Can Determinists Act Under the Idea of Freedom?

Determinism which denies freedom of action is a common philosophical view. Is the action of such determinists incompatible with Kant's claim that a rationally willed being "cannot act otherwise than under the idea of freedom" [G 4, 448]? In my paper, I examine Kant's argument for this claim at the beginning of the Third Section of the Groundwork and argue that it amounts to the assertion that one cannot act while being aware of being guided by invalid principles. Belief in determinism does not necessarily amount to such awareness. A structurally similar argument based on the contrast between deliberation and prediction is examined and similarly found wanting. [ABSTRACT FROM AUTHOR]