5 Quotes by Paul Ehrenfest

Einstein, my upset stomach hates your theory [of General Relativity]—it almost hates you yourself! How am I to' provide for my students? What am I to answer to the philosophers?!!

Physics is simple, but subtle.

Don’t be impatient with me. Bear in mind that I hop around among all of you big beasts like a harmless and helpless frog who is afraid of being squashed.

No two electrons in the same state? That is why atoms are so unnecessarily big, and why metal and stone are so bulky.

You will get your difficulties with the point electron.