Kant’s views on the relation between freedom and moral law seem to undergo a major, unannounced shift. In the third section of the Groundwork, Kant seems to be using the fact that we must act under the idea of freedom as a foundation for the moral law. However, in the Critique of Practical Reason, Kant claims that our awareness of our freedom depends on our awareness of the moral law. I argue that the apparent conflict between the two texts depends on a reading of the opening paragraphs of Groundwork III, and on an interpretation of Kant’s claim that we “act under the idea of freedom”, that is implausible on textual and on philosophical grounds. I then present an alternative interpretation of what Kant means by “acting under the idea of freedom” and of the opening paragraphs of Groundwork III. I argue that the only substantive conclusion of these paragraphs is that no theoretical proof of freedom is necessary. Moreover I argue that although these paragraphs raise concerns about the validity of the moral law, these concerns and Kant’s answers to them, do not give rise to any significant conflict with his views in the Critique of Practical Reason.