We talked about four questions:
Philosophers should rule because they know what is good. They both have the inclination to learn about what is really good and the ability to discover the answer. The other members of the city have neither the inclination nor the ability to know the good.
But what is this really good or “the” good of which Plato speaks?
The answer to that question took us on an extensive discussion of Plato’s doctrine of the forms and, in particular, the form of the good. Forms are what explain why particular things have the qualities that they do, such that otherwise diverse things could all be brown, beautiful, rectangular, or good. Philosophers are interested in forms. Unlike other people, they are not content to have a lot of knowledge of particular things that they get through their everyday experience of the world: “the many beautiful things are visible but not intelligible, while the forms are intelligible but not visible” (507b).
I used analogies to our understanding of the sciences in order to illustrate the sort of thing that Plato meant. Roughly, we think that the laws of physics and the entities that are mentioned in those laws best describe ultimate reality. Their description of ultimate reality is quite different from everyday experience: tables aren’t actually solid, for instance. But we still believe that what physicists tell us about tables is more accurate than what our eyes tell us.
There two big difference between our scientific image of the world and Plato’s.
First, as Will pointed out, scientific knowledge is based on sensory experiences. We devise experiments and instruments that enable us to extend what we can learn by the senses beyond what we gain from everyday experience. But it all comes down to experience nonetheless. For Plato, by contrast, mathematics provided the model of knowledge. But mathematics has nothing to do with anything particular that you can see or touch. When we draw figures like my right triangle, it’s just a way of saying “we’re talking about right triangles now.” It doesn’t mean that we’re going to say anything about the particular figure on the board: after all, it’s unlikely to be a genuine right triangle.
Second, Plato believed that values, such as the good, are part of ultimate reality. The abstract study of these forms will reveal not only the laws governing physical bodies but what is good, beautiful, and the like. This is foreign to our belief that ultimate reality is best studied through the natural sciences.
Going back to rule the city seems to be bad for the philosophers. Why would they do it? I said that I thought there were two broad kinds of answers in the Republic.
There are advantages and disadvantages to each of these answers.
The first answer would explain why they would do it. But it isn’t informative: why is this is the just thing to do and how do they know that? And if this is why they would do it, what are we doing about Glaucon’s question? Wasn’t the challenge to show why it makes sense to sacrifice your own interests for the sake of others when you don’t have to do so? How does the claim that the philosophers will sacrifice their own interests for the sake of others because it’s the just thing to do help to meet that challenge? Is it because we assume they know more about what is good than we do, such that they would know the answer even if we don’t? Perhaps, but that doesn’t tell us much about what the answer to Glaucon’s question is.
Maybe Glaucon’s question was answered in Book IV, as Sam suggested. That makes a lot of sense to me. But this seems like a perfect occasion to apply the answer from Book IV to a particular question. How would that answer have gone?
The second answer is given by Williams at the end of the handout. It is more informative. But it faces two difficulties of its own. First, it appears to fall short of showing that justice is desirable “for its own sake.” At most, it seems to show that the guardians have to think of it that way for the sake of the philosophical life that they value. It also raises a question about why any individual philosopher would be willing to rule. If I’m a philosopher, my best option would be for other philosophers to rule the city, leaving me free to walk around outside the cave. Of course, the other philosophers probably won’t let me get away with that. But actually ruling seems to be a distinctly second best alternative, just as Glaucon said just behavior in general is.
The term “compulsion” is used in two different senses in our translation. The ambiguity almost certainly pervades the original greek text as well.
When Plato says that the study of mathematics “compels the soul to use understanding itself” (526b), he means that the force of reasoning will lead to this outcome. Anyone who understands mathematics will think in this way (whatever it means to “use understanding itself”).
By contrast, when he describes the oligarchic person as holding his appetites in check “not by persuading them that it’s better not to act on them or taming them with arguments, but by compulsion and fear” (554d), he means something quite different. “Compulsion” here involves force, not persuasion.
Plato says that the philosophers will “go to rule as to something compulsory” (520e). Which sense does he mean there? I think that most scholars believe it is the first one: they go to rule because they are convinced that it is the right thing to do.