The metaphysics of determination, from Descartes to Spinoz

Andrea Sangiacomo

University of Groningen


One of the major features of Spinoza’s Ethics is a particular conception of the nature of finite things, which are there considered not only as modifications of an infinite and unique substance, but also as endowed with active powers to operate in the world. However, according to several scholars, such an “ontology of activity” would be at odd with the mechanical picture offered by the new science (Gaukroger 2006). Rather, it would be a Spinozean revival of some aspects of the scholastic or Renaissance thought (Zac 1963, Viljanen 2011). This paper aims at challenging the opposition between mechanism and the notion of activity. In particular, I will show that Spinoza elaborates his “ontology of activity” by refining at least one concept crucial to Cartesian physics, namely, the notion of “determination”. This way, Spinoza’s essentialism and his account of active powers will appear as an attempt to take a step further in a debate opened by the new natural philosophy itself.

In its technical meaning, Descartes uses the concept of “determination” to express the directional aspect of motion. In the physical plenum, external causes usually determine bodies to move along curvilinear paths. However, bodies have also an internal determination to follow straight paths. In Descartes’ account, though, the mutual consistency of internal and external determination is questionable.

In his Principles of Cartesian Philosophy, Spinoza introduces the notion of “force of determination” in an attempt to resolve such a problem. In a nutshell, his strategy consists in making more explicit the link between the body’s force (or quantity of motion) and the internal determination to maintain its own path. By introducing the concept of “force of determination”, Spinoza attempts to explain to what extent a certain body is internally determined by its own force to maintain its movement in a certain direction, by opposing the external determination it receives from other bodies. Accordingly, using this notion, Spinoza works out an interesting procedure to decompose the reciprocal contrarieties between colliding bodies.

I will show that such a procedure provides a crucial model for understanding causal relations in the Ethics. Here, Spinoza reproduces the distinction between internal and external determinations. Both these kinds of determination express the ways in which things bring about their effects in composition with external causes. Such a distinction grounds Spinoza’s claim concerning the possibility of checking external determinations in order to improve the power to act. In this sense, Spinoza maintains a (Cartesian) modal distinction between causation (i.e., the effects that a thing can produce in virtue of its own essence) and determination (i.e., how those effects are actually produced). Accordingly, I argue that the account of physical interactions put forward concerning the “force of determination” provides a general model for Spinoza’s ontology.
This way, I will show that Spinoza refines the concept of determination exactly to solve the contrast between internal causal efficacy (introduced by the conatus doctrine) and extrinsic causation (arising from the causal chain in which each thing is necessarily inscribed).