When the first people started to argue against slavery, for example, this was a new idea. If you crowd-source, you'd never come up with this. And so the - exactly the kind of progress we've made couldn't be made if we depend it on crowd-sourcing.

It's very important to remember that the philosophers were social dissidents. They were social critics. The man in the street or woman in the street did not particularly cherish what they said. Socrates was killed.

If there is such a thing as philosophical progress, then why - unlike scientific progress - is it so invisible? Philosophical progress is invisible because it is incorporated into our points of view. What was torturously secured by complex argument comes widely shared intuition, so obvious that we forget its provenance.

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.

Everybody makes excuses for themselves they wouldn't be prepared to make for other people.

Paraphrasing Plato's Republic: "Only people who have allowed themselves to be reformed by reality have it in themselves to reform their polis for the better."

I think one reason is that philosophers are more insecure to speak accessibly because non-philosophers are skeptical that philosophers have any special expertise. After all, all people - not just philosophers - have attitudes and points of view on various philosophical questions, and they rather resent being told that there are professionals who can think about these things better.