614 JOURNAL OF THE HISTORY OF PHILOSOPHY 34:4 OCTOBER 1996 commentators that Descartes denies that the causal process of perception involves the awareness of intermediaries. However, when addressing our epistemological position, he clearly states that mental intermediaries are involved in perception. She suggests an explanation of this, and then gives a plausible interpretation of resemblance claims between ideas and objects. LiUiAlanen in "Sensory Ideas, Objective Reality, and Material Falsity," and Ann Wilbur MacKenzie in "The Reconfiguration of Sensory Experience ," discuss, in part, whether sensations have objective reality. Alanen gives an account of material falsity according to which sensations do have objective reality, but MacKenzie's account, which involves distinguishing between sensations, which do not represent and have no objective reality, and concepts of sensations, which represent sensations, is clearer. The main thesis of MacKenzie's paper is that the Opticscontains a new theory of represerLtation, inclusive of sensory ideas, in which a causal nexus replaces resemblance. However, later, sensory ideas are no longer taken to represent, since they do not exhibit their causes. The collection begins with three unrelated papers gathered under the tide "Reason , History, and Method." Stephen Gaukroger, in "The Sources of Descartes's Procedure of Deductive Demonstration in Metaphysics and Natural Philosophy," argues that Descartes's method of demonstration in the Meditations and the Principles is based on the structure of Jesuit textbooks. Tom Sorell, in "Descartes's Modernity," takes the thesis that knowledge is antierudition to be the crucial modern element in Descartes. The problems in philosophically treating historical writings in philosophy, and the problems with an adequate treatment of Descartes are discussed by Bernard Williams, in "Descartes and the Historiography of Philosophy." The remaining papers deal with God, substance, and the mind-body union. In "God without Cause," Carol Rovane constructs a Cartesian argument for God's existence which moves from doubt to the idea of perfect knowledge, to one of the perfect being, and finally to its existence. "Descartes's Concepts of Substance," by Peter Markie, and "Descartes: The End of Anthropology," by Stephen Voss, together give a thorough discussion of substance and the nature of the union between mind and body. In arguing that Descartes uses three different notions of substance, Markie supposes that the mind-body union constitutes a substance. However, Voss argues that although Descartes talks of a substantial union in the Meditations, he abandons the notion by the Principles. Voss's paper also includes an appendix consisting of an extensive taxonomy of Descartes's statements on the nature of the mind-body union. LAURA KEATING Hunter College,CUNY Margaret J. Osier. Divine Will and the Mechanical Philosophy. Cambridge University Press, 1994. Pp. xi + 984. NP. Divine Will and the Mechanical Philosophyis a work of intellectual history par excellence, both for its breadth of theme and its depth of careful analysis. Osier masterfully weaves together the theological, epistemological, methodological, and physical doctrines of the BOOK REVIEWS 6~ 5 seventeenth century's two greatest opponents--both champions of the new mechanical philosophy--Pierre Gassendi (159a--1655) and Ren~ Descartes 0596-165o). Beyond bringing the historical and theological context into focus, Osier argues that "the issues that separated Gassendi and Descartes stemmed directly from their divergent understandings of God's relationship to the creation" (167). For those who tend to deemphasize the importance of the theological context in understanding these thinkers, this work will make you think again. Osier lays out carefully not only the different and unique routes each thinker travelled to arrive at his consideration of theological matters , but also the strong philosophical ties that hold between their divergent views on the priority of God's will/intellect, the contingency/necessity of the natural order, the limits/reliability of rational methods, and the atomist/geometric theories of matter. Osler's work is divided into two parts. Part One, Chapters 1-6, is an examination of the theological context for the new philosophies of nature that emerged in the seventeenth century. Osier places Gassendi firmly in the voluntarist tradition of Ockham, and Descartes firmly in the intellectualist tradition of Aquinas. Osier argues that although Descartes and Gassendi shared the project of designing a new mechanized philosophy of nature, their divergent conceptions...