In the academic setting, you take (typically) lonely, interesting middle-aged men and beautiful, intelligent young women, and everybody's motivations for display and conquest are engaged to the max. Sublimated, this can be a powerful force for the good - Plato had a lot to say about that - but acted upon it can bring evils without end.

It used to be that nobody would really argue with a woman, because what she thought (unless it was by way of providing helpful comments about one's own work) just didn't matter.

You can reasonably make the intellectual journey from thinking it's permissible to eat shrimp to thinking it's not permissible, or vice versa, whereas our slavery journey was uni-directional. We are as certain we are not going back to that old kind of slavery as we are that we aren't going back to the geocentric universe.

The (atomic) soul is mortal, and the best life is the one with the least pain and the most pleasure.

I had the idea that there were secret laws of the universe that could explain the baffling human reality around me, and that philosophers maybe had the key to them.

We call 'Slavery is wrong' a moral truth because there is a specific history of theoretical investigation of a particular kind of slavery. We discussed it for centuries in metaphysical, economic, biological, and philosophical terms; we listened to all the arguments pro and con, we read all the testimonies of slaves and witnesses, and we decided. Though this 'we" is not everybody on earth, or even most people, who've never thought about slavery much.

People should be able to develop their abilities and interests and have access to such goods as friendship, artistry, and nature and a political voice. It's possible to be poor and yet have all this, but in a polarized society, and one where culture and adventure have been thoroughly monetised, it is a lot more difficult.