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Reflections on the APS and the Evolution of Physics

By John J. Hopfield

John H. Hopfield

As a graduate student I once got into an argument with a chemist about the nature of physicists. I had always thought of physicists as very broad scientists. In my (then young) experience, most physics professors I had known were capable of teaching any undergraduate course in physics. Undergraduate students were in turn responsible for the entire available undergraduate course offering in physics. In chemistry, by contrast, undergraduates specialized, and your typical physical chemistry professor could not possibly be assigned to teach, say, organic chemistry, even at the introductory level. 

I attributed this difference to the breadth of physicists. My chemist friend utterly disagreed. The difference, he maintained, was that physics was a young and a narrow science, a science so narrow that the intellect of one person could span it. Chemistry had developed more fully, was a more mature science, and was now so rich and broad that it could no longer be meaningfully spanned by a single individual.

As a field of knowledge expands, and its number of practitioners increases, a point of instability is reached at which the enterprise splits into multiple components. The split may be complete, or leave some connective bridge, but either way the knowledge and the scientists become isolated to sub-compartments to better pursue the subject.

I have watched this going on since the first APS meeting I attended in January 1958, in New York. There were talks from all corners of physics. And prior to 1953, the APS apparently felt no use was to be served by singling out one researcher or accomplishment with a prize. There were invited talks given by the luminaries of the various corners of physics, but no prizes.

As physics began to be larger than the span of single individuals, and as the number of physicists working in an area became so large that no one personally knew all the major contributors even to his/her own field, let alone to physics as a whole, this was no longer the case. My theory of scholarly prizes and awards is that they serve a social function within a science, by pointing to role models and particularly valuable contributions within a group that has become so large and fractionated that it is no longer completely obvious to any one individual who the major players are, and why. This function does not exist when the enterprise is small and unfractionated. The first APS Prize, the Oliver E. Buckley Prize in Solid State Physics, was created in 1953.

Physics is now far larger–the number of papers at the March Meeting has grown by a factor of 10–and there are now over 30 prizes and awards. The symptom that the field is maturing and fragmenting is seen in the rather specific nature of the prizes and awards, which are carefully allocated to subfields of physics. It is a posture now very similar to that of chemistry and the American Chemical Society.

The subspecialization has become so strong that instead of going to hear a set of diverse people talking about truly prizeworthy science, physics proles prefer to attend sessions devoted to their subspecialty. Physics is becoming more mature, becoming fragmented, becoming larger, with a more complex sociology that comes spontaneously with increased size. Prizes and awards are now an established and significant part of our culture. At a larger scale, the same fragmentation is seen in the creation of new divisions, fora, and topical groups of the APS.

If maturing means fragmentation and specialization, what (nontrivial) problems does this create for the APS and for physics? I tend to look at such issues by going back to first principles, asking what is the organization for. I take its major purpose as the facilitation and encouragement of physics research, with emphasis on the US scene. As such, it runs meetings, publishes journals, lobbies government, presents a variety of advice and services to its members. How will this maturation and fragmentation affect the APS?

Publishing. When I first joined the APS in 1956, I did so in order to subscribe to the Physical Review. Nowadays very few of our members subscribe. The maturation in publishing began with the realization that as physics fragmented, there was more scope for specialty journals to compete with our major flagship. So the Physical Review was split into multiple parts. That someone could subscribe to only a sub-part, was a direct reaction to specialization. 

The digital world has enhanced this ability to specialize in what we are exposed to. In this day of electronics, hardly anyone has a volume of Phys Rev X in hand. Articles are read on the screen, or printed out, one at a time. The nominal paper publication with articles grouped together is no longer really relevant to the reader. It is thus no longer necessary to proliferate more and more specialty journals to compete. What is important is a refereeing system that can succeed in obtaining highly authoritative and useful referee reports for papers from any corner of physics. For this we rely on the fact that the excellent refereeing culture of physics has continued in spite of the maturation of the field, and we rely on the superb organization of the APS editorial office. 

The same electronic technology that solves this problem of specialization creates Web competition such as arXiv.  How and from whom we will get our scientific literature information 10 to 20 years from now is a rather open question for all fields of science, maturing or not. 

Lobbying and the Government Support of Physical Science. Federal support of physics, at the time of my first APS meeting in 1958, was dominantly motivated by the past success of physics discoveries in the military sphere. The NSF was new and relatively small. GE, Westinghouse, ATT, Union Carbide, Ford, GM, and RCA had credible long-term research laboratories. They felt that a long-term investment was necessary to be able to find and develop ideas from physics into their future products. The highest corners of the executive branch were very concerned about physics and the national defense. There was no real problem in 1958 about getting good physics policy advice understood by the government, or in getting good physicists to give it. 

In 2006, the NRC report, Rising Above the Gathering Storm, chaired by Norm Augustine, had as its major conclusion that the failure of the US to adequately support the physical sciences over the past 20 years is going to have a major negative effect on the economic situation of the US.  This failure results from both the decreasing of the funding per university scientist available from the federal government and the near collapse of long-term industrial research in the physical sciences. The US economy rests very heavily on leadership in civilian technological innovation, and the report documents that this leadership is imperiled by the current support climate. 

In 1958, the APS really did not need to lobby Congress or the administration. In contrast, the APS is now an organization that devotes a considerable effort to lobbying Congress and the executive branch. It took a huge lobbying effort to get the competitiveness initiative to even obtain a high level hearing in the executive branch, and more effort yet to get it included in the 2006 state of the union address. The APS can be proud of its contribution to getting the program put forward by the Augustine committee into legislation.

The recent basis for arguing for funding for physical science was in support of the US as an economic power, through the technological innovation that depends on advances in physical science. But our effort must go beyond those parts of physical science that are obviously and directly tied to economic impact. Our advocacy of support must also be for those areas and aspects that are less directly tied, those parts of physical science that are iffy and longer-term, and for the entire intellectual enterprise as being an inseparable whole.

Why should physics be supported by the average US citizen to the tune of many billion dollars a year? Why should it have more support than philosophy, art, music, or literature? It is the historical record of the contribution of advances in physics to human well-being, to the economy of the world, and to defense that explain this difference, and justify believing that this should continue to be the case.

If we are to continue to be funded at such a level, we owe it to the world that a significant fraction, the larger part, of our requests for federal funding be plausibly relatable to human well-being on the timescale of one to five decades. It is increasingly obvious that this well-being is conditioned on bringing the atmospheric greenhouse problem under control. Unfortunately, it has been relatively easy to do interesting physics involved with weaponry. It has been less easy, less sexy, to try to find good physics in areas such as energy conservation. In my more pessimistic moments, I recall the closing refrain of T. S. Eliot’s “The Hollow Men:”

This is the way the world ends
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.

The United States has legitimate worries about nuclear proliferation, nuclear deterrence, and terrorist attack. But I believe physics has been worrying too much about “bang” when “whimper” is steadily, stealthily approaching. The world would be better served if physics became more oriented toward issues in electricity generation, storage, conservation, CO2 and related problems.

 While the chief reason for strong physical science funding in the 1950’s may have been the potential weapons of military competition rather than the weapons of innovations and economic competition, there is a very important common feature to the way that we have asked for governmental support in the two eras. The rising tide must float all boats, and while the maturing of physics has somewhat loosened the ties between the boats, all boats are still somewhat rafted together. The preservation of physics as a single entity depends on these ties between sub-disciplines.

Meetings. The maturing of physics into sub-disciplines and the immense advances in communications technology have appreciably changed the structure and content of our meetings. In the late 1950s, the dominating purpose was to be able publish and communicate a new result. ArXiv or other equivalents now allow me to do this without going to a meeting, so general meetings no longer serve as a significant publication tool.

The number of more specialized divisional and special topics meetings has increased—physicists do still want to get together; we are not entirely antisocial animals. Some of the slack of the demise of national general APS meetings has been taken up by successful section meetings. However, the evolution of meetings, and the demise of significant general meetings, is a symptom of the maturing and fractionating of our science and indeed is a contributor to its fractionization.

A task force on the future of the April Meeting, chaired by Chris Quigg, reported to the APS Council in 2006. I had been afraid that their report might have led to the demise of this meeting. Instead, it reported on a meeting that was still vibrant and somewhat diverse, and described several mechanisms and experiments designed to keep it so. I look forward to the implementation of these ideas.
What is physics? To me–growing up with a father and mother both of whom were physicists–physics was not subject matter. The atom, the troposphere, the nucleus, a piece of glass, the washing machine, my bicycle, the phonograph, a magnet–these were all incidentally the subject matter. The central idea was that the world is understandable, that you should be able to take anything apart, understand the relationships between its constituents, do experiments, and on that basis be able to develop a quantitative understanding of its behavior. Physics was a point of view that the world around us is, with effort, ingenuity, and adequate resources, understandable in a predictive and reasonably quantitative fashion. Being a physicist is a dedication to a quest for this kind of understanding.

When my interests in such a science turned from crystalline solids to biological matter in 1970, most physicists took that as leaving physics. To me it was merely changing from the physics of crystalline matter to the physics of biological matter. Some 30 years later I was elected APS vice president. That is a testimonial to the idea that physics is a point of view about the world, that diverse kinds of subject matter will come and go, but that it is the quest for a physicist’s kind of understanding about the world that unites us as physicists, and will continue to do so.

Physics has many times had to make a choice between striving to keep a new component, a teenage child as it were, within the fold, or to send it out into the wilderness as a separate discipline. I am gratified that many–perhaps most–physicists now view the physics of complex systems in general, and biological physics in particular, as members of the family.

John Hopfield is the Howard A. Prior Professor of Molecular Biology at Princeton University. He served as APS President in 2006.

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