Locke and Leibniz are often classified as proponents of compatibilist theories of human freedom, since both maintain that freedom is consistent with determinism and that the difference between being and not being free turns on how one is determined. However, we will argue in this paper that their versions of compatibilism are essentially different and that they have significantly distinct commitments to compatibilism. To this end, we will first analyze the definitions and examples for freedom and necessity that Locke and (...) Leibniz present in sections 8-13 of chapter 21 of the Essay on Human Understanding and the Nouveaux essais respectively, and then conjecture how Locke and Leibniz would have continued the discussion, if they had had the opportunity to engage in an exchange of opinions. In this way, we believe, one will be in a position to understand why Leibniz thinks that Locke’s discussion of freedom “est un des plus prolixes et des plus subtils de son ouvrage.”. (shrink)