The Deductions of Freedom / Morality-as-Autonomy and the Categorical Imperative in Groundwork III and Their Problems

The first objective of this paper is to present an interpretation of Groundwork III which aims to establish two main points: first, that Kant offers there a theoretically-grounded deduction (in Kantian sense) of freedom/morality-as-autonomy; second, that Kant also offers a separate deduction of the categorical imperative. Thus, contrary to what several commentators have claimed, Groundwork III contains a theoretically-grounded double deduction. The second objective of the paper is to examine and criticize in detail one crucial step in these deductions, namely, Kant’s inference from the speculative spontaneity of reason to the noumenal existence of the subject as a free will. I show that Kant himself came to reject this inference in the B edition of the Critique of Pure Reason, and argue that this explains Kant’s rejection, in the Critique of Practical Reason, of the deduction of the moral law he previously offered. Thus, contrary to the “reconciliationist” reading, there is indeed a great reversal in the latter work.

1 What is a Kantian deduction? -- 2 The deductions of freedom/morality-as-autonomy and the categorical imperative in Groundwork III -- 2.1 The moral law as a synthetic a priori proposition -- 2.2 The deductions, step one: linking rationality and autonomy -- 2.3 The deductions, step two: the intelligible world and the deduction of freedom -- 2.4 Interlude: the circle -- 2.5 The deductions, step three: the production of ideas and the spontaneity of reason -- 2.6 The deductions, step four: the deduction of the categorical imperative -- 3 Two problems with the deduction of freedom/morality-as-autonomy in Groundwork III -- 3.1 Kantian ideas: speculative and practical -- 3.2 Speculative ideas and freedom of the will -- 3.3 Spontaneity of reason and the self as noumenon -- Conclusion