To a large extent, modern philosophy begins with a rejection of tradition. While medieval philosophers such as Thomas Aquinas took great pains to incorporate and reconcile ancient writings, smoothing over any apparent contradictions, early modern philosophers such as Francis Bacon and Rene Descartes encouraged their readers to simply make a clean sweep of the past and start over. Previous thinkers had been deluded by "idols" or mistakes in thinking or had relied too heavily on authority. In the modern age, the wisdom of the past was to be discarded as error-prone. As Descartes observed, Some years ago I was struck by the large number of falsehoods that I had accepted as true in my childhood, and by the highly doubtful nature of the whole edifice that I had subsequently based on them. I realized that it was necessary, once in the course of my life, to demolish everything completely and start again right from the foundations if I wanted to establish anything at all in the sciences that was stable and likely to last. This quest to establish a stable intellectual foundation on which to build something "likely to last" characterized seventeenth- and eighteenth-century European philosophy. British Empiricists, such as Bacon, Thomas Hobbes, John Locke, David Hume, and Thomas Reid, found such a foundation in sensory experience and developed their thought on that basis. On the other hand, the Continental Rationalists, philosophers such as Descartes, Baruch Spinoza, and Gottfried Leibniz, thought the senses inadequate for such a task. They considered reason superior to experience and sought to establish their philosophies on the basis of more certain principles. Immanuel Kant, the greatest of the modern philosophers, sought to combine these two approaches and in so doing developed a uniquely influential system of philosophy. This volume in the Philosophic Classics series includes the key writings of the British Empiricists and Continental Rationalists, along with the work of Kant. In choosing texts for this volume, I have tried wherever possible to follow three principles: (1) to use complete works or, where more appropriate, complete sections of works (2) in clear translations (3) of texts central to the thinker's philosophy or widely accepted as part of the "canon." To make the works more accessible to students, most footnotes treating textual matters (variant readings, etc.) have been omitted and all Greek words have beep transliterated and put in angle brackets. In addition, each thinker is introduced by a brief essay composed of three sections: (1) biographical (a glimpse of the life), (2) philosophical (a resume of the philosopher's thought), and (3) bibliographical (suggestions for further reading). This edition now includes a brief selection from Jean-Jacques Rousseau as well as additional material from John Locke's Essay Concerning Human Understanding and a new translation of Rene Descartes's Meditations. To make room for these changes, I have cut a portion of Immanuel Kant's Critique of Pure Reason and made a number of other small changes. Those who use this volume in a one-term course in modern philosophy will notice more material here than can easily fit a normal semester. But this embarrassment of riches gives teachers some choice and, for those who offer the same course year after year, an opportunity to change the menu.