Mathematics are well and good but Nature keeps dragging us around by the nose.

I never think of the future. It comes soon enough. When visiting the U.S. from Germany for a winter academic stay.

He who can no longer pause to wonder and stand rapt in awe, is as good as dead; his eyes are closed.

As soon as science has emerged from its initial stages, theoretical advances are no longer achieved merely by a process of arrangement. Guided by empirical data, the investigator rather develops a system of thought which, in general, is built up logically from a small number of fundamental assumptions, the so-called axioms. We call such a system of thought a theory. The theory finds the justification for its existence in the fact that it correlates a large number of single observations, and it is just here that the 'truth' of the theory lies.

The scientist finds his reward in what Henri Poincare calls the joy of comprehension, and not in the possibility of application to which any discovery may lead.

The majority of the stupid is invincible and guaranteed for all time. The terror of their tyranny, however, is alleviated by their lack of consistency.

The mind that opens to a new idea never returns to its original size