Heraclitean flux plays a large role in Plato 's « Theaetetus » and « Cratylus ». Yet Heraclitus himself did not hold the same conception of flux. The question of how the two thinkers differ, and why Plato treats Heraclitus as he does, is significant because the notion of flux has figured in subsequent philosophical conceptions of the persistence of identity through change. Comparison of Heraclitus, frr. B 12 and B 125 DK reveals that flux is not motion simply, but (...) motion productive of stability ; the unity of stability and flux is the « unapparent connection » that it is Heraclitus ' mission to reveal. Analysis of Tht. 179 C-181 B and Cra. 402 A 3-8 and 411 B-C shows neither any exegesis of Heraclitus ' words, nor any evidence that Plato has in mind any historical Heracliteans. The playful way in which Plato handles Heracliteanism, with comic and hyperbolic imagery, suggests that his audience would have recognized Heraclitean flux as a familiar theory from the context of contemporary oral dialectic. (shrink)