,,[...] wollen wir den Begriff der Pflicht vor uns nehmen [...]". Die vier ersten der ,drei Sätze' in Grundlegung I (04:397–400)

In the first section of the Groundwork, Kant claims that his definition of "duty" follows as a consequence ("Folgerung") from two antecedent propositions - but he only makes the "second" one explicit. Over the last seventy years, scholars have tried without success to pinpoint Kant's "first proposition". This paper uncovers the first proposition in the text, establishes the validity of the "consequence", and shows its importance for the argument of the book as a whole.