The Fermi Alternative

Given the recent Feynman explosion (timeline of events), some people may be casting about looking for an alternative source of colorful-character anecdotes in physics. Fortunately, the search doesn’t need to go all that far– if you flip back a couple of pages in the imaginary alphabetical listing of physicists, you’ll find a guy who fits the bill very well: Enrico Fermi.

Fermi’s contributions to physics are arguably as significant as Feynman’s. He was the first to work out the statistical mechanics of particles obeying the Pauli exclusion principle, now called “fermions” in his honor (Paul Dirac did the same thing independently a short time later, so the mathematical function is the “Fermi-Dirac distrbution“). He was also the first to develop a theory for the weak nuclear interaction, placing Wolfgang Pauli’s desperate suggestion of the existence of the neutrino on a sound theoretical footing. Fermi’s theory was remarkably successful, and anticipated or readily incorporated the next thirty-ish years of discoveries.

More than that, he was a successful experimental physicist. He did pioneering experiments with neutrons, including demonstrating the fission of heavy elements (though he initially misinterpreted this as the creation of transuranic elements) and was the first to successfully construct a nuclear reactor, as part of the Manhattan Project. The US’s great particle physics lab is named Fermilab in his honor.

One of the difficult things about replacing Feynman is that a lot of the genuinely admirable things about his approach to physics are sort of bound up with his personality. Meaning that it’s easy to slide from approach-to-physics stuff– spinning plates at Cornell, etc.– to relatively wholesome anecdotes– dazzling off-the-cuff calculations, cracking safes at Los Alamos– into the strip clubs and other things that make Feynman a polarizing figure.

Fermi brings a lot of the same positive features without the baggage. He had a similarly playful approach to a lot of physics-related things– the whole notion of “Fermi problems” and back-of-the-envelope calculations is pretty much essential to the physics mindset. Wikipedia has a great secondhand quote:

I can calculate anything in physics within a factor 2 on a few sheets: to get the numerical factor in front of the formula right may well take a physicist a year to calculate, but I am not interested in that.

He was also a charming and witty guy, with a quirky sense of humor (the photo above has a mistake in one of the equations, and people have spent years debating whether that was deliberate, because it’s the kind of thing he might’ve done as a joke on the PR people). He even has his own great Manhattan Project anecdotes– he famously estimated the strength of the blast by dropping pieces of paper and pacing off how far they blew when the shock wave hit, and prior to the Trinity test was reprimanded by Oppenheimer for running a betting pool on whether the test would ignite the atmosphere and obliterate life on Earth.

He also has the wide-ranging interests going for him. His name pops up all over physics, from statistical mechanics to the astrophysics of cosmic rays. And just like Feynman is more likely to be cited in popular writing for inspiring either nanotechnology or quantum computing than for his work on QED, Fermi’s true source of popular immortality is that damn “paradox” about aliens.

While the personal anecdotes may not quite stack up to those about Feynman, there isn’t the same dark edge. Fermi was happily married, and in fact moved to the US because of his wife, who was Jewish and subject to the racist policies put in place by Mussolini (they left directly from the Nobel Prize ceremony in 1938, where Fermi picked up a prize for work done in Rome). I’m not aware of any salacious Fermi stories, so he’s much safer in that regard.

Given all that, why is Fermi so much less well-known than Feynman? Partly because a lot of his contributions to physics were excessively practical– experimentalists tend to be less mythologized than theorists, and his greatest theoretical contributions came through cleaning up ideas proposed by Pauli. Mostly, though, it’s because he was a generation older than Feynman and died younger, in 1954. He never got the chance to be a grand old man, and didn’t live into the era where the sort of colorful anecdotage that so inflates Feynman’s status became popular. Had he lived another twenty years, things might’ve been different.

(It’s also interesting to speculate about what Schrödinger’s reputation would be had he been closer to Feynman’s age than Einstein’s. Schrödinger would’ve loved the Sixties, between his fascination with Vedic philosophy and the whole “free love” thing. But had he been alive through then, the skeevy aspects of his personal life would probably be better known, because most of his more sordid activities took place in an era when people didn’t really talk about that sort of thing in public, let alone write best-selling autobiographies about it.)

Anyway, that’s my plug for Fermi. If you find Feynman too problematic to promote– and that’s an entirely reasonable decision– Fermi gets you a lot of the same good stuff (great physicist, playful approach to science, charming and personable guy), without the darker side. He should get more press.


(That said, Fermi is one of the figures I regret not being able to feature more prominently in the forthcoming book. The problem is, the focus of the book is on process, and Fermi’s one of those guys whose process of discovery consisted mostly of “be super smart, and work really hard.” I couldn’t come up with a way to fit him into the framework of the book, other than the notion of back-of-the-envelope estimation. But you can’t do that without bringing math into it, and that would’ve pushed the book into a different category…)

11 thoughts on “The Fermi Alternative

  1. Good post. I would say that Fermi’s contributions easily exceed that of Feynman; there is not an area of modern physics that he did not touch. Except perhaps for general relativity his fingerprints are all over the place. At Los Alamos there was an entire (one-man) division created for him; the purpose was to give him problems that had stumped others.

    Fermi was the last universalist who truly excelled in both theory and experiment and who also had a complete grasp of physics, and I think that if he had lived longer he might have become almost as famous as Einstein, at least on a scientific basis. I think it’s a little unfair to say that his “greatest theoretical contributions came through cleaning up ideas proposed by Pauli”; the beta decay theory was a wholly original and comprehensive contribution and has stood pretty much unchanged since then. It’s hard to imagine that the same man would both create this theory and design the world’s first nuclear reactor. Those two achievements alone would put him in a unique class of his own.

    Fermi was also far more modest than Feynman about self-promotion and disdained publicity so I am not surprised that he was never as publicly known. In personal interactions he was always friendly but also always kept a certain reserve. But he shared at least one quality with Feynman; he never cared for class and could speak to both other Nobel Laureates and to the janitor at Chicago on equal terms. And no work was too menial for him.

    For me, the biggest scientific compliment to Fermi comes from C. P. Snow who said “If Fermi had been born a generation earlier it would not be too much to imagine him first discovering Rutherford’s atomic nucleus and then developing Bohr’s theory of the atom. If this sounds like hyperbole, anything about Fermi is likely to sound like hyperbole.”

    The best material on Fermi can be found in the wonderful biography by his wife Laura (“Atoms in the Family”) and the perceptive biography by his friend and protege Emilio Segre (“Enrico Fermi: Physicist”).

  2. (Belatedly realizing that the post title sounds like a Big Bang Theory episode…)

    I agree that it’s unfair, but then again, it’s hard to find a description of Fermi’s beta decay theory that doesn’t start with a mention of Pauli’s proposal for the neutrino. So I think there is definitely a perception that it’s not really on the same level of genius as Feynman. For me, the fact that he did both theory and experiment is a significant boost, though.

    I like the C.P. Snow quote, too, and almost put it in the post, but decided it was too long.

    Now I have to resist the temptation to go check out a bunch of Fermi biographies from the college library… Page proofs first, dammit.

  3. You’re feeling very sleepy.

    Atoms in the Family. Atoms in the Family. Atoms in the Family.

  4. This set me to wondering if the lack of emphasis on great experimental advances and great experimental physicists (Rutherford also had excellent insight into what experiments needed to be done) is due to the self-created cult of Feynman as an attempt to hook onto the coat tails of the media-created cult of Einstein. It didn’t help that Fermi didn’t seek publicity on his own or live into retirement years when he might have given public talks, or even show up on TV in the 60s and 70s to comment on electroweak discoveries or even Three Mile Island.

  5. Actually, Fermi made important contributions in general relativity as well. For instance, he introduced the notion of Fermi coordinates in curved spacetime.

  6. Fermi’s death from cancer at the depressingly young age of 53 is also a likely contributor to his comparative lack of broader appreciation. The guy was amazing, and he didn’t have an extra twenty years to do popularization (and self-promotion) like Feynman.

  7. I enjoyed this post immensely. Yes, we need more written about the others who contributed so much and Fermi is certainly a great candidate. But I would like to name another who was mentioned in passing above. I would like to nominate Pauli as another choice. All his tremendous and still valid professional work. His “Dear Radioactive Ladies and Gentleman” letter written because he would rather go dancing than attend the conference. His obsession with 137…the hospital room…that alone gets an interesting article out of a writer. Other antidotes abound…the Pauli Effect. AND his association with C G Jung! Why only one biography in all these years? Is he not fascinating enough for science writers? I also want to ask why is that book $50 in paperback? Doesn’t Oxford University Press want people to read it?
    OK. I’ve calmed down now. Since I haven’t scrapped together the coin for the book and since I haven’t found it online I want to ask this: Why was he not involved in any, none, of the war work that occupied physicists during WW II? I have found nothing to explain that. Was he more of a pacifist than Einstein? Einstein was happy to offer suggestions about gaseous diffusion when asked. So why did Pauli not become involved?

  8. Why was he not involved in any, none, of the war work that occupied physicists during WW II?

    Fermi was involved in the Manhattan Project, but remained in Chicago. He was in charge of the first controlled fission reaction, which was done under the old stadium on the University of Chicago campus. The successful result of that experiment was reported in one of the most famous telephone calls in history:

    “The Italian navigator has landed in the New World.”
    “Are the natives friendly?”
    “Yes, very friendly.”

    I’m not sure whether Fermi chose to remain in Chicago, or whether his Italian origin meant that he was intentionally excluded from Los Alamos (Italy being one of the Axis powers).

  9. Fermi did the reactor work in Chicago, but was eventually talked into going to Los Alamos. He was there for the Trinity test, and famously estimated the magnitude by dropping pieces of paper and measuring how far they blew.

    Pauli was never at Los Alamos, or involved in any of the other stuff, I don’t think. I’m not sure if this was a matter of principle, a matter of suspicion about his background, or just the fact that he was a theorist’s theorist. His effect on experiments was so strong and negative that one experimental disaster was jokingly attributed to the fact that Pauli had been in the city in question at the time when things went pear-shaped, changing trains on his way to visit someone else. That’s not the sort of guy you want involved in a massive engineering project making things that go BOOM…

  10. I’m not surprised that Pauli was not involved in the Manhattan Project, because he was not a collaborator. He wrote few papers with coauthors, and this was not the style of work needed for the Manhattan project unless someone had very specific expertise in nuclear physics or other important areas like statistical physics and hydrodynamics.

    I think his nationality was least important (consider Klaus Fuchs) along with the risk that all of the experiments would stop working, but people may have had questions about his mental stability.

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