In this paper, I argue that Callicles has plausible reasons to accuse Socrates of playing word tricks around the notions of nature and convention. Whether Callicles is right or wrong to accuse Socrates of doing so is not the question here but how Plato makes us see by what Socrates and Callicles say the plausible reasons Callicles thinks he has to think he is right. At first, Socrates conventionally regards Callicles as an opponent worthy of engaging in dialectic. As his way of doing philosophy fails to engage Callicles, however, it naturally reveals that Socrates thinks otherwise of Callicles than what he conventionally said. To substantiate this thesis, I will focus extensively on Callicles’ Great Speech and Socrates’ short speeches before and after it.