 Cohen’s first attempt to apply the transcendental method to ethics was his Kant’s Foundations of Ethics, which first appeared in 1877. In it, he is motivated by a dissatisfaction that Kant could not provide a transcendental deduction of the moral law the way he had for the categories in the first Critique (Cohen 1877, 179). In the first Critique, Kant had argued that the categories are justified, because they are necessary conditions for the possibility of experience. But in the Critique of Practical Reason, he argued that the moral law cannot be justified as a necessary condition of experience, because we can experience ourselves only as beings whose actions have natural causes, and cannot experience ourselves as free moral agents. Thus, Kant insisted, the moral law must be the sole “fact of reason”—a fact that has no, but needs no, justification beyond the force with which it impresses itself on us (Kant 1999 [1788], 5:31, 5:47–8). Cohen thinks this was an inadequate justification of the moral law. He attempts to show that an improved justification results from transcendental reflection on the idea of a pure will, that is, the idea of a will that is not conditioned by any antecedent causes and is therefore free. With Kant, he argues that such a will is possible only on the condition that the moral law applies to it. But unlike Kant, he does not assert the actuality of a pure, free will. Rather, he argues that freedom of the will is itself a regulative ideal, an end at which we aim our actions (Cohen 1877, 199–201ff.).