As a practicing life scientist, Descartes must have a theory of what it means to be a living being. In this paper, I provide an account of what his theoretical conception of living bodies must be. I then show that this conception might well run afoul of his rejection of final causal explanations in natural philosophy. Nonetheless, I show how Descartes might have made use of such explanations as merely hypothetical, even though he explicitly blocks this move. I conclude by (...) suggesting that there is no reason for him to have blocked the use of hypothetical final causes in this way. (shrink)

According to Kepler and Descartes, the geometry of the triangle formed by the two eyes when focused on a single point affords perception of the distance to that point. Kepler characterized the processes involved as associative learning. Descartes described the processes as a “ natural geometry.” Many interpreters have Descartes holding that perceivers calculate the distance to the focal point using angle-side-angle, calculations that are reduced to unnoticed mental habits in adult vision. This article offers a purely psychophysiological interpretation of (...) Descartes’s natural geometry. In his account of perceived limb position from the Treatise on Man, he envisioned a central brain state that controls ocular convergence and thereby co-varies with the distance from observer to object. A psychophysiological law relates the visual perception of distance to this brain state. Descartes also invokes more traditional theories of distance and size perception based on unnoticed judgments, yielding a hybrid account. (shrink)

In this article I dispute the claim, made by several contemporary scholars, that Spinoza was a naturalist. ‘Naturalism’ here refers to two distinct but related positions in contemporary philosophy. The first, ontological naturalism, is the view that everything that exists possesses a certain character permitting it to be defined as natural and prohibiting it from being defined as supernatural. I argue that the only definition of ontological naturalism that could be legitimately applied to Spinoza's philosophy is so unrestrictive as to (...) tell us nothing about the content of his ideas. The second, methodological naturalism, is the view that the natural sciences are the best means of finding out substantial truths about the concrete world. I present some historical research showing that Spinoza's way of positioning himself with respect to other philosophers in the Dutch Republic casts very serious doubt on the claim that he was a methodological naturalist. This adds further weight to arguments that have already been made against the naturalist reading of Spinoza. (shrink)