Abstract

I draw attention to a 12-page Vorarbeit to Kant’s Prolegomena from the so-called Scheffner-Nachlaß and argue that the parallel Kant draws there between the possibility of theoretical and practical synthetic a priori propositions provides important insight into the development of his account of practical autonomy in the Groundwork. Based on a brief sketch of the role synthetic a priori propositions play in the development of Kant’s critical philosophy, I conclude that for Kant the objective validity of any science depends on the objective validity of a number of synthetic a priori propositions.