Rudolf Steiner's philosophical and epistemological writings form the intellectual foundation of his entire body of work. Spanning from his early academic writings in the 1890s through later retrospective surveys, these texts engage directly with the central questions of Western philosophy: How does knowledge arise? What is the relationship between thinking and reality? Can the human being be considered genuinely free? Steiner situates himself in critical dialogue with Kant, German Idealism (Fichte, Schelling, Hegel), and the scientific materialism of the nineteenth century, arguing that a rigorous epistemology — the philosophical science investigating how knowledge comes about — must serve as the foundation for all other inquiry. Key volumes include GA 2 (Steiner's early epistemological study of Goethe's scientific writings), GA 3 (his doctoral thesis, a direct engagement with Kantian epistemology), GA 4 (his central philosophical work on freedom and ethics), and GA 18 (a comprehensive history of philosophical thought).