Broad terminological agreement and a shared appreciation of the role of reason in ethics do not mask the very significant disagreements that led to three distinctive philosophical systems: Cartesian dualism, Spinozan monism and Leibnizian pluralism. The book explores the nature of, and offers reasons for, these differences. Phemister contends that Spinoza and Leibniz developed their systems in part through engagements with and amendment of Cartesian philosophy, and critically analyses the arguments and contributions of all three philosophers. The clarity of the authors discussion of their key ideas including their views on knowledge, universal languages, the nature of substance and substances, bodies, the relation of mind and body, freedom, and the role of distinct perception and reason in morals will make this book the ideal introduction to rationalist philosophy.

"Pauline Phemister’s The Rationalists is a well-regulated account of three great seventeenth-century “system builders”, replete with illuminating contrasts and comparisons."

Roger Woolhouse, University of York

"Pauline Phemister’s comparative study of Descartes, Spinoza and Leibniz is an important contribution to the historiography of philosophy as well as a delight to read. The central issues of seventeenth-century metaphysics, including the nature of substance, ideas, God, mind and body, causality and freedom, are treated in depth and with exemplary lucidity. This is simply the best and most comprehensive survey of rationalism available."

Catherine Wilson, City University of New York

Pauline Phemister, Lecturer in Philosophy, University of Edinburgh