Kant had carefully studied some central texts of Leibniz, including the Monadology (in its Latin translation as Principia philosophiae),the Theodicy,the New Essays on Human Understanding and the correspondence with Clarke.⁸² Kant himself possessed a definite hermeneutic attitude in his reading of previous thinkers. So we find that not only did he claim to understand Plato's thought better than Plato himself did,⁸³ but he says the same about Leibniz. At the end of his interpretation of Leibniz in On a Discovery According to which Any New Critique of Pure Reason Has Been Made Superfluous by an Earlier One, Kant denounces historians of philosophy who "neglect the key to the interpretation […] They are thus incapable of recognizing beyond what the philosophers actually said, what they really meant to say."⁸⁴ Let these words serve as a caveat. The present study focuses upon Kant's interpretation and transformation of Leibniz's principle of sufficient reason culminating in the Critique of Pure Reason. Reading Leibniz purely for his own sake would be a different project. Before we listen to Kant, however, let us bring Leibniz himself before us in his words from the Monadology and Theodicy: