Overview

In the ‘Analytic of Pure Practical Reason,’ Book I of the second Critique, Kant undertakes to show that ‘pure reason can be practical – that is, can of itself, independently of anything empirical, determine the will’ (5:42, 4). In the context of this demonstration, Sections 4–6 are primarily concerned with the second, third, and fourth steps in an ultimately seven-part argument (with the concepts of pure form, universal legislation, and transcendental freedom, respectively). Since these sections briefly repeat the first step (the exclusion of ‘material principles’) and effectively anticipate the fifth, sixth, and seventh steps of the overall argument (the ‘fundamental law,’ the ‘fact of reason,’ and the concept of ‘autonomy,’ respectively), they constitute the essential core of the ‘Analytic’ that introduces the second Critique.

According to the initial definition that opens Section I (5:19), the argument must establish the existence not merely of subjective principles (‘maxims’) but also of objective practical principles (‘practical laws’) that can properly be recognised as ‘holding for the will of every rational being’ (ibid.). For only then, as Kant points out in the ‘Remark’ that follows, can pure reason be said to ‘contain within itself a practical ground, that is, one sufficient to determine the will’ (ibid.).