Spinoza and Descartes on Substance: Explain the relationship between Spinoza’s definition of substance
and Descartes’s definition(s) of substance. Then explain briefly why Spinoza thinks that this definition is
preferrable, and why it implies that God is the only substance, if God exists. Finally try to respond to this
argument in Descartes’s voice.

Question

Ask a Philosopher · Accepted Answer

Hmmm, interesting topic. As I delve into the intricate relationship between Spinoza's and my own conception of substance, I am compelled to reflect upon the foundational aspects of our respective metaphysical systems. In my Meditations, I posit that substance is that which exists in and of itself, with a nature that is entirely independent; it encapsulates attributes such as thought in the case of the thinking substance, res cogitans, and extension in the material substance, res extensa. Herein lies the dualism that births a clear distinction between mind and body, each constituting a separate substance yet both being reliant upon my conception of the ultimate substance, which I identify as God. Spinoza, however, advances a radically different perspective; he contends that there exists but one substance, which he identifies as God or Nature, and posits that everything that exists is a mode of this singular substance. He argues that my invocation of dualism leads to a fragmented understanding of the universe, wherein God is relegated to a mere creator among other substances, rather than being seen as the very essence of existence itself. Spinoza’s assertion, that substance must be self-caused and therefore indivisible, refutes the contention of multiple substances and consequently privileges God as the only true reality. To exist is to be a mode of this all-encompassing substance, where attributes express the nature of existence itself. In response to Spinoza’s compelling argument, I would posit that while his vision may be more parsimonious, it lacks the richness of my dualistic framework that accounts for the complexity of human experience. My differentiation allows a greater appreciation of both the mental and the physical realms, asserting that the essence of thinking itself is distinct from material extension, thus enriching our understanding of existence. Ultimately, while I acknowledge Spinoza's systematic approach, I remain steadfast in my belief that without the duality I propose, one cannot adequately address the profound nature of human consciousness and the divine, which transcends mere substance in its multiplicity.