In the Critique of Pure Reason, Kant famously criticizes traditional metaphysics and its proofs of immortality, free will and God's existence. What is often overlooked is that Kant also explains why rational beings must ask metaphysical questions about 'unconditioned' objects such as souls, uncaused causes or God, and why answers to these questions will appear rationally compelling to them. In this book, Marcus Willaschek reconstructs and defends Kant's account of the rational sources of metaphysics. After carefully explaining Kant's conceptions of reason and metaphysics, he offers detailed interpretations of the relevant passages from the Critique of Pure Reason (in particular, the 'Transcendental Dialectic') in which Kant explains why reason seeks 'the unconditioned'. Willaschek offers a novel interpretation of the Transcendental Dialectic, pointing up its 'positive' side, while at the same time it uncovers a highly original account of metaphysical thinking that will be relevant to contemporary philosophical debates.

Introduction; Part I. From Reason to Metaphysics: 1. Kant's conceptions of reason and metaphysics; 2. The logical use of reason and the logical maxim; 3. The supreme principle of pure reason; 4. Understanding the transition passage (A307-8/B364); 5. The transition from the logical maxim to the supreme principle of pure reason; Conclusion to Part I; Part II. The Other Side of the Transcendental Dialectic: 6. The system of transcendental ideas; 7. The paralogisms and antinomy arguments as 'necessary inferences of reason'; 8. Reason and metaphysics in the transcendental ideal and the appendix; 9. Transcendental realism and Kant's critique of speculative metaphysics; Conclusion to Part II.

Marcus Willaschek is Professor of Modern Philosophy at Johann Wolfgang Goethe-Universität Frankfurt. He is the author of Praktische Vernunft: Handlungstheorie und Moralbegründung bei Kant (1992) and Der Mentale Zugang Zur Welt: Realismus, Skeptizismus und Intentionalität (2003), and an editor of the three-volume Kant-Lexikon (2017).