Metaphysics · Ethics
Are human actions causally determined, and can people be free and morally responsible if they are?
Free will is compatible with causal determinism: an action is free when it flows from the agent's own reasons, desires, or character, whether or not those are themselves causally determined.
Held by Stoicism
Causal determinism is true and incompatible with free will, so human beings do not have free will.
Free will is incompatible with determinism, and we have it: at least some choices are not causally necessitated.
Held by Epicureanism
Schopenhauer denies the liberty of indifference: every act follows necessarily from the character meeting a motive, and freedom belongs not to acting but to being, to the intelligible character that the will is as thing-in-itself.
A thought experiment constructs an imagined case and reasons through it to isolate a principle, intuition, possibility, or conceptual consequence.
The free-will problem asks two linked questions: whether human action is causally determined and whether determination would rule out freedom and responsibility. Hard determinists answer that actions are determined and therefore not free; compatibilists argue that determined action can still be free; libertarians hold that at least some free actions are not determined.
Keeping both questions explicit makes these three positions genuine rivals rather than three answers to different problems.