Man would indeeded be in a poor way if he had to be restrained by fear of punishment and hope of reward after death.

A happy man is too satisfied with the present to dwell too much on the future.

Between the difficulties, one hides the opportunity

A theory is something nobody believes, except the person who made it. An experiment is something everybody believes, except the person who made it.

When a man points a finger at someone else, he should remember that three of his fingers are pointing at himself. Do not worry about your difficulties in mathematics; I can assure you that mine are still greater.

We should be on our guard not to overestimate science and scientific methods when it is a question of human problems, and we should not assume that experts are the only ones who have the right to express themselves on questions affecting the organization of society.

Now to the term 'relativity theory.' I admit that it is unfortunate, and has given occasion to philosophical misunderstandings.