In an interview for the Yorkshire Television program Take the World from Another Point of View (1972), Richard Feynman said:

You see, I have had in my life a number of pleasant experiences. One of the earliest ones was when I was a kid I invented a problem for myself, the sum of the powers of the integers, and in trying to get the formula for it I developed a certain set of numbers, the formula for which I couldn’t get, and I discovered later that those were known as the Bernoulli numbers and discovered in 1739. So I was up to 1739 when I was about 14 you see. And then a little later I discovered something that I’d find out I just may have invented a thing which we now call operator calculus. That was invented in 1890-something. Gradually I was inventing things that came later and later.

But the moment when I began to realize that I was now working on something new was when I read about quantum electrodynamics at the time and I read a book, and I learned about it. For example, I read Dirac’s book, and he had these problems that nobody knew how to solve that were described there. I couldn’t understand the book very well because I really wasn’t up to it. But there in the last paragraph at the end of the book it said, “Some new ideas are here needed.” And so there I was. Some new ideas were needed? OK! So I started to think of new ideas.

What book does Richard Feynman refer to exactly?


Dirac’s The Principles of Quantum Mechanics (1930) ends with the paragraph:

The present theory is very symmetrical between the electrons and protons. The symmetry is not mathematically perfect, as may easily be verified, when one takes interaction between the electrons into account. This cause, however, hardly appears to be sufficient, according to present ideas, to account for the very considerable observed differences between electrons and protons, in particular their different masses. Possibly the solution of this difficulty will be found in a better understanding of the nature of interaction.

Feynman’s “Some new ideas are here needed” seems like a reasonable paraphrase of the last sentence.

  • It's worth noting that this book is, to quote Wikipedia, a landmark in the history of science. It's still used today as one of the main textbooks on quantum mechanics, and was written by one of the creators of the field. So when Feynman said "Dirac's book", it's already quite likely that this was the one he meant.
    – Rand al'Thor
    Oct 27 '18 at 21:15
  • Feynman read the book when he was a teenager and this might account for his lack of accuracy.
    – q-l-p
    Oct 27 '18 at 21:27
  • @Rand al'Thor: what is still used is the 4th edition, which is significantly changed from the 1st edition (as quantum mechanics has been developed quite a bit further), and very probably doesn't have the same last paragraph.
    – Peter Shor
    Nov 9 '18 at 19:40

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.