The only mistake in life is the lesson not learned.

Applying the axioms of physical science to human life has something reprehensible to it.

Persistence is the most powerful force on earth, it can move mountains.

I believe in Spinoza's God, who reveals Himself in the lawful harmony of the world, not in a God who concerns Himself with the fate and the doings of mankind... to Rabbi Herbert Goldstein (1929)

A man's moral worth is not measured by what his religious beliefs are but rather by what emotional impulses he has received from Nature during his lifetime.

If [quantum theory] is correct, it signifies the end of physics as a science.

If at first the idea is not absurd, then there is no hope for it.