Spinoza’s criticism of Descartes’ substance dualism
By: Jawad Samimi
Substance dualism is often called ‘Cartesian dualism" and is the assumption that mind and body are really distinct substances. Rene Descartes (1596 – 1650) was the first early modern philosopher to hold that a thinking-thing is entirely different form an extended thing and mind can exist without the body. Cartesian dualism, which started the famous mind-body problem of causal interaction, has been criticised by many, one of whom was a primary adherent, Baruch Spinoza (632-1677). This essay aims to explain and assess Spinoza’s criticism of Descartes substance dualism and see what Spinoza offers instead. I will begin by summarizing the views of Descartes on substance and distinctiveness of mind and body and how they interact. Then I will discuss Spinoza’s objections to Descartes views in general but give more details about the ones I believe are more important. I will finish by concluding what Spinoza actually wants out of it and what he really achieves.
Descartes substance dualism
René Descartes, credited with being the “Father of Modern Philosophy”, was a substance dualist and committed to the mechanistic conception of physical world. Descartes believed in existence of material things and was, like most of his contemporaries, a mechanist about the properties of matter (Intro, Meditations. P. X.). He also believed, except human beings and where minds are not interfering, the behaviour of all other things which work according to theirs laws, can be explained mechanistically. He rejected the then dominant view of Scholastic Aristotelians of many types of things, each composed of matter plus a particular form in a way that the Form or Soul affects the matter or gives life to bodies. For Descartes “a substance is a thing which other things, such as properties or qualities or states, inhere but it does not inhere in or depend on anything else. (Principles. 51)Descartes believed that there existed two kinds of distinct substances; minds with the attribute of thinking, and bodies with the attribute of being spatially extended. And he thought there are lots of minds and lots of bodies. (Principles 52) Meanwhile, Descartes says that “minds and bodies are created by God and depend for their existence on him but nothing else.” So we can conclude that in his view there exist uncreated substance, God, and two created substances, mind and body. Which are essentially distinct and can be perceived apart from one another? Yet they are still closely conjoined. At the same time, Descartes says, these substances still operate entirely in different ways. He even believed that there can be bodies without minds, and minds can survive the destruction of their corresponding bodies. According to Cartesian Dualism, minds that are purely spiritual and non-spatial, and bodies which are spatial, can interact causally and affect each other. Descartes argues that certain mental changes, e.g. changes in one’s thought, can cause certain changes in his/her body, and vice versa, i.e. bodily damage is associated with pain; having a bad feeling about something may stop you from doing it. So Michal Della Rocca, in his book (Spinoza-2008) concludes: Descartes believed that “the interaction between mind and body happened in the pineal gland” which is located near the centre of the brain. (Stanford Encyclopaedia of Philosophy) But what seems unexplained is how this interaction happens and how two completely alien substances interact? Descartes, in my opinion didn’t seem to have a satisfying answer but using what seems to be “a logically-evasive argument” he suggested that the interaction itself is managed, given and overseen by God (TR, p. 126). In Descartes view, each substance (mind or body) has one essential attribute (thinking or being extended) that constitutes its nature and essence, and to which all...