The physicists have known sin; and this is a knowledge which they cannot lose.

There is something irreversible about acquiring knowledge; and the simulation of the search for it differs in a most profound way from the reality.

Truth, not a pet, is man's best friend.

There must be no barriers for freedom of inquiry... There is no place for dogma in science. The scientist is free, and must be free to ask any question, to doubt any assertion, to seek for any evidence, to correct any errors.

The most beautiful philosophical song existing in any known tongue.

The history of science is rich in example of the fruitfulness of bringing two sets of techniques, two sets of ideas, developed in separate contexts for the pursuit of new truth, into touch with one another.

When all thermonuclear sources of energy are exhausted a sufficiently heavy star will collapse. Unless fission due to rotation, the radiation of mass, or the blowing off of mass by radiation, reduce the star's mass to the order of that of the sun, this contraction will continue indefinitely.