Notes on Freeman Dyson’s story on his encounter with Fermi

Freeman Dyson

Freeman Dyson was a great physicist that worked at Cornell University and then at the Institute for Advanced Study. At Cornell he worked with Hans Bethe and Richard Feynman, both got the Nobel prize, though perhaps Richard Feynman is the better known to the general public of the three.

The story

In a clip on YouTube, Freeman Dyson tells his story of his encounter with Fermi.

At the time he worked with a team and developed a numerical model that seemed to accurately represent the results of some experiments. He was very enthusiastic about the results and wanted to show that to Fermi, who was the leading expert in that area. So Hans Bethe arranged for him to meet Fermi, in Chicago.

So Freeman Dyson arrives in Chicago, meets Fermi, shows him the results and Fermi tells him bluntly that he’s not impressed, that in physics you either have to have some clear physical model in mind or a rigorous mathematical basis, and Freeman’s approach had neither.

Freeman then asks: how about the numerical agreement? Fermi then quotes John von Neumann that with four parameters you can fit an elephant and with five you can wiggle it’s trunk.

Freeman thanked Fermi, and the whole meeting was finished in 10-15 minutes.

He then continues to say how profoundly useful was that meeting, how impressed was by Fermi’s intuition that the approach was not good, that Fermi was right. He also tells how it was a difficult time, to give the bad news to the team he worked with, but that it the end it was for the good.

The moral

On one side there is the obvious morale of the story that Freeman Dyson points to. Of particular interest for software, consider the large number of parameters involved in machine learning algorithms.

In addition to that, for me part of the moral is that Freeman Dyson himself did really well in the encounter. For him a quick conversation was enough to get an important idea. He got a straight message, he listened to it, figured out what it means and acted on it ratioanaly, despite emotional difficulties.

References

Freeman Dyson - Fermi’s rejection of our work - 6 Sep 2016