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By Gerald Holton
If you heard or read Leo Kadanoff’s Presidential Address to the April APS Meeting (published in APS News, July 2008), you know that this society and its members have a big task now to stem the decline in research funding, in status, in education, and in the general scientific literacy of the public—not only for ourselves but also for our country.
What I have to relate here may, I do believe, give added conviction and authority to those who want to be effective in this difficult task. My first point concerns the sense of self, the intellectual identity, of each of us individually; and my second, related, point will concern our opportunity, perhaps even duty, to our students.
As to the first point: physicists and other scientists tend to be understandably oriented above all to the future of their field rather than to its past. Such are the characteristic identities of pioneers at a frontier, rather than of scholars focusing on the past.
Let me illustrate this view, together with a rare conversion experience. In 1972, the Enrico Fermi summer school of physics was held in Varenna, Italy, on Lake Como. The topic was “The History of 20th-Century Physics.” The faculty for this school consisted of a small group of physicists and historians of science. To our delight, Paul Dirac agreed to participate. We, the faculty, all met before the school started, to synchronize our work. Dirac listened intently, and finally spoke up in his quiet way, saying “I don’t understand why there should be a history of physics. Either a thing happened, or it did not.” This remark produced panic among the rest of us.
Near the end of the summer school’s term, Dirac gave a set of lectures to our students, saying at the start: “I have learned a great deal here at Varenna...I have learned to appreciate the point of view of the historian of science...[By contrast,] the research physicist wants rather to forget the way by which he attained this discovery....He feels perhaps a bit ashamed, disgusted with himself, that he took so long.”
“However, with the understanding of what the historians of science are concerned with,” Dirac continued, “I have tried to think over the past...[and] how these things led me to the style of work which I followed later in life.” And then he gave a splendid set of three historical lectures, “Recollections of an Exciting Era,” which were published later.
To be sure, few scientists have experienced a conversion like Dirac’s.
Only rarely is a researcher interested in reading one of the publications on the history of science, or for that matter in reading a physics paper or volume published many decades in the past—as was done by I. I. Rabi. He wrote that one day he happened to be reading, for sheer pleasure, Maxwell’s Treatise of 1873. That gave him a clue for quickly measuring the magnetic susceptibility of a crystal, a central question in his research project at the time. It was for him not the only time that history helped to transform a present puzzle into a future solution.
For Rabi, and for relatively few physical scientists today, such as Steven Weinberg and Freeman Dyson, a sense of the historical development leading up to their current physics preoccupation has been important for a more comprehensive sense of self. And, I maintain, it should be so for far more scientists. For in truth, for each of us, the science research project of today is the temporary culmination of a very long, hard-fought struggle by a largely invisible community of our ancestors. Each of us may be standing on the shoulders of giants; more often we stand on the unrecognized graves of our predecessors. To know nothing about them is, to me, as limiting in one’s self-regard as not knowing one’s actual parents.
I was lucky to realize this simple fact as a Ph.D. student under P. W. Bridgman. He was not only a hard-driving experimental physicist, who was awarded the Nobel Prize in 1946, but he also eloquently wrote on what was called the operationalist approach to the methodology of science. The first thing a new student of his would do was read his great text, The Physics of High Pressure. And there his first chapter is titled “Historical Introduction”—29 pages on the great sequence of prior high-pressure experimenters, some 75 of them, starting with Hans Christian Oersted in 1823. This is one example of acknowledging the serious debt any advance pays to its genetic forebears.
To illustrate further, let me refer to work I did with two research associates some time ago, published under the title “How a Scientific Discovery is Made.” [American Scientist, Vol. 84, no. 4 (July-August 1997), pp. 364-375] As you know, in 1986 and 1987, there appeared out of the blue several papers on high-temperature superconductivity by the Swiss physicist Alex Müller, formerly a student of Wolfgang Pauli’s, and by Müller’s former student, Johannes Georg Bednorz. Starting in 1983, at the IBM lab in Switzerland, they worked rather secretively, in order that if they failed, they could, as Müller told me, give their work a “burial in very restricted family circumstances, so as not to jeopardize Bednorz’s career.” Yet they caused a great sensation when they announced their findings. They had broken through a long-standing barrier, reaching superconductivity at about 30 K by the completely unconventional use of a ceramic compound with a perovskite structure. Others quickly converged on this new field, and pushed the transition temperature to over 130 K.
I became interested in just how Müller and Bednorz made their discovery. Specifically, what had been the historic treasury of intellectual and material resources that were available to them and were used by them? Happily, both men cooperated with us in giving interviews and exchanging letters. I especially wanted to know how they fitted into the grand, age-old network of available knowledge on the way to the new knowledge. How did their work fit into the big jigsaw puzzle whose pieces were prepared by previous advances?
So we traced, in their own key publications, the explicit and implicit serious citations. Then we looked at the explicit and implicit citations in the publications of those immediate ancestors; and in fact we went further back in this way for a total of about four intellectual generations.
Analyzing the original five papers that comprised the announcement of their breakthrough revealed the number of silent resources that they had put to use: for example, tools for standard observation techniques that are no longer referred to explicitly, such as x-ray diffraction (Max von Laue), or the criteria for identifying superconductivity, namely zero electrical resistance (by Heike Kamerlingh-Onnes in 1911), and the Meissner effect, implicitly referring to a 1933 publication by Walther Meissner and Robert Ochsenfeld. Similarly, the platinum thermometers that Müller’s team used imply references to an 1887 publication by one Hugh L. Callendar of the Cavendish Laboratory, which ushered in the platinum-resistance thermometer as a practical means of measuring temperature.
The origins of the apparatus Müller’s team used to liquefy helium stems of course from the principles of cooling, laid out first by the British physicists William Thomson and James Joule in the 1850s, and by the French chemists Nicolas Clément and Charles-Bernard Desormes in 1819. And so forth. Unwittingly but documentably, the stage for Müller and Bednorz’s discovery in the 1980s had been set by earlier scientists—many long dead, if not forgotten.
And there was one special ancestor of Müller’s work: Johannes Kepler. Müller told me that he had an unusual fascination with perovskites, which have a very high degree of symmetry, and which he had used with great success in many other research projects. This fascination had originally stemmed from his having been a student in Pauli’s class, when Pauli was sharing his ideas on an essay he was writing on Kepler and his archetypes, especially those five Platonic, highly symmetrical bodies. So it turns out that Kepler had helped Müller and Bednorz discover high-temperature superconductivity!
From these and many other examples we can generalize that any significant advance relies, not vaguely but documentably, on a large, international, identifiable set of earlier contributions, all serving the emergence of new science or technological achievement. This fact also supports the old assumption that there is some underlying unity in science and technology, not a unity found by one grand synthesis, but a different unity, an operational one, in which the interlinking parts of science and technology help one another.
The lesson here is that Dirac was correct in his advice in his Varenna lectures. Indeed, every advance reported in an APS meeting or publication is a new fruit on an old family tree, one with many branches, near and far. Moreover, these long-gestated fruits of science have nourished not only current physicists, but were, and continue to be, crucial aid for other sciences, for applications—and for the forces working on behalf of enlightenment, of reason and sanity, and potentially for upgrading the human condition.
In this recognition lies a large part of the moral authority of the scientific profession. And when not enough scientists assert it, others rush in, to define it in their destructive ways, as they have done again and again. I dare to confess frankly that a good part of the reasons for my doing some of the things the award citation asserted about my activities has been largely motivated by the view that our physical sciences, when seen through the twin lenses of the achieved present and the painful development over centuries, are at least as important a part of humanity’s culture and long-term health as any other enterprise.
Of course, at this point I hear some skeptical voices. For many scientists, the adrenaline of the day-to-day excitement in the lab is quite enough to feel utterly secure within themselves. Others make do very well with a combination of good work at the bench or desk, plus important public service, like many of our role models, or those who battle the tone-deaf administrators and the scientific deniers of our time.
Assuming these roles is of course needed, too—and is fulfilling for those who do, and crucial for the rest of us. But there is at least one role that seems to me to require from the scientist a living sensitivity and witness to serving as a link in a grand chain of being. This role is that of educator.
And so I come to my second point: how best to attend to the opportunity, perhaps duty, that we may have to our students.
If you accept the suggestion that many working scientists deserve a larger, more secure sense of identity, being confident beneficiaries of the past and contributors to the present culture and civilization, it follows that they have also an opportunity to help their young colleagues and students at least to glimpse their own role in this great venture. This can be done easily when one is teaching physics, where we convey to students many of the great breakthroughs, from Galileo to Richard Feynman, and today’s favorite topics. What I am about to suggest applies to any of these, but let me concentrate for a moment on the opportunity to teach relativity theory in this mode, as one example.
Students usually look forward to being introduced to this topic, and there are by now hundreds of ways to present the main concepts and equations, and their uses. That must be done. But many instructors have found that there is in addition even more excitement and result, by making a little room to give students a glimpse of why and how this theory came about, and thus became a key part of physical science.
Even in Einstein’s own writings, it is easy to find what he regarded as the immediate antecedents of his theory. I would recommend turning to one of Einstein’s early love letters to his future wife, Mileva Maric. Writing in August 1899, he says he has been reading Heinrich Hertz on Maxwell’s theory, and he presents to Mileva his conclusion: “The introduction of the word ‘Ether’ in the electric theory has led to the conception of a medium of whose motion one can talk, without, I believe, connecting with that assertion a physical sense.”
So, in 1899, six years before his 1905 paper, he already had the audacity to dismiss the ether. Later, Einstein added that the Fizeau experiment of 1851, stellar aberration, and Michael Faraday’s induction experiment were the critical antecedents to his own work. And in his autobiography, written in 1946, he added that his early self-education included reading Gustav Kirchhoff and Hermann Helmholtz, especially on Maxwell’s theory. Indeed, he referred to his own approach to physics as the Maxwellian Program.
Now that we have begun to make the student aware of some of the steps, so to speak, of a ladder up through which relativity came into being in Einstein’s mind, we can stop at this important point to explain what in Einstein’s view is that Maxwellian program. It is of course an exemplification and realization of the oldest motivating force in physics, namely, the attempt at a grand synthesis, at a unification of disparate elements—a tradition I have liked to call the Ionian Enchantment, going far back in time.
In a way, some of the most recent works being presented at this APS meeting are children of that great family dynasty: the movement toward unification within a branch of science, going back to (among others) the Vienna Circle for the Unity of Science, then further back to the syntheses worked on by Maxwell, by Faraday, by Oersted, by Kant and the nature philosophers. This takes us all the way back to Newton, who in his preface to the Principia Mathematica said he hoped that by mechanical principles one could “derive the rest of the phenomena of nature,” and ultimately back to Thales of Miletus in ancient Greece. And then we can go forward to what Einstein initially called the generalized relativity theory, and on to today’s ideas of a theory of the synthesis of all forces. Giving some idea of this grand arc is showing science as a living being, with huge energy, struggles, despair, visions, vexations, and victories.
In short, when students are dealing with the work of any of those who helped our current science to be born, they should see that physics, through the centuries-long application of rationality, intuition, and skill, has achieved a high degree of organic coherence, rather than being just one detail after another, like those separate chapters in so many textbooks. So, should not at least some of us, when teaching, for example, about Einstein’s work as reflected in his equations, let it be known also that Einstein himself noted (in “Motive des Forschens,” 1918) that “the supreme task of a physicist,” as of any intellectual, is to form “a coherent and lucid world picture”?
And, for that matter, should it not be known also that Einstein urged a fierce defense of science, as well as upgrading the conditions of mankind? Would that not add greatly to the sense of self of future scientists, a sense that may be diminished if they see their main purpose only to do yet another narrow set of assigned tasks? And, just possibly, given this larger self-confidence as sons and daughters of an extraordinary family, would that not allow them, in this era of unreason and neglect, to act when necessary, on behalf of our profession—and beyond?
Dear friends and colleagues, having shared a call of conscience in Bram Pais’ spirit, I thank you again for this honor, and for your attention.
—St. Louis, Missouri, 15 April 2008.