Once I even took the train to Utrecht, forty miles from Amsterdam, with my yellow star, this star which I still have. Why did I go? I just wanted to visit some friends. I was a little bit crazy, a little bit insane.

Of course, relative citation frequencies are no measure of relative importance. Who has not aspired to write a paper so fundamental that very soon it is known to everyone and cited by no one?

There is not a soul on Earth who can read the deluge of physics publications in its entirety. As a result, it is sad but true that physics has irretrievably fallen apart from a cohesive to a fragmented discipline. ... It was not that long ago that people were complaining about two cultures. If we only had it that good. today.

Some years ago John Kenneth Galbraith wrote in an essay on his efforts at writing a history of economics: 'As one approaches the present, one is filled with a sense of hopelessness; in a year and possibly even a month, there is now more economic comment in the supposedly serious literature than survives from the whole of the thousand years commonly denominated as the Middle Ages ... anyone who claims to be familiar with it all is a confessing liar.' I believe that all physicists would subscribe to the same sentiments regarding their own professional literature. I do at any rate.

I spent every night until four in the morning on my dissertation, until I came to the point when I could not write another word, not even the next letter. I went to bed. Eight o'clock the next morning I was up writing again.

To make a discovery is not necessarily the same as to understand a discovery. Not only Planck but also other physicists were intially at a loss as to what the proper context of the new postulate really was.

The rule of the game was never assume that anybody, however honorable, would be able to stand up under torture. If Mr. X, who knew where I was, was caught for some reason, I should move.