Find more pleasure in intelligent dissent than in passive agreement, for, if you value intelligence as you should, the former implies a deeper agreement than the latter.

It seems to me a fundamental dishonesty, and a fundamental treachery to intellectual integrity to hold a belief because you think it's useful and not because you think it's true.

Order, unity, and continuity are human inventions, just as truly as catalogues and encyclopedias.

Physics, owing to the simplicity of its subject matter, has reached a higher state of development than any other science.

To save the world requires faith and courage: faith in reason, and courage to proclaim what reason shows to be true.

The use of self control is like the use of brakes on train. It is useful when you find yourself in wrong direction but merely harmful when the direction is right

The more intense has been the religion of any period and the more profound has been the dogmatic belief, the greater has been the cruelty and the worse has been the state of affairs.