Tuesday, 10 May 2016

Did Bergson Influence Einstein’s Nobel Prize?

 In a recent book, The Physicist & the Philosopher (Princeton University Press, 2015), and in a Nautilus post a few weeks ago, historian Jimena Canales claims that the philosopher Henri Bergson’s criticisms of relativity theory influenced the Nobel Prize committee in its deliberations regarding a prize for Einstein, and helped ensure that there would be no Nobel Prize for relativity.

Interesting, if true.  Moreover, if true, this is something that has evaded Einstein’s biographers, and so would be a major contribution to Einstein scholarship.  But I’m not convinced.

Why not? Canales’ claim is based, not on new documentary evidence previously unavailable to historians, but on a novel and idiosyncratic reinterpretation of something that has long been in the public record, the presentation speech by Svante Arrhenius, Chair of the Nobel Prize Committee.  I don’t think that the text of the speech bears out Canales’ interpretation.  Moreover, Canales’ claim is at odds with the conclusion drawn by Abraham Pais, who was permitted to examine the documents considered by the Nobel Prize committee and devoted a section of his biography of Einstein to what he found.  I will quote Pais’ conclusion below.

Background: in 1905, his “annus mirabilis,” Einstein published a number of seminal papers.  This included the classic papers on special relativity, one on Brownian motion, and one in which he introduced the hypothesis of light quanta.  From this hypothesis Einstein derived a prediction about the photoelectric effect: that there would be a linear relation between the energy of electrons released by light impinging on a metal and the frequency of the light.  This relation was confirmed in 1916 by the careful experiments of Robert Millikan.  In 1915 Einstein added the general theory of relativity to his list of accomplishments, and it was Eddington's eclipse observations of 1919, verifying a prediction of general relativity, that brought him widespread fame outside the physics community.  By 1921 it was clear that he deserved a Nobel prize, and there was an embarrassment of riches as to what to base the award on.

Honestly, I would have regarded it as a tough call. The 1905 paper on special relativity is terrific, but it's largely a (much-needed) clarification of the foundations of electrodynamics, and much of its content is foreshadowed in the work of others, notably Lorentz and PoincarĂ©. I've recently had occasion to read through much of Einstein's work on the light quantum hypothesis (in conjunction with supervising a dissertation by Molly Kao), and I've come to appreciate how instrumental Einstein was in the development of the quantum theory.  General relativity is certainly worth a Nobel Prize, but nonetheless, I’m not sure that the Nobel Prize committee’s decision to single out the light quantum work was not the right decision.

At any rate, in 1922 Einstein was awarded the Nobel Prize for 1921 (deferred one year).  The citation said that the Prize was “for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect.”  Here's what Arrhenius says in the opening of his presentation speech.

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

There is probably no physicist living today whose name has become so widely known as that of Albert Einstein. Most discussion centres on his theory of relativity. This pertains essentially to epistemology and has therefore been the subject of lively debate in philosophical circles. It will be no secret that the famous philosopher Bergson in Paris has challenged this theory, while other philosophers have acclaimed it wholeheartedly. The theory in question also has astrophysical implications which are being rigorously examined at the present time.

Throughout the first decade of this century the so-called Brownian movement stimulated the keenest interest. In 1905 Einstein founded a kinetic theory to account for this movement by means of which he derived the chief properties of suspensions, i.e. liquids with solid particles suspended in them. This theory, based on classical mechanics, helps to explain the behaviour of what are known as colloidal solutions, a behaviour which has been studied by Svedberg, Perrin, Zsigmondy and countless other scientists within the context of what has grown into a large branch of science, colloid chemistry.

A third group of studies, for which in particular Einstein has received the Nobel Prize, falls within the domain of the quantum theory founded by Planck in 1900. This theory asserts that radiant energy consists of individual particles, termed “quanta”, approximately in the same way as matter is made up of particles, i.e. atoms. This remarkable theory, for which Planck received the Nobel Prize for Physics in 1918, suffered from a variety of drawbacks and about the middle of the first decade of this century it reached a kind of impasse. Then Einstein came forward with his work on specific heat and the photoelectric effect ...

Compare this with Canales’ account of the presentation speech (quoting from the Nautilus post, which reproduces, close to word-for-word, the opening pages of the book):

The chairman for the Nobel Committee for Physics explained that although “most discussion centers on his theory of relativity,” it did not merit the prize. Why not? The reasons were surely varied and complex, but the culprit mentioned that evening was clear: “It will be no secret that the famous philosopher Bergson in Paris has challenged this theory.” Bergson had shown that relativity “pertains to epistemology” rather than to physics—and so it “has therefore been the subject of lively debate in philosophical circles.”

One thing leaps out: Canales attributes a role to Bergson that  Arrhenius does not. Arrhenius does not say that Bergson had shown that relativity pertains to epistemology; he says that relativity “pertains especially to epistemology” and for this reason has been a topic of discussions, pro and con, by philosophers, and he says this before mentioning Bergson. He then says that the theory has been challenged by one philosopher, Bergson, and acclaimed wholeheartedly by others.

Crucially, he does not say that Bergson’s criticisms played any role in the Prize Committee’s deliberations. Canales says that it would have been clear to the audience that Bergson was being mentioned as an explanation for why it was the photoelectric effect, rather than relativity, that was singled out for specific recognition among Einstein’s contributions to theoretical physics, but this is her interpretation, and she offers no evidence that anyone in the audience took it that way.   Canales’ claim that Bergson’s criticisms influenced the Committee’s decision is based solely on this reading of what Arrhenius said that day; this seems to me a very thin thread on which to hang such a claim.

Some light on what did influence the decision is shed in the section entitled “How Einstein got the Nobel Prize” of Pais’ biography, ‘Subtle is the Lord...’. Pais was given access to Committee Reports and letters of proposal concerning Einstein's Nobel Prize, and he reports on these documents in that section.  Pais does not report any mention of  Bergson’s critiques during the Committee’s deliberations. What do seem to have played a crucial role are reports prepared in 1921 and 1922 by Committee member Allvar Gullstrand on the status of the theory of relativity, written at the request of the Committee.  These reports, says Pais, are “highly critical of relativity.”  (Canales omits mention of these reports, though, in the book, she cites this section of Pais’ book, and quotes from his conclusion.)

Pais sums up his conclusions about why Einstein was not awarded the Nobel Prize for relativity in the final paragraphs of that section, which I quote in full.

Why did Einstein not get the Nobel prize for relativity? Largely, I believe, because the Academy was under so much pressure to award him.  The many letters sent in his behalf were never the result of any campaign. Leading physicists had recognized him for what he was. It is understandable that the Academy was in no hurry to award relativity before experimental issues were clarified, first in special relativity, later in general relativity.  It was the Academy’s bad fortune not to have anyone among its members who could competently evaluate the content of relativity theory in early years.  Oseen’s proposal to give the award for the photoeffect must have come as a relief  of conflicting pressures.

Was the photoeffect worth a Nobel prize? Without a doubt. Einstein’s paper on that subject was the first application of quantum theory to systems other than pure radiation. That paper showed true genius. The order of awards for quantum physics was perfect: first Planck, then Einstein, then Bohr. It is a touching twist of history that the Committee, conservative by inclination, would honor Einstein for the most revolutionary contribution he ever made to physics.