When things are going well, something will go wrong. / When things just can't get any worse, they will. / Anytime things appear to be going better, you have overlooked something.

Experiment is the sole judge of the validity of any idea.

Another thing I must point out is that you cannot prove a vague theory wrong.

It doesn't seem to me that this fantastically marvelous universe, this tremendous range of time and space and different kinds of animals, and all the different planets, and all these atoms with all their motions, and so on, all this complicated thing can merely be a stage so that God can watch human beings struggle for good and evil - which is the view that religion has. The stage is too big for the drama.

The first principle is that you must not fool yourself and you are the easiest person to fool.

In fact the total amount that a physicist knows is very little. He has only to remember the rules to get him from one place to another and he is all right.

But logic is not all, one needs one's heart to follow an idea.