This panel aims to explore Galen's philosophy of medicine by focusing on the central role he assigns to rational, verifiable, and experiential knowledge as the foundation of medical art. Far from being a merely technical therapeutic practice, Galenic medicine emerges as a rigorous scientia, grounded in epistemological principles that, in certain respects, anticipate an attitude akin to an ante litteram positivism. Through an analysis of Galen's major medical and philosophical treatises, the panel investigates the relationship between logos, peira, and enargeia, showing how direct observation of the body, clinical experience, and rational demonstration jointly contribute to the construction of an objective and cumulative medical knowledge. Particular attention is paid to Galen's critique of both radical empiricism and abstract speculation, in favor of a methodological synthesis capable of ensuring epistemic certainty and therapeutic reliability. Finally, the panel reflects on the normative and formative function of medical knowledge in Galen's thought, highlighting how medicine becomes an epistemological model for other disciplines and a privileged framework for understanding the relationship between nature, knowledge, and truth in the ancient world.