Many of the things you can count, don't count. Many of the things you can't count, really count.

If you want your children to be intelligent, read them fairy tales. If you want them to be more intelligent, read them more fairy tales.

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

We scientists, whose tragic destination has been to help in making the methods of annihilation more gruesome and more effective, must consider it our solemn and transcendent duty to do all in our power in preventing these weapons from being used for the brutal purpose for which they were invented.

Strenuous intellectual work and the study of God's Nature are the angels that will lead me through all the troubles of this life with consolation, strength, and uncompromising rigor.

Development of Western science is based on two great achievements: the invention of the formal logical system (in Euclidean geometry) by the Greek philosophers, and the discovery of the possibility to find out causal relationships by systematic experiment (during the Renaissance). In my opinion, one has not to be astonished that the Chinese sages have not made these steps. The astonishing thing is that these discoveries were made at all.

I have repeatedly said that in my opinion the idea of a personal God is a childlike one.