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.

There's Hobbes, who understood in the 1640s that the sovereign is not an appointee of God, or even a figure of superior virtue and wisdom, but just a functional device whose role is to keep people from hurting and killing each other.

Epicurus was not at all interested in what we would call the problems of mass society, and he thought civic politics was just trouble and to be avoided by the wise.

Morality has in the past made progress when we broadened the category of things we weren't permitted to harm (animals, 'infidels'); saw through some delusions and rationalisations about what harms are good for people themselves (prison punishment, hysterectomies for unhappy 1950s wives); and readjusted our for-the-good of others criteria so as to demand only reasonable sacrifices (ceasing to use children as handy chimney sweeps).

A moral rule is essentially 'advantage-reducing.' It prohibits you doing something you could do that would serve your interests at someone else's expense.

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

Highly unequal societies are morally defective because they get to be that way through the exploitation by the clever and well-positioned ones of the vulnerabilities and weaknesses of others. The well-off then use their acquired political power to refuse to make sacrifices for others. This system brings us a wonderful range of products and experiences for consumers at the top of the privilege scale, but it also degrades and benumbs the workers at the lower end, as Adam Smith and Marx both said.