We can, for example, be fairly confident that either there will be a world without war or there won't be a world - at least, a world inhabited by creatures other than bacteria and beetles, with some scattering of others.

Telling us to obey instinct is like telling us to obey 'people.' People say different things: so do instincts. Our instincts are at war... Each instinct, if you listen to it, will claim to be gratified at the expense of the rest.

Liberty, taking the word in its concrete sense, consists in the ability to choose.

I'm an optimist in the sense that I believe humans are noble and honorable, and some of them are really smart. I have a very optimistic view of individuals.

Revolutionaries do not make revolutions. The revolutionaries are those who know when power is lying in the street and then they can pick it up.