Descartes understood the subject matter of physics (or natural philosophy) to encompass the whole of nature, including living things. It therefore comprised not only nonvital phenomena, including those we would now denominate as physical, chemical, minerological, magnetic, and atmospheric; it also extended to the world of plants and animals, including the human animal (with the exception of those aspects of the human mind that Descartes assigned to solely to thinking substance: pure intellect and will). Descartes wrote extensively on physiology and (...) on the physiology and psychology of the senses. This chapter examines the notions of *physiology* and *psychology* in medical and natural philosophical works of Descartes' day; follows his efforts to bring physiology into his mechanistic idiom; considers the relation between physiology of the animal machine and psychological functions that yield functionally appropriate behavior; goes into his physiology and psychology of vision; and elaborates the tension in Descartes' works between his metaphysically supported micro-corpuscularism and his discussion of the animal machine as an organic unity comprising various functionally and teleologically characterized systems. The chapter draws on Descartes' works in both metaphysics and natural philosophy, including his Treatise on Man (originally published as L'Homme, 1664). (shrink)

An understanding of the relationship between metaphysics and natural philosophy - or, as we might now say, between philosophy and science - is fundamental to understanding the rise of the "new science" of the seventeenth century. Twentieth-century scholarship on this relationship has been dominated by the thoughbt of Ernst Cassirer, E. A. Burtt, A. N. Whitehead, and Alexandre Koyre. These authors found a common core in the mathematization of nature, which they ascribed to a common Platonic or Pythagorean metaphysical presupposition, (...) on the part of Copernicus, Kepler, Galileo, and Descartes, that the book of nature is written in mathematical characters. Taking Burtt as its primary stalking horse, this chapter challenges this view by finding significant differences in the relations to metaphysics of major actors such as those just named. It does this in part by recognizing that, in the seventeenth century, metaphysics was an intellectual practice that one engaged in wittingly. By contrast, Burtt adopted a historiographical approach in which metaphysics consists of the nonempirical presupposition of an age (a position advanced by R. G. Collingwood). That approach, although valid within its limits, distorts or omits from consideration the witting practice of metaphysics by figures such as Kepler and Descartes. And it makes metaphysicians of Copernicus and Galileo, who are better classified as a mathematical astronomer and a mathematical natural philosopher and writer on astronomy. The chapter ends with some reflections on purportedly aphilosophical history of science. (shrink)