A model is done when nothing else can be taken out.

If we want to go to space with humans, that's for fun not for science. Human adventures in space are just sporting events.

New directions in science are launched by new tools much more often than by new concepts. The effect of a concept-driven revolution is to explain old things in new ways. The effect of a tool-driven revolution is to discover new things that have to be explained.

There are two different ways of looking at the universe; and it's the same universe with two different windows. The science window gives you a view of the world, and the religion window gives you a totally different view. You can't look at both of them at the same time, but they're both true.

There is nothing so big nor so crazy that one out of a million technological societies may not feel itself driven to do, provided it is physically possible.

The idea that global warming is the most important problem facing the world is total nonsense and is doing a lot of harm.

The average student emerges at the end of the Ph.D. program, already middle-aged, overspecialized, poorly prepared for the world outside, and almost unemployable except in a narrow area of specialization. Large numbers of students for whom the program is inappropriate are trapped in it, because the Ph.D. has become a union card required for entry into the scientific job market.