I was trained as a philosopher never to put philosophers and their ideas into historical contexts, since historical context has nothing to do with the validity of the philosopher's positions. I agree that assessing validity and contextualizing historically are two entirely distinct matters and not to be confused with one another. And yet that firm distinction doesn't lead me to endorse the usual way in which history of philosophy is presented.

The sum and substance of education is the right training that effectually leads the soul of the child at play on to the love of the calling in its adult life.

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.

Youth is not an essential, but rather an accidental property. Nobody is in essence young. One either ceases to be or ceases to be young.

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.

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.

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.