Journal of the History of Philosophy

Desmond Clarke, commentator on Cartesian natural philosophy, has now published an interpretation of Descartes's dualism, a theme which can hardly be said to be underrepresented in the literature. The monograph is divided into nine chapters concerned with explanation, sensation, imagination and memory, the passions, the will, language, thought, substance, and property dualism—yes, property dualism.

The book pushes forward a reading of Descartes's theory of mind, made from a perspective which Clarke has adopted over the last three decades or so, that maintains that Descartes was primarily (and willingly) a scientist and incidentally (and reluctantly) a philosopher. From this viewpoint, according to Clarke, natural philosophy provides the paradigm for genuine explanation in Descartes's metaphysics. Furthermore, given that Descartes rejects Scholastic substantial forms and real qualities as explanatorily infertile and since substances are equally unfruitful, substances play no explanatory role in his system of philosophy. Substance dualism is not at the center of Descartes's philosophy of mind; his account of explanation is. This makes Descartes not a substance dualist; but a property dualist. So argues, in very broad strokes, Clarke. [End Page 116]

Unlike us, Descartes did not draw a sharp distinction between philosophy and science. For him, these two realms of enquiry were part of a unified realm of knowledge, what he deemed scientia or philosophy in the wider sense. Hence his use of the instructive metaphor of philosophy as a tree, whose roots are metaphysics, the trunk physics, and the branches the other sciences which he reduces to three principal ones, namely medicine, mechanics, and morals (Letter Preface to Picot, French translation of the Principles of Philosophy, Oeuvres de Descartes, ed. C. Adam and P. Tannery [Paris: Vrin, 1989], 14). However, Descartes did distinguish the roots from the trunk, that is, metaphysics (or "first philosophy") from physics (or "natural philosophy"). Commentators on Descartes's system of philosophy ignore his natural philosophy at their peril, for it does shed considerable light on his metaphysics. But, likewise, Descartes's philosophy greatly illuminates his science. It is for this reason that I want to cast doubt on Clarke's apparent scientific imperialism in which Descartes's methodological, epistemological, and metaphysical concerns are forced to play second fiddle to his scientific views. We cannot neatly fit Descartes's metaphysical views into Clarke's scientific mold, nor can we force them in, without incurring serious error. I do not think that one has to choose between one and the other as being primary, between the tree of knowledge and the inverted tree of knowledge. We need to keep in mind that in Descartes's system of philosophy, both science and philosophy are interconnected and that both parts elucidate each other.

Clarke's attempt to eliminate substance from Descartes's account of mind is problematic. True, the term 'substance' is an extremely ambiguous one and Descartes's comments about it are often blurred and puzzling. On the one hand, one must concede that the concept of substance plays a small role in Descartes's natural philosophy, in which although the material universe is depicted in terms of extended substance or res extensa, physics is ultimately unwrapped by way of laws describing the behavior of particles in virtue of their size, shape, and motion. But, in contrast, substance plays a far more prominent role in his metaphysics, not to mention in his theology. This leads to a related point. Clarke overlooks the importance of theology for Descartes's philosophical project and the role of God in Cartesian natural philosophy.

The level of argument drops considerably in the final chapter, where Clarke offers an uncritical and not very clear survey of naming and necessity, the identity theory, anomalous monism, and property dualism. This chapter seems in tension with his disapproval of anachronistic readings of Descartes (8-9) and contains some serious slips. Clarke's answer to his own question "Was Descartes, then, a substance dualist" is a mind boggling "Yes and no" (258), and his claim that Descartes was a property dualist, collapses under...