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 worried that philosophical writing would take the place of living conversations for which, in philosophy, there is no substitute.

God doesn't help. I think that's a knockdown argument. I think that it really shows that whatever moral knowledge we have and whatever moral progress we make in our knowledge or whatever progress we make in our moral knowledge is not coming really from religion. It's coming from the very hard work really of moral philosophy, of trying to ground our moral reasonings.

Everybody is struggling to refine their views in opposition to the other people. And that's one of the most important things that philosophy actually has to teach us that you have to air your views and bring them to the table with people - with whom you disagree very much.

In Greek, our word for play is paidia and the word for education is paideia, and it is very natural and right that these words should be entangled at the root, together with our word for children, paides, which gave you your words pedagogy and pediatrician.

What is love? When you love somebody then I mean we all want good things to happen to ourselves and keep the bad things at bay. When you love somebody you want that as much for them if not more than you do for yourself.

I don't think I can write the story of my life, but I can write the story of my hair.