Sometimes we talked about the nature of the human soul and about the Cosmic Unity of souls that I had believed in so firmly when I was 15 years old. My mother did not like the phrase Cosmic Unity. It was too pretentious. She preferred to call it a world soul.

It is better to be wrong than to be vague.

I think it's much better to have your eyes open, but on the other hand, of course it can do harm if you tell people look, there's all these terrible things you can do and then some idiot may go ahead and do it.

It is characteristic of all deep human problems that they are not to be approached without some humor and some bewilderment.

I think that the artificial-intelligence people are making a lot of noise recently, claiming that artificial intelligence is making huge progress and we're going to be outstripped by the machines.

We simply don't know yet what's going to happen to the carbon in the atmosphere.

Ethical progress is the only cure for the damage done by scientific progress.