The Shortcomings of a Concept Inertia and Conatus in the Philosophy of Spinoza

Abstract

n the third part of the Ethics, Spinoza express the desire to talk about “human actions and appetites just as if it were a question of lines, planes, and bodies” (E3, Appendix).1 With this sentence, it seems clear that Spinoza sides with Hobbes and Descartes and that he wants to construct a mechanistic theory of the affects. In the same part of the Ethics, Spinoza also introduces the concept of conatus: “Each thing, as far as it can by its own power, strives to persevere in its being” (E3P6), Spinoza says. One will immediately understand this concept of conatus as the core concept of his mechanistic theory of the affects, the concept without which this mechanistic account of the affects would be impossible. However, in the second part of the Ethics, there is another concept that could have accomplished that same goal, namely, the principle of inertia. In the words of Spinoza, “A body which moves or is at rest must be determined to motion or rest by another body, which has also been determined to motion or rest by another, and that again by another, and so on, to infinity” (E2L3). Interestingly enough, in the philosophy of Hobbes, the concept of endeavour/conatus is much nearer to the Spinozistic principle of inertia in its meaning than it is to the Spinozistic version of the conatus. However, Hobbes is still able to construct a deeply mechanistic theory of the affects with this concept, and one may think that Spinoza should have been too. In this paper, I aim to address the question of why Spinoza has decided to use the concept of conatus rather than the principle of inertia to achieve his goal of constructing a mechanistic theory of the affects. I will then argue that for this