Spirits and Clocks: Machine & Organism in Descartes (review)

Dennis Des Chene. Spirits and Clocks: Machine & Organism in Descartes. Ithaca, NY and London: Cornell University Press, 2001. Pp. xiii + 181. Cloth, $39.95.

Confronted with the thousandth "entirely new" interpretation of the Cartesian mind-body union, one sometimes wonders whether anything new can in fact be said about the great Descartes. Once again, after his invaluable and prize-winning Physiologia (Cornell University Press, 1996), Des Chene proves that a serious historian, with a keen awareness of historical context, actually can. Unlike the usual accounts of Descartes's animal-machine, Des Chene does not concentrate on the all too familiar set of questions whether or not machines can think, sense, etc. Instead, Des Chene interprets the machine-metaphor the way Descartes meant it to be, viz. as a model for explaining animal and human physiology instead of (cognitive) psychology. Des Chene's central claim is that the Traité de l'Homme and Descartes's later (unpublished) physiological tracts are an attempt to replace scholastic commentaries on Aristotle's De Anima, itself discussed in this book's companion volume Life's Forms (Cornell University Press, 2000). Spirits and Clocks investigates how Descartes's general mechanistic program (outlined in Physiologia) is applied to the field of animal and human life. This project in itself had a far more lasting influence than Descartes's specific and often bizarre physiological explanations. Therefore, Des Chene rightly concentrates on the philosophical aspects of Descartes's general project of "mechanizing" physiology. His short but illuminating book studies a wide range of ontological, epistemological, and even aesthetic aspects of the machine metaphor and, although this is not the express goal of the book, it also sheds new light on the epistemology and metaphysics of the Meditations. In this sense Spirits and Clocks is not only a significant contribution to the history of biology but first and foremost a must for historians of philosophy.

Des Chene explains that the use of a machine model in physiology was neither new nor entirely unacceptable to the Aristotelians. What is new is Descartes's use of it. His mechanistic understanding of the body as a machine is incompatible with accepting the soul as the source of life and the principle of all our physiological and psychological capacities, while Aristotelians had no problem in accepting both the soul and certain machine models of the body. (Aristotle himself uses the lever to explain animal motion.) Des Chene sketches Descartes's attempt to explain all physiological processes by means of the physical properties of material parts that obey the general laws of motion, excluding all talk of ends. In this context, the use of illustrations is of considerable importance: though they cannot per se convey a denial of a "soul-model" of physiology, they strongly suggest that the (mechanistically understood) machine is all there is to say about the functions of human and animal bodies. Des Chene offers an interesting, albeit sometimes somewhat speculative and ahistoric, discussion of the aesthetic aspects of the machine model.

As Des Chene showed in his Physiologia, the rejection of teleology is one of the main goals of Descartes's physics. However, although Descartes may be successful in rejecting the view that stones fall down from some kind of desire to reach their final destiny, he is less successful in denying that the eye is meant for seeing (and hence for our self-preservation). Des Chene gives a truly fascinating account of the limits of Descartes's denial of teleology in physiology. This includes questions about the physical unity of the human body: how can I explain why I have this body and how can I even identify this body as a unit without invoking ends? Similarly, Descartes takes the healthy, "normally" functioning body as the norm of his investigations. But, again, can he do so without acknowledging some form of teleology? Descartes's answer in most of these cases is that the final goals...