Do you really believe that the moon isn’t there when nobody looks?

The devil has put a penalty on all things we enjoy in life. Either we suffer in our health, or we suffer in our soul, or we get fat.

You teach me baseball and I'll teach you relativity...No we must not. You will learn about relativity faster than I learn baseball.

Games are the most elevated form of investigation.

There is nothing divine about morality, it is a purely human affair.

It is also a natural thing for a serious young man that he should form for himself as precise an idea as possible of the goal of his desires.

Why does this magnificent applied science which saves work and makes life easier bring us so little happiness? ... The simple answer runs: 'Because we have not yet learned to make sensible use of it.'