The Duisburg Nachlaß is a bundle of Kant’s handwritten notes. These notes almost certainly go back to some time in 1775. Though very obscure, they replay issues in Kant’s early metaphysics just as clearly as they anticipate issues in the Critique of Pure Reason. This makes them an important way-station in Kant’s philosophical development—all the more important, because he published nothing in the 1770s and left no other extended writings in his own hand. A proper understanding of the Duisburg Nachlaß (...) might therefore explain some of Kant’s later ideas: their origins in his earlier thinking and their philosophical motivations. The purpose of this paper is to lay the groundwork for such an explanation—at least a partial one. I shall argue that Kant’s efforts in the Duisburg Nachlaß to correct certain difficulties in the Inaugural Dissertation of 1770 anticipate and naturally lead to the crucial claim in the Critique of Pure Reason that the understanding legislates laws to nature. (shrink)