In the so-called ‘dialogues of definition,’ Socrates appears to endorse the ‘priority of definition.’ This principle states that an agent cannot know anything about F-ness (its instances, examples, properties, etc.) without knowing what F-ness is (the definition of F-ness). Not only is this principle implausible, it is also difficult to square with Socrates’ method. In employing his method, Socrates appeals to truths about the instances and properties of F-ness, even while pursuing definitional knowledge; meanwhile, he holds that one cannot know (...) those truths without already knowing the definition. Thus, there is a tension between Socrates’ principle and his method. Commentators have tried to resolve this problem in various ways, though typically without a careful examination of his ‘What is F-ness?’ question. I argue that Socrates employs the ‘What is F-ness?’ question as a way of introducing two distinct types of investigation into F-ness (conceptual and causal). With this established, the relationship between Socrates’ principle and his method comes to light, and the tension is resolved. (shrink)