This essay shows that Derrida's discussion of "Differance," is remarkably parallel to Plato's discussion of Difference in the Parmenides. Plato's presentation of "Parmenides'" discussion of generation from a One which Is is a version of Derrida's preconceptual spacing. Derrida's implicit reference to Plato both interprets Plato and explains the obscure features of "Differance." Derrida's paradoxical remarks about Differance are very like what Plato implies about Difference. Derrida's Differance addresses the puzzle that concepts are required to construct the beings in a (...) plurality of objects, but concepts cannot differentiate unless there is already a plurality of objects. Plato's version of the same problem is a notational variant of Derrida's Husserlian dilemma. Derrida, following Davidson, is not only skeptical about the project of founding metaphysics on simple entities, but also holds that necessity has no foundation in the "world." Plato, on the other hand, retains the idea that necessity has an objective basis in the self-evident truths of mereology. (shrink)