This paper critically evaluates an objection to introspective arguments for human freedom found within Spinoza's Ethics. The objection-- which we call Spinoza's dream argument -- challenges the evidentiary value of a person's experience of her own freedom by pointing out that some choices made within dreams are experienced as no less free than choices made while awake despite the fact that choices made within dreams are not free. After reconstructing Spinoza's dream argument, we critically evaluate it, concluding ultimately that it (...) fails in two respects. First, we draw upon the results of an experiment we conducted that suggests that dreamt choices are not experienced as free to the same extent as choices made while awake. Second, we argue that there is no compelling justification for the claim that choices made within dreams are not free. (shrink)