This book attempts to explain The Meditations (1641), a classic of Western philosophy in which Descartes tries to reach a predetermined end ("perfect certainty") by means of a definite method ("the method of doubt"). The author argues that many problems of interpretation—including notorious problems of circularity—arise from a failure to recognize that Descartes' strategy for attaining certainty is not to add support for his beliefs, but to subtract grounds for doubt. To explain this strategy, Rubin views Descartes as playing the role of a fictional character—The Demon's Advocate—whose beliefs are, in some respects, mirror images of Descartes' own. The purpose of The Meditations, he contends, is to silence The Demon's Advocate.