It is not unscientific to make a guess, although many people who are not in science think it is.

Religion is a culture of faith; science is a culture of doubt.

There is enough energy in a single cubic meter of space to boil all the oceans in the world.

We are at the very beginning of time for the human race. It is not unreasonable that we grapple with problems. But there are tens of thousands of years in the future. Our responsibility is to do what we can, learn what we can, improve the solutions, and pass them on.

When the problem [quantum chromodynamics] is finally solved, it will all be by imagination. Then there will be some big thing about the great way it was done. But it's simple -it will all be by imagination, and persistence.

Although it is uncertain, it is necessary to make science useful. Science is only useful if it tells you about some experiment that has not been done; it is not good if it only tells you what just went on.

Just as a poet often has license from the rules of grammar and pronunciation, we should like to ask for 'physicists' license from the rules of mathematics in order to express what we wish to say in as simple a manner as possible.