A single part of physics occupies the lives of many men, and often leaves them dying in uncertainty.
Physics is mathematical, not because we know so much about the physical world, but because we know so little: it is only its mathematical properties that we can discover.
People like us, who believe in physics, know that the distinction between past, present, and future is only a stubbornly persistent illusion.[Sometimes misquoted as:]Reality is merely an illusion, albeit a very persistent one.
If I were not a physicist, I would probably be a musician. I often think in music. I live my daydreams in music. I see my life in terms of music. … I cannot tell if I would have done any creative work of importance in music, but I do know that I get most joy in life out of my violin.
Fundamental ideas play the most essential role in forming a physical theory. Books on physics are full of complicated mathematical formulae. But thought and ideas, not formulae, are the beginning of every physical theory. The ideas must later take the mathematical form of a quantitative theory, to make possible the comparison with experiment.