And what is it, according to Plato, that philosophy is supposed to do? Nothing less than to render violence to our sense of ourselves and our world, our sense of ourselves in the world.

One of the interesting things about the ancient Greeks is that they really didn't have our conception of individual rights. They didn't have our conception of all lives matters. And it was really was true for them, that certain lives matter a lot more than others. It didn't dawn on them that all lives, although different, can be lives of equal mattering. And that is actually something a huge ethical lesson.

Plato dramatically puts the detachment of the philosopher from his time this way: to philosophize is to prepare to die.

So Socrates was a kind of gadfly. He was a sort of philosophical urban gorilla hanging around in the middle of Athens, asking these peculiar questions of everybody - important people, young men, slaves - questions that had to do with ultimately what's the life that's worth living. And Plato was one of the young men who hung around him, a very aristocratic young man, came from a very old, important family.

Plato conceived of philosophy as necessarily gregarious rather than solitary. The exposure of presumptions is best done in company, the more argumentative the better.

If we don't understand our tools, then there is a danger we will become the tool of our tools. We think of ourselves as Google's customers, but really we're its products.

If you don't exert yourself, or if your exertions don't amount to much of anything, then you might as well not have bothered to have shown up for your existence at all.