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.

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.

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.

We have to gamble, and sometimes lose as George Ainslie argues; this keeps the appetite for life sharp.

For the chemists, who wanted to manufacture new medicines and elixirs and transform base substances into noble ones, the notion that there was no metaphysical barrier to doing so - it was just a matter of getting the particles into new arrangements - was encouraging. That was the Baconian programme.

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.