Eight years ago, I drew up a template to use to take notes on each Plato dialog. The template begins with a line for the subject: piety in the case of Euthyphro, justice for The Republic, and so on. The next section of the template lists the characters in the dialog. And then comes the situation: Socrates is at a dinner party with a Sophist, or Socrates is in prison awaiting his trial. At first, my template went next straight to a list of successive definitions of the topic at hand, the usual structural outline of the dialogs. But after taking notes on the first two or three, I decided I needed a new section, which I labeled for myself, “Shared assumptions (one must have some idea of the subject in order to pursue its definition!).” How can Socrates begin to define justice or knowledge without everyone having some idea what it is to begin with? As Wittgenstein put it, how can your friend answer the question “What is that?” unless you’re pointing at a “that” and he’s looking at the same “that”? You might not either one know what “that” is, but at least you both know which mysterious “that” it is that you can’t identify.
So I was very pleased to open up the Sophist and find Plato making the very point on the second page. The Eleatic Stranger (more about him next time) wants to define the Sophist, but he and his dialog partners have to be able first to identify Sophists, if only by name, so they know what profession it is that they’re defining. “You and I,” he says, “will begin together and inquire into the nature of the Sophist . . . . I should like you to make out what he is and bring him to light in a discussion; for at present we are only agreed about the name, but of the thing to which we both apply the name possibly you have one notion and I another.” Later on, they agree that Sophists are those people who say that no one can ever speak a falsehood, because saying a lie has been spoken involves asserting being of non-being. But then they have to begin the search for a definition. Is this person a teacher? A salesman? A hunter of gullible souls? An impersonator? An entertainer?
As I read and thought about this problem, I also thought about Aristotle’s Topics, in which he says that in a good, effective sentence, the predicate must be clearer than the subject. Take the sentence, “A cow has four stomachs.” And imagine an eight-year-old hearing this information for the first time. She learns something she didn’t know before. She already knows what a stomach does, and she knows from before how many four are, but she has not known that the cow has four stomachs. The sentence teaches this girl, because to her the predicate is clearer than the subject. But if she had an unclear notion of the subject, how could she really even know what the sentence was about? Because her notion was clear enough. She had a picture, a set of mental associations with the word cow. She had a sense of that-ness long before anyone ever tried to define the cow.