  In the early dialogues, Socrates seeks these ethical universals through a distinctive mode of inquiry, the  ‘elenchus’ (see Vlastos 1992; Kraut 1983).  Elenctic inquiry is fundamentally a form of cross-examination, where Socrates tries to elicit from others their beliefs about matters of justice or piety, etc. Typically the result is that his interlocutors turn out to have an inconsistent set of beliefs about the virtues. At the heart of the Socratic elenchus is the ‘What is X’ question (where ‘X’ typically names an ethical property). The answers offered to these questions fail usually because they are too narrow or too wide. An answer is too narrow if it fails to include all cases. An answer is too wide if, while it includes all cases of, for instance, piety, it also includes other things, cases of justice or impiety. We can infer from these failed definitions a set of conditions Socrates places on an adequate answer to his ‘What is X’ questions. He is seeking an answer which picks out a Socratic Property, e.g., Piety, that is a universal such that: it is found whenever and wherever there is an instance of Piety; and it ‘causes’ or ‘makes’ the instance to be such as it is. Piety's power to make, e.g., Socrates, pious derives from Piety's itself being pious. Piety self-predicates: Piety is pious. Because it is pious, when Piety is present to/in Socrates, Piety causes Socrates to be pious. In the Socratic dialogues Plato does not distinguish the (metaphysical) way in which Socrates is pious from the way in which Piety is pious—in these dialogues there appears to be just one ontological predication relation. One has knowledge of a Socratic Property when she can give an account (logos) that says what X is, that is, when she can give the definition of the property under investigation. Treating a definition as a linguistic item, we can say that the definition specifies or picks out the essence (ousia) of the property, and a definitional statement predicates the essence of the property whose essence it is. It is unclear from the Socratic dialogues whether any other property is predicated of a Socratic Property: arguably Piety is pious and only pious. In contrast, the things that are pious, e.g., Socrates or saying a prayer, have many properties. From what we can infer from Plato's remarks in these early dialogues, and from Aristotle's remarks, a Socratic property is in the sensibles—It is an immanent universal. In this respect, the essence of Piety is also found in Socrates (and thus the linguistic definition of Piety is also linguistically predicable of Socrates). Plato's distinctive ‘separation of the universal’ might then be viewed as his rejection of Socrates' assumption that the universal (and/or its essence) is in the sensibles, (and accordingly a rejection of Socrates' assumption that the definition is predicable, or predicable in the same way, of the sensible instances as well as the universal.) If Aristotle is right, Plato's problem with sensibles is that they change.