Final answer:
Spinoza's argument in Book V, Proposition XXIII suggests that the human mind's essence is eternal, despite the body's destruction.
Step-by-step explanation:
In Book V, Proposition XXIII, Spinoza posits that the human mind cannot be absolutely destroyed with the body, suggesting that some aspect of it is eternal. Baruch Spinoza, unlike Descartes, adopts a form of double-aspect theory, seeing the mind and body as two attributes of the same substance, which he identifies with God. Considering that everything that exists is a mode of God, Spinoza reasons that the essence of the mind, which is knowledge and thought, must have an aspect of eternity since God is eternal. This means that although the physical body may perish, the essence of the mind that pertains to God's nature cannot be entirely destroyed.
On the other hand, René Descartes adhered to a dualistic perspective, with the famous conclusion "cogito, ergo sum" (I think, therefore I am), which asserts the existence of a non-material mind separate from the body. However, modern science has often challenged this view, pointing to the brain as the source of thought processes and questioning the possibility of thought without a physical substrate.