayed beyond experience; here the question is whether pure reason alone can determine the will. If it can, the critique must restrain empirically conditioned reason, which claims to be the will’s only guide. Kant then sets out the plan: Elements (an Analytic and a Dialectic) and a Methodology, with the Analytic running from principles to concepts to the senses, the reverse of the first Critique’s order.

3. I.1.1 Analytic, Chapter I: Of the Principles of Pure Practical Reason 1 h 1 min 19

   The core of the book. Kant distinguishes maxims from laws and hypothetical from categorical imperatives, then argues that every principle based on a desired object rests on self-love and cannot be a law. Only the form of universal legislation can determine a free will, and the moral law and freedom imply each other; we know freedom through the law. He states the fundamental law, calls our consciousness of it a “fact of reason”, and defines autonomy. Examples (the deposit, false witness, the gallows, the steward) and a table of rival heteronomous ethics complete the case.

4. I.1.1 Of the Deduction of the Fundamental Principles of Pure Practical Reason 41 min 9

   Kant explains why the moral law, unlike the categories, cannot be deduced: it is a fact of pure reason, certain of itself. Instead it serves as the ground of a deduction of freedom, giving objective, though only practical, reality to the idea speculation could only think. The law gives the sensible world the form of a supersensible nature. A second section recalls Hume’s attack on causality and Kant’s answer to it, and argues that the pure origin of the concept of cause allows its practical use for a free will as a cause outside nature.

5. I.1.2 Analytic, Chapter II: Of the Concept of an Object of Pure Practical Reason 36 min 14

   The only objects of practical reason are good and evil, which concern the will and its maxims, not our weal and woe; the Stoic in pain was right that pain is no evil. Kant explains the “paradox of method”: good and evil must be defined after the moral law and by means of it, the mistake of all earlier ethics being to begin with the good. A table of categories of freedom follows. The typic then lets the form of a law of nature stand in for the moral law in judging cases, guarding against both empiricism and mysticism.

6. I.1.3 Analytic, Chapter III: Of the Motives of Pure Practical Reason 46 min 15

   How the moral law becomes a motive. By striking down self-conceit it produces humiliation and, positively, respect, the one feeling caused by reason and the only moral motive. Respect is owed to persons for the law their example shows. Kant separates acting according to duty from acting from duty, interprets the command to love God and neighbour as practical love, and warns against moral fanaticism. In his apostrophe to Duty he finds its root in personality, freedom from nature’s mechanism, which makes every rational being an end in himself.

7. I.1 Critical Examination of the Analytic of Pure Practical Reason 47 min 14

   Kant explains why the Analytic of practical reason runs in the reverse order to the first Critique, from principles to concepts to feeling. He separates the doctrine of happiness from morality, as a chemist separates elements by experiment, and calls compatibilist “comparative freedom” a wretched subterfuge that leaves a person no freer than a turnspit. Freedom is saved only by the ideality of time: as appearances our acts are caused, but as things in themselves we author our whole character. That is why conscience and remorse are justified. Freedom alone among the ideas of reason gains practical reality, through the moral law.

8. I.2.1 Dialectic, Chapter I: Of a Dialectic of Pure Practical Reason Generally 8 min 3

   Book II opens. Pure reason, practical as well as speculative, demands the unconditioned and so falls into illusion. Its practical form is the search for the unconditioned totality of the object of the will, the highest good (summum bonum). Kant recalls the ancient sense of philosophy as a doctrine of the highest good and a discipline of wisdom. He insists that the highest good, though the whole object of a pure will, must never be its determining ground, or morality would become heteronomy; only the moral law, contained within it, determines the will.

9. I.2.2 Dialectic, Chapter II: Of the Dialectic of Pure Reason in Defining the Conception of the “Summum Bonum” 8 min 4

   Kant distinguishes the supreme good, virtue as worthiness to be happy, from the complete good, which adds happiness distributed in exact proportion to virtue. Virtue and happiness are different in kind, so their connection must be synthetic, a relation of cause and effect, not an identity. The Epicureans and Stoics both sought an identity: for the first, virtue was prudence in pursuing happiness; for the second, happiness was the consciousness of virtue. Since the highest good is necessary a priori, its possibility needs a transcendental deduction.

10. I.2.2 I–II. The Antinomy of Practical Reason, and its Critical Solution 17 min 3

    The antinomy: the desire for happiness cannot produce virtue, and virtue cannot produce happiness in the natural world, so the highest good seems impossible and the law commanding it false. As in the third antinomy of the first Critique, the solution distinguishes appearances from things in themselves: through an intelligent author of nature, virtue may be connected with happiness. Kant defends Epicurus's character, explains the illusion that mistakes moral satisfaction for a sensible motive, and describes “self-contentment”, the negative satisfaction of independence from inclination.

11. I.2.2 III. Of the Primacy of Pure Practical Reason in its Union with the Speculative Reason 6 min 1

    When speculative and practical reason are joined in one cognition, which has priority? Kant argues that if pure reason is practical, as the moral law shows, then theoretical reason must accept propositions inseparably bound to its practical interest, though it cannot prove them itself. This is no license for beliefs that merely serve inclination, such as a sensual paradise or mystical absorption into God. Practical reason has the primacy because all interest is ultimately practical.

12. I.2.2 IV. The Immortality of the Soul as a Postulate of Pure Practical Reason 4 min 5

    The highest good requires complete conformity of the will to the moral law, which is holiness. No finite being can achieve this at any moment, so it is possible only as an endless progress, and that requires the endless existence of the same person: the immortality of the soul. Kant defines a postulate as a theoretical proposition that cannot be proved but follows from an unconditional practical law, and warns against both indulgent morality and fanatical claims to holiness.

13. I.2.2 V. The Existence of God as a Postulate of Pure Practical Reason 18 min 8

    The second element of the highest good, happiness proportioned to morality, requires a cause of nature that acts by intelligence and will according to moral character: God. Belief in God is a moral need, not a duty, and not the ground of obligation; Kant calls it pure rational faith. He explains why the Greek schools failed, reads Christianity's “kingdom of God” as the highest good, and concludes that morality teaches how to become worthy of happiness, with religion adding the hope of it. Humanity must be treated as an end in itself.

14. I.2.2 VI. Of the Postulates of Pure Practical Reason in General 5 min 3

    The three postulates, immortality, positive freedom and God, all arise from the moral law, which is not itself a postulate. They are not dogmas but practically necessary suppositions that give objective reality to ideas speculative reason could only think: the soul of the paralogisms, the intelligible world of the antinomy and the ideal of a first being. This extends knowledge only in a practical respect. How freedom is possible remains unknown.

15. I.2.2 VII. How is it possible to conceive an Extension of Pure Reason in a Practical Point of View, without its Knowledge as Speculative being enlarged at the same time? 21 min 5

    Practical reason gives the ideas of God, freedom and immortality objects, but this yields no synthetic theoretical knowledge of them. The ideas become immanent and constitutive for practical use while remaining regulative for speculation, and reason must guard them against anthropomorphism and fanaticism. Kant restates why physics and metaphysics cannot prove God, since existence is synthetic and design yields no all-perfect author, and concludes that the concept of God belongs originally to morals. Greek theology too arose from moral concern.

16. I.2.2 VIII. Of Belief from a Requirement of Pure Reason 10 min 5

    A need of speculative reason yields only a hypothesis; a need of practical reason, grounded in the duty to promote the highest good, yields a postulate. The righteous man may say: I will that there be a God, freedom and immortality. A commanded faith is nonsense. Theory cannot decide how nature and morality are to be harmonized, so a free moral interest chooses the assumption of a wise Author. This faith may waver but never turns into unbelief.

17. I.2.2 IX. Of the Wise Adaptation of Man’s Cognitive Faculties to his Practical Destination 4 min 1

    Nature seems to have given us faculties poorly suited to knowing God and immortality. Kant argues that this is wise. If God and eternity stood always before our eyes, we would obey the law from fear and hope, conduct would become mechanism like a puppet show, and moral worth would vanish. Because the supersensible is only glimpsed, room remains for disinterested respect for the law.

18. II Methodology of Pure Practical Reason 27 min 8

    The methodology asks how to give the moral law influence on human minds. Kant argues that virtue presented in its purity moves people more than appeals to advantage, which produce only legality and hypocrisy. He points to the general fondness for moral argument in company, proposes a moral catechism and case-based exercises for the young, and warns against sentimental tales of “noble” actions. Examples: an honest man pressed to slander Anne Boleyn, and Juvenal's lines on preferring honour to life. Practice in judgment must be followed by the experience of inner freedom.

19. Conclusion 6 min 5

    Two things fill the mind with admiration and awe: the starry heavens above and the moral law within. The first reduces a person to an animal speck in a boundless universe; the second raises their worth as an intelligence. Astronomy sank into astrology until method rescued it; morality must likewise be studied by method, chemically separating the rational from the empirical in common judgment. Science, critically undertaken, is the narrow gate to the doctrine of wisdom, and philosophy must remain its guardian.