Scientists must use the simplest means of arriving at their results and exclude everything not perceived by the senses.

Personally, people know themselves very poorly.

Strange as it may sound, the power of mathematics rests on its evasion of all unnecessary thought and on its wonderful saving of mental operations.

Bodies do not produce sensations, but complexes of elements (complexes of sensations) make up bodies.

In reality, the law always contains less than the fact itself, because it does not reproduce the fact as a whole but only in that aspect of it which is important for us, the rest being intentionally or from necessity omitted.

Many an article that I myself penned twenty years ago impresses me now as something quite foreign to myself.

I can accept the theory of relativity as little as I can accept the existence of atoms and other such dogmas.