  What is that one thing still missing? As the discussion proceeds, the Stranger argues that we are missing the feature of sophists that explains how they can successfully appear wise to their students, when they are not in fact wise (Sophist 233b–c). He and Theaetetus carefully defined the sophist in terms of many of his activities but none of those makes him what he is. They have so far missed the essence of the sophist, and for that reason they mistakenly call him by many names instead of one.