Substance, nature, and necessity › Necessity includes our deliberation

Part I, proposition 29 says that nothing in nature is contingent: things are determined to exist and act by the necessity of the divine nature. Part II, proposition 48 denies an absolute or free will in the mind and describes particular volitions as determined through causes. Spinoza consequently does not treat deliberation as an exception to the rest of nature.

This position differs from the assertion that thinking makes no difference to what happens. If deliberation forms part of the causal explanation of an action, it can matter precisely because it has a place in that explanation. A person who considers a consequence and changes a plan need not stand outside causation in order for the consideration to matter. This is a reconstruction of how the ethical project can coexist with the necessity asserted in Part I.

Definition VII of Part I calls free what exists from the necessity of its own nature and is determined to act through itself alone. Absolute independence in that sense cannot simply be transferred to a finite human being. Part IV, proposition 4 says that a human being cannot cease to be part of nature or undergo only changes explicable through that person's own nature. External causes remain part of our situation.

Human freedom must therefore be understood with that limit in view. Spinoza's ethical distinctions concern how far we act through adequate understanding and how far we are passive. They do not promise that a sufficiently thoughtful person becomes an independent substance, loses bodily needs, or gains complete control of circumstances.