Of course there are worlds. Millions of them! Every star you see has worlds, and most of those you don't see.

Science is a set of rules to keep us from telling lies to each other. All scientists really have is a reputation for telling the truth.

The world of A.D. 2014 will have few routine jobs that cannot be done better by some machine than by any human being. Mankind will therefore have become largely a race of machine tenders.

All evil is good become cancerous.

Surely, if we take on thinking partners - or, at the least, thinking servants - in the form of machines, we will be more comfortable with them, and will relate to them more easily, if they are shaped like humans. It will be easier to be friends with human-shaped robots than with specialized machines of unrecognizable shape. And I sometimes think that, in the desperate straits of humanity today, we would be grateful to have nonhuman friends, even if they are only the friends we build ourselves.

The Earth should not be cut up into hundreds of different sections, each inhabited by a self-defined segment of humanity that considers its own welfare and its own "national security" to be paramount above all other consideration.

To test a perfect theory with imperfect instruments did not impress the Greek philosophers as a valid way to gain knowledge.