Einstein does not remain attached to the classical principles, and when presented with a problem in physics he quickly envisages all of its possibilities. This leads immediately in his mind to the prediction of new phenomena which may one day be verified by experiment.

One does not ask whether a scientific theory is true, but only whether it is convenient.

Doubting everything and believing everything are two equally convenient solutions that guard us from having to think

All great progress takes place when two sciences come together, and when their resemblance proclaims itself, despite the apparent disparity of their substance.

Experiment is the sole source of truth. It alone can teach us something new; it alone can give us certainty.

A scientist worthy of his name, about all a mathematician, experiences in his work the same impression as an artist; his pleasure is as great and of the same nature.

Thought is only a flash between two long nights, but this flash is everything.