A Guide to Ground in Kant’sLectures on Metaphysics

The Principle of Sufficient Reason (PSR) says that everything has a reason that fully explains it. Leibniz expresses the PSR in Latin and French, respectively, as the principle that everything has a ratio or raison. When German philosophers of the eighteenth century, heavily influenced by the Leibnizian writings available to them, formulated similar ideas in their native tongue, they translated ratio as Grund and expressed the PSR accordingly as: Everything has a ground that fully explains it. This Principle of Sufficient Ground (Satz des zureichenden Grundes) or PSG is, so to speak, the Leibnizian PSR translated into German. The PSG – how to correctly formulate it, whether it holds without restriction – became one of the major topics of debate within the Leibnizian tradition of late eighteenth-century German philosophy, commonly known as German rationalism. It comes as no surprise then that Kant, steeped as he was in German rationalism and its debates, would extensively discuss the PSG and the notion of ground (Grund) in the metaphysics lectures he gave virtually every semester at the University of Königsberg from 1755 until his retirement from teaching in 1796. Nearly every extant transcript of those lectures contains extended discussions of the correct definition of “ground,” critical comments on the views of his near contemporaries (especially those of Wolff, Baumgarten and Crusius) about what grounds are, distinctions among different kinds of ground and considerations about the correct formulation and range of application of the PSG. While scholars have extensively discussed Kant’s treatment of the PSG in the Antinomies chapter of the Critique of Pure Reason, and, more