Biographical Memoirs Volume 68 (1995) / Chapter Skim
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Walter M. Elsasser
Walter M. Elsasser
Pages 103-166
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From page 103... ...
macle several important contributions to funciamental problems of atomic physics, inclucling interpretation of the experiments on electron scattering by Davisson en cl Germer as an effect of cle Broglie's electron waves and recognition of the shell structure of atomic nuclei. Circumstances later turned his interests to geophysics, where he had important insights about the radiative transfer of heat in the atmosphere and fatherec} the generally accepted clynamo theory of the earth's magnetism.
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From page 104... ...
His father, then in his forties, was callecl into the German army and because he was a lawyer was given a desk job at the headquarters of the Swiss borcler guard. Since he had earlier clevelopecI a severe ulcer, which was exacerbated by barracks foocl, he obtained permission to have his family join him.
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From page 105... ...
In any case, Germans preclominantly thought of science as a philosophical enterprise, and Walter maintained a strong interest in the philosophical aspects of science throughout his career. THE ROAD TO SCIENCE Walter's first encounter with natural science came from a journal of popular science to which his father subscribed.
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From page 106... ...
Stimulated by such quasi-philosophy Walter started thinking about philosophy, in particular Hegel's dictum that, when quantitative differences in some field become pronounced, they tend to turn into differences in quality. This contrasts with the view of the great philosophers of science, that the scientist in his methods has no place for qualities: they pertain to philosophy proper, usually expressed as metaphysics.
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From page 107... ...
He therefore returned to science with a renewed determination to become a physicist. He entered the University of Heiclelberg, where the professor of physics was Phillip Lenarc3, who hacl received the Nobel Prize several years earlier.
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From page 108... ...
an unexpected glimpse into a different orcler of nature in the minute dimensions of the atom that wouIcl soon be expressed in the mathematical language of quantum mechanics. In Munich Walter overIappecl for one semester with Werner Heisenberg, who then obtained his Ph.D.
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From page 109... ...
THE WORLD OF GOTTINGEN Walter cleveloped a close relationship with James Franck, whom he admired greatly. Franck kept his office open, and Walter often founc!
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From page 110... ...
There were many interesting lectures in physics, especially theoretical physics. One course was a seminar titled "The Structure of Matter," which playecl a germinal role in the (levelopment of quantum mechanics.
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From page 111... ...
Einstein then noted a thesis of Louis cle Broglie, which Walter found in the university library. The thesis contained de Broglie's basic iclea that all primary components of matter have wave properties ant!
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From page 112... ...
In this article Born introduced the notion of probability for the first time in quantum mechanics; he proposed that the wave function was a statistical guide for the particles in the sense that the amplitude of the wave specifies a probability for the particle to travel in certain ways. At the end of the paper Born quoted Walter's note saying he hacI correctly interpreted the experimental results of Davisson and Kunsman.
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From page 113... ...
Born, who was a mathematical virtuoso, told Walter that he was not outstanding in mathematics but strong in conceptual thought, where Born felt less secure. A common iclea is that conceptual thought precedes precise mathematical analysis: models ant!
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From page 114... ...
It is the general mathematical theory of machines that operate in a causal manner. By the time Walter had react Wiener's book, quantum mechanics tract lee!
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From page 115... ...
He Earned a useful lesson from van Neumann's celebrated 1932 book The Mathematical Foundations of Quantum Mechanics, namely that any moclel of organic life based only on the existence of statistical features of physics was likely to be false. Walter studied the book carefully, and it taught him that the introcluction of probabilities into physics, which is the most distinctive feature of quantum mechanics, clic!
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From page 116... ...
him since he dice not know Ehrenfest and concluded that it must have been Oppenheimer., Shortly before leaving for Leiden, Walter received a long letter from Ehrenfest concerned not with physics but with the latter's psychological problems. Walter worried about this strange behavior of explaining the complexities of his soul to a stranger half his age, soon to be his assistant.
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From page 117... ...
He then realized that there were two forms of creation, the first being the creation of raw inorganic matter in the "big bang" or other cosmic crevice. But anyone who admits that living things are not just automata has to assume that there is an ongoing creative process in organic life that is much closer at hand ant!
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From page 118... ...
Walter attended PauTi's lectures on quantum mechanics, which he found both powerful and elegant. Although he tried to work closely with Pauli, Pauli clid not seem very interested.
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From page 119... ...
von Laue was very favorably disposed toward Walter, partly because of Walter's paper Interpreting tne experiments of Davisson and Kunsman as demonstrating the diffraction of cle Broglie waves. It was a sign of Walter's psychological difficulties in that period that he could not utilize van Laue's good offices to start over again in theoretical physics, where he had macle a small but spectacular start.
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From page 120... ...
and leaving Germany, Walter spent about half his time in Berlin. It hacl become a cultural capital for many groups from eastern and southwestern Europe, and many talented!
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From page 121... ...
He became well acquainted with Wigner, who introduced group theory as the mathematical tool of choice for atomic physics and later, along with his student Frederick Seitz, provided the quantum mechanical basis for solid-state physics. On one occasion when Walter was "somewhat too easy with my imagination," Wigner counseled him, "One should tackle a problem only when its solution seems trivially easy, it will then turn out to be just at the limits of the manageable; when it appears more difficult, trying to solve it is usually a hopeless undertaking." Walter also came to know Erwin Schrodinger rather well.
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From page 122... ...
The body belongs to matter and is basically a machine obeying causal laws. Walter thought that it was necessary to replace this paractigm with a better one before any creeper understancling of organisms was likely to occur.
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From page 123... ...
Their leacler clemandec] Walter's university identification card, which he then pocketed and told Walter to go home ant!
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From page 124... ...
AS a result of his analytic experience, Walter couIc3 no more question the reality of the unconscious than that of the electrons or atomic nuclei of his professional work. But the reality of psychic phenomena was of a different kind, characterizes]
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From page 125... ...
They met frequently, and Walter was impressed with Kahn's claim that biology was first and foremost the realm of utter complexity. The idea appeared to him because it was simple, abstract, and general and therefore exactly like the notions constructed and used by theoretical physicists.
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From page 126... ...
This had made no sense to him as long as he believed along extravagantly rationalistic terms that all thinking could ultimately be expressed in mathematical form. But if the utter complexity of organisms at both the structural and logical levels impeded the application of mathematical analysis, then conceptual thought could and indeed had to have a respected role in the hierarchy of human mental endeavors.
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From page 127... ...
in France at that time. Walter got to know some of the remarkable men who clirectect French physical science and its instruction.
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From page 128... ...
dynamics of atomic nuclei. The transition from his previous research to the application of quantum mechanics to the nucleus was not difficult.
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From page 129... ...
At that time Niels Bohr and his colleagues in Copenhagen had proposed the liquid drop model of the nucleus in which there was proposed to be a homogeneous agglomeration of protons and neutrons without further internal structure to the nucleus. Though there was considerable empirical support for this model, Walter had certain doubts that led him to think the nucleus would have a degree of internal structure.
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From page 130... ...
student of Born's just after Walter left Gottingen. Both the latter workers received the Nobel Prize in 1963, which they shared with Eugene Wigner in a Tong-clelayecl recognition of his many contributions to atomic and nuclear physics.
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From page 131... ...
He of course had no idea of this possibility when he was cleveloping his ideas about nuclear forces since atomic fission was not cliscovered until 193S, several years after he had left research in nuclear physics. In adclition to his work in Paris on nuclear binding, he and Frank Perrin publisher!
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From page 132... ...
In 1940 they came to America, where they later lived with his sister in Chicago. Walter applied for an immigration visa to the United States ant!
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From page 133... ...
it was the spirit that counted comparable conditions for entry existent in South America but little that correspondecl to the reception of the clowntrodclen masses at the feet of the Statue of Liberty. Two days after disembarkation Walter met I
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From page 134... ...
During his month-Ion" stay in Ann Arbor, Walter frequently visited with a young theoretical physicist, Davic! Inglis, whom he had first known in Pauli's institute in Zurich.
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From page 135... ...
in a long, friendly conversation with Oppenheimer's father in New York, Walter found the man to be warm and generous. After a few days exploring the "marvelous and complex city" of New York, Walter moved on to Chicago, where he visited Margaret and they announced their engagement to her family.
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From page 136... ...
If you want a place in nuclear physics or in astrophysics ~ can Ho ~hsol~elv nothing for vain 1 J ~~ All $~5 ^~$ 7~.... If you are serious about geophysics I can promise you that I will find some salary for you.'' Walter considered Millikan one of the most extraordinary men he had ever met.
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From page 137... ...
they got married. Walter decided to make his break with nuclear physics gradually, so he macle the acquaintance of Charles taur~tsen and his capable group of research students who represented nuclear physics at CalTech.
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From page 138... ...
The American Meteorological Society had for years been urging the American Physical Society to do research on infrared racliation in view of its importance for the atmosphere, but nothing was clone. The far infrared spectra of the atmosphere have a very complicatecT structure that required an understancling of quantum mechanics for its full eTuciciation.
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From page 139... ...
and the relation between quantum mechanics and organic life on the background sketched out above under "Conversion of a Rationalist." After he had clone the atmospheric research for a few years with emphasis on calculations and cirafting, Walter felt frustrated at his previous inability to do experiments. To correct this deficiency, he befrienclecT John Strong, a very successful experimentaTist.
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From page 140... ...
Walter thought this was some sort of
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From page 141... ...
nothing. However, von Karman got wincl of this plan from Rossby, who toIcl him that the Meteorology Department at CaTTech was inadequate, since its heacI, a young assistant professor, was more commercially than scientifically incTinecI.
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From page 142... ...
not only from place to place but from time to time, leaching physicists to speak of the secular variation in the earth's magnetic field. In the first half of the nineteenth century, the famous Gottingen mathematician, Gauss, showed that if one knows the magnetic field over all of the earth's surface the field can be mathematically diviclect into a part whose sources are inside the earth anct a part whose sources are outside.
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From page 143... ...
Although Larmor vaguely suggested in 1919 that the earth's magnetism might be explainecl along these lines, not a single article appeared about it in the intervening years. The likely explanation for the total absence of papers on the subject is that the limited number of those qualified to handle the solution of problems of theoretical physics was absorbed by the two main streams of inquiry then existing in physics, namely relativity and quantum mechanics.
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From page 144... ...
of fluicI iron in the core, which was 0.03 cm/seconcI. He also clerivecl an important formula for predicting the strength of magnetic fields in celestial objects.
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From page 145... ...
Von Neumann listened with interest but, like everyone else, refusec! to believe that magnetic fields could be created by fluid!
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From page 146... ...
Walter protested, mainly against the military way of doing things, but was toicl this was war and he hacI to obey orders. He was assigned to the quartz crystal (livision, one of the largest and busiest branches of the Signal Corps Laboratories.
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From page 147... ...
to a wrong distance. Walter wrestIecl with the problem for some time without success, when he was told it was to be transferred to the Radio Wave Propagation Committee of the National Defense Research Committee.
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From page 148... ...
At Utah he gradually wound up teaching a comprehensive set of courses in theoretical physics, with the exception of quantum mechanics, which was taught by the most distinguished member of the faculty, the theoretical chemist Henry Eyring. In an earlier discussion with John von Neumann, Walter had expressed the desire for a small inexpensive computer.
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From page 149... ...
This dynamic process embocTiecT the advance in un(lerstancling in physical science, but it seemed
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From page 150... ...
Walter decided early cluring his tenure in Salt Lake City that he had risen as high as he could in an academic career short of moving to a more prestigious university. To do so would require that he specialize in only one of the several scientific fields in which he had become competent, in orcler to remain on top in one of the fields.
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From page 151... ...
However, about this time Walter hearct from Harry Hess, chairman of the Geology Department at Princeton, with an offer of a professorship in geophysics. Hess was the in(lividual among geologists who above all took Alfred Wegener's theory of continental drift seriously.
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From page 152... ...
There was no grand edifice, but there was evidence of a general unity of pattern in organic nature. Walter felt that the situation in our age is uniquely propitious for developing a basic theory of organisms because there was, for the first time, an altogether coherent abstract scheme, quantum mechanics, for representing the physical basis of life.
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From page 153... ...
He felt there was a fundamental distinction between the living anct nonliving states, but it hack to be one that did not violate quantum mechanics. Van Neumann's 1932 book Mathematical Foundations of Quantum Mechanics demonstrated that all ensemble averages of physical quantities obey clifferential equations of a simple kincI; that is, their change in time is causally determined.
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From page 154... ...
Through all this time he was unbelievably generous with his time, writing extensive expositions of his biological thought and general philosophy, often in response to naive questions of a pragmatically trainee! biologist.
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From page 155... ...
The closeness of energy exchange in biochemical reactions to thermal noise is necessary for the clecision-making ability of the organism, allowing it to choose between available states without need for more than a minimal supply of energy. This condition contributes to what Walter called the fragility of the living state, defined as the capacity of the system to respond with large-amplitucle changes to small perturbations.
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From page 156... ...
Walter to formulate a holistic set of principles to represent the living state. These principles are not scientific laws in the usual sense since they are not clerivable from the mathematics of quantum mechanics.
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From page 157... ...
The patterns of inorganic systems repeat themselves over and over again ace infinitum, while those of each organism are unique. The selection of a relatively small number of organisms from the immense number of possibilities allowed by quantum mechanics is a primary expression of biological order and is the scientific counterpart of the term "creativity" used in ordinary language.
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From page 158... ...
In other words, operative symbolism is not necessary to the clevelopment of the postulational system of the first three principles that can c30 away with the conceptual clifficulties and internal contradictions that always appear in any purely mechanistic interpretation of organic life. The informational system of organisms is therefore postulated to be clualistic; on one level it is mechanistic in the operation of the genetic code; on the other level it is holistic, involving the entire cell or organism.
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From page 159... ...
Despite the difficulties, his thought has found strong support from a few outstanding biologists such as Leslie Foulds and Paul Weiss. It has also met with approval from some notables among theoretical physicists, including Pauli and Wigner, and from the information theorist L
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From page 160... ...
All clepends on the initial state of the cells and the perturbations to which they are subjected. On a personal note, his philosophical analysis liberated me from the recluctionist strictures that clominate biological thought anc!
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From page 161... ...
Frederick Seitz, formerly president of Rockefeller University, contributed his thoughts on Walter's biological work. Most of the section on that work was derived from Walter's published biological writings and from his extensive correspondence with me between 1981 and 1991.
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From page 162... ...
62 BIOGRAPHICAL MEMOIRS HONORS 1932 Research Prize of the German Physical Society 1957 Member, National Academy of Sciences 1971 John A Fleming Medal, American Geophysical Union 1972 Fellow, American Academy of Arts and Sciences 1977 Gauss Medal, Braunschweig, Germany, (200th Anniversary of Gauss's birth)
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From page 163... ...
WALTER M ELSASSER SELECTED BIBLIOGRAPHY ATOMIC AND NUCLEAR PHYSICS 1925 Bemerkungen zur Quantenmechanik Naturwissenschaften 13:711.
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From page 164... ...
112:344. THEORETICAL BIOLOGY 1958 The Physical Foundation of Biology, An Analytical Study.
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From page 165... ...
WALTER M ELSASSER 165 1981 Principles of a new biological theory: a summary.
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