The Critique of Pure Reason, written by Immanuel Kant, is a foundational philosophical work aimed at examining the nature and limits of human reason in relation to knowledge and metaphysics. Kant seeks to establish the boundaries of what pure reason can achieve independently of experience and to defend the possibility of metaphysics rooted in a critical understanding of reason itself rather than speculative metaphysics. Kant's work achieves a synthesis between rationalism and empiricism by asserting that while all knowledge begins with experience, not all knowledge arises from it. He argues that the mind actively shapes experience through innate forms and categories, making synthetic a priori knowledge possible, unlike empiricists who deny this. This leads to his famous "Copernican revolution" in philosophy by emphasizing how reality as we know it is partly constructed by our mental faculties. The book is divided into two major parts: the Transcendental Doctrine of Elements, which explores the sources and structure of human knowledge, and the Transcendental Doctrine of Method, which sets out guidelines for the use of pure reason in metaphysics. It includes discussions about space and time as forms of intuition, causality, and the limitations of metaphysical speculation, including famous contradictions (antinomes) concerning the nature of the universe, freedom, and necessity. Overall, the Critique is both a "negative" critique that limits reason's speculative reach and a "positive" foundation for moral and practical reason. Its influence reshaped philosophy by grounding knowledge on the capacities and limits of the human mind rather than on metaphysical speculation about the external world beyond experience.
