This paper analyzes Salomon Maimon’s commentary on Kant’s attempt to link sensibility and understanding. In the Critique of Pure Reason, Kant marks out two faculties of knowledge, which must be united in order to make objective knowledge possible. Maimon doubts that the connection is feasible. After discussing Kant’s starting point, the paper analyzes Maimon’s arguments, laying out the systematic difficulties which would affect the intent of Kantian unification.