Abstract
While there is good reason to think that Mendelssohn's Morgenstunden targets some of the key claims of Kant’s first Critique, this criticism has yet to be considered in the appropriate context or presented in all of its systematic detail. I show that far from being an isolated assault, Mendelssohn’s attack in the Morgenstunden is a continuation and development of his earlier criticism of Kant’s idealism as presented in the Inaugural Dissertation. I also show that Mendelssohn’s objection was more influential on Kant than has previously been suspected; not only did Kant respond to it in a brief review and a set of remarks published along with a disciple’s examination of Mendelssohn’s text but, as I will suggest, Kant’s Refutation of Idealism is intended (at least in part) to undermine the Cartesian starting-point Mendelssohn had presumed throughout his campaign against Kantian idealism.