The Breakdown of Cartesian Metaphysics (review)

296 JOURNAL OF THE HISTORY OF PHILOSOPHY 28"2 APRIL 199o Richard A. Watson. The Breakdown of Cartesian Metaphysics. Atlantic Highlands, NJ: Humanities Press, 1987. Pp. xii + 240. Cloth, $45.oo. This book is essentially a reissue of Richard Watson's Doun~faUof Cartesianism (1966), with minor revisions and some cosmetic changes, such as retitling of headings. Added to the end of the volume are four more recently published papers: "Transubstantiation among the Cartesians" (from the 1982 collection Problemsof Cartesianism edited by T. Lennon eta/.); a brief piece on La Forge (from Studia Cartesiana, 1982); and two short and sweeping attacks on Cartesian metaphysics and epistemology: "What Moves the Mind?" (APQ, 1982) and "Descartes Knows Nothing" (HPQ, 1984). An introductory chapter (which has also appeared before) outlines the author's conception of the history of philosophy as involving the construction of an interpretative "skeleton" on which "the flesh of the text can be reasonably shaped" (1 t). The virtues of Watson's 1966 book, which forms the meat of the present volume, are well known. It provides a fascinating survey of the various ways in which Descartes's supporters and critics responded to two central difficulties of Cartesianism: "How can two unlike substances causally interact?" and "How can mind know matter?" On the latter question, the work of Simon Foucher is explored to good effect, to pinpoint just what a problem the Cartesians had on their hands in trying to explain how mental ideas could represent material things. On the former question, Watson's achievement is to show how our understanding of the Cartesian system can be advanced by scrutinizing the manoeuvres of such lesser-known figures as Robert Desgabets and Pierre-Sylvain Rtgis. Of the newer papers which augment the present volume, perhaps the most controversial is "What Moves the Mind?" where Watson argues that Descartes cannot avoid the doubly paradoxical conclusion that "thinking is a mental plenum and--as such---is in its own way as homogeneous and thus as empty as is the material plenum" (187). If we take the material world first, talk of an "empty plenum" is of course a contradiction in terms; but Watson's point seems to be that although Descartes wantsthe extended universe to be "full," his characterization of it in terms of pure, homogeneous, featureless extension means that it is, in effect, indistinguishable from empty space (only motion, an extrinsic feature specially imparted by God, can generate bod/es).There issomething telling about this criticism (indeed as early as the 164os critics such as Gassendi voiced convincing objections to the Cartesian project of founding real physics on mathematical extension alone); but one feels that Watson would have strengthened his case by allowing space for some analysis and rebuttal of Descartes's own attempts to deny emptiness (e.g., at Pr/nc/pies 2.18) and to establish (e.g., in the correspondence with More) that impenetrability belongs to the essence of extension. As for the second part of Watson's thesis, viz., that the mind must also be effectivelyempty for Descartes, the obvious objection is how this is to be reconciled with Descartes's description of the mind as a "treasure house" of innate ideas (thesaurus,Medit. 5, and many other similar passages). Watson's strategy here is to argue that such ideas turn out to be empty of content. Thus he claims that the idea of God, for example, is merely an idea of a necessarily-existing-somethingwhich cannot be described: "The idea of God is empty, it is the homogeneous/s of Parmenides, the night in which all cows are black" (188). Yet what of the other properties which Descartes BOOK REVIEWS 297 attributes to God--omnipotence, omniscience, and so on? Watson simply observes that "we cannot comprehend these notions" (ibid.), but this seems much too swift. Descartes readily admits that infinity, for example, cannot be "grasped" (comprehendere) by the human intellect, while insisting, with some arguments to back his claim, that it is a term whose meaning we nevertheless "understand" (intellegere). Again, what of our innate mathematical notions? Admittedly these are highly general and abstract ("simplicissima generalia," as Descartes puts it in the Meditations) but this does not...