Saturday, August 01, 2009

Pure Pauli

In 1921, Einstein reviewed a newly published book surveying his great special and general theories of relativity:
Whoever studies this mature and grandly conceived work might not believe that its author is a twenty-one year old man. One wonders what to admire most, the psychological understanding for the development of ideas, the sureness of mathematical deduction, the profound physical insight, the capacity for lucid, systematical presentation, the knowledge of the literature, the complete treatment of the subject matter, or the sureness of critical appraisal.
The book's author was one Wolfgang Pauli who went on to win the Nobel physics prize in 1945 and is universally acknowledged to be one of the greatest theoretical physicists of all time. Einstein called him his intellectual heir. (Pauli should not be confused with Wolfgang Paul, the 1989 Nobel physics laureate, whom Pauli humourously referred to as his "real part".)

I find Pauli and his approach and style utterly fascinating. There is something very pure about him. It is not for naught that he was known as "the conscience of physics" for much of his career, such was his uncompromising dedication to truth and willingness to face facts honestly. In this respect, he reminds me a lot of Orwell, another thinker of unbending integrity, whatever his philosophical and political faults.

Pauli's Nobel lecture provides a classic illustration of what I'm alluding to. He was awarded the prize for his discovery of the exclusion principle, also known as the Pauli exclusion principle. Now, any normal person called upon to deliver a lecture on the occasion of the award of such a prize of high distinction would focus, however discreetly and "modestly", on praising his own achievements. This, of course, is precisely what most of the Nobel laureates have done. But not Pauli. In his Nobel lecture (entitled "Exclusion principle and quantum mechanics"), Pauli delivers an unflinching, indeed an altogether unflattering, assessment of his own discovery and declares himself singularly dissatisfied. He concluded:
From the point of view of logic, my report on "Exclusion principle and quantum mechanics" has no conclusion. I believe that it will only be possible to write the conclusion if a theory will be established which will determine the value of the fine-structure constant and will thus explain the atomistic structure of electricity, which is such an essential quality of all atomic sources of electric fields actually occurring in Nature.
That's pure Pauli.

This is my favourite picture of Pauli. It's a passport photograph taken some time in 1940 just before Pauli (a Jew) left Hitler's Europe to take up a position at the Institute for Advanced Study in Princeton, New Jersey. I loved that photo from the moment I laid eyes on it. It seemed then, just as it seems now, to capture something of the essential spirit, attitude and approach of Pauli: the intellectual purity and honesty; the penetrating gaze of the theorist (in the highest and best sense of that much misunderstood word); the simplicity; and the integrity. Earlier on today, I discovered that Pauli's wife also thought there was something very special about that image: "To my opinion, this is the best existing photo of W. Pauli," she remarked.

No account of Pauli would be complete without at least one of the many legendary Paulian quotes or anecdotes. I end with Pauli's inimitable and incontrovertible rebuttal to the publish or perish mentality so beloved in the academic community:
The fact that the author thinks slowly is not serious, but the fact that he publishes faster than he thinks is inexcusable.
Again, pure Pauli.

More on Pauli:

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