We should take care not to make the intellect our god; it has, of course, powerful muscles, but no personality.

A theory is the more impressive the greater the simplicity of its premises is, the more different kinds of things it relates, and the more extended is its area of applicability. Therefore the deep impression which classical thermodynamics made upon me. It is the only physical theory of universal content concerning which I am convinced that within the framework of the applicability of its basic concepts, it will never be overthrown.

Beyond the realms of what we see, into the regions or the unexplored limited only by our imaginations.

I know that philosophically a murderer is not responsible for his crime, but I prefer not to take tea with him.

It is nothing short of a miracle that modern methods of teaching have not yet entirely strangled that sacred spirit of curiosity and inquiry, for this delicate plant needs freedom no less than stimulation.

Whatever your problems in math are, I assure mine are greater.

Belief in an external world independent of the perceiving subject is the basis of all natural science.