I argue that, by the time of his essay "Concerning the Ultimate Ground of the Differentiation of Directions in Space" (1768), Kant had come to question the status of the Principle of Sufficient Reason as a result, at least in part, of his recognition of the existence of incongruent counterparts. Though Kant's argument against absolute space based on the existence of incongruent counterparts has been much discussed in recent years, its importance as a useful benchmark by which to judge the (...) direction of Kant’s thinking during this period has gone unnoticed. This paper is a modest attempt to remedy this deficiency. (shrink)