In the Ethics, Spinoza famously rejects freedom of the will. He also offers an error theory for why many believe, falsely, that the will is free. Standard accounts of his arguments for these claims focus on their efficacy against incompatibilist views of free will. For Spinoza, the will cannot be free since it is determined by an infinite chain of external causes. And the pervasive belief in free will arises from a structural limitation of our self-knowledge: because we are aware of our actions but unaware of their causes, we suppose that we alone must be responsible for them. Yet I argue that the standard accounts miss a further element of Spinoza’s arguments that also targets compatibilist views on which free will is consistent with a specific kind of determination—namely, self-determination in accordance with our value judgments. For Spinoza, we are misled not only in supposing that our actions lack external determination but also in thinking that they are determined by our representations of value. In fact, our actions are determined by our appetites, which are blind to our value judgments. And the pervasive belief that our actions are determined by such judgments arises from the projection of value onto the objects we seek. As he denies us free will, then, Spinoza also denies us a capacity central to agency—the capacity to determine our actions in accordance with our ideas of the good. This makes his arguments against free will more consequential, and more radical, than commonly assumed.