The major difference between Spinoza and Descartes is that Spinoza cannot assert the freedom of the will because he is a determinist, whereas Descartes affirms free will, making this difference quite significant for their ethical systems.

If one dislikes Spinoza's conclusions, there are two primary ways to respond: first, one can question his definitions and axioms by asking whether the axioms are truly axiomatic and whether the definitions are arbitrary or defensible; or second, one can examine his logical reasoning.

Spinoza published the Tractatus Theologico-Politicus in 1670, in which he denies that there is any specially revealed divine truth, marking a major work of theological critique.

Unphilosophical people are incapable of conceiving God clearly because they are by training incapable of understanding what they cannot imagine, being tied to their senses rather than capable of rationalist a priori knowledge.

In Spinoza's system, there is no notion of separate substances; there are only distinguishable attributes and modes, so one finite mode can be distinguished from another finite mode but not by virtue of substance distinction.