Letters

Millikan, Einstein, and the Birth of Relativity   (4 letters)

The orginal 1899 photo of J. J. Thomson, discussed in the letter by Roger Stuewer, and (inset) his left hand as it appeared in the version that Millikan published in 1906.

Everyone can appreciate the noble impulse to republish Millikan's 1949 article on Einstein and Millikan's praise of Einstein on his 70th birthday. Unfortunately, however, although Millikan had many virtues, fidelity to history was not one of them.

Convinced of the primacy of experiment, Millikan asserts that Einstein took the Michelson-Morely experiment "as an established experimental fact" and from it drew "its inevitable consequences. Thus was born the special theory of relativity." Gerald Holton established decades ago, however, that the Michelson- Morely experiment exerted no significant influence on the genesis of special relativity in Einstein's thought.

Millikan argues from a similar empiricist stance, though less egregiously, for the origin of Einstein's theory of Brownian motion, but when he turns to Einstein's paper on "photoelectric stopping potentials," he again falsifies history. In 1949, two years after Lenard had died an unrepentant Nazi, Millikan judiciously avoided citing Lenard's 1902 experiments as the origin of Einstein's light-quantum hypothesis, but he made that connection in his 1923 Nobel Lecture, which he quoted verbatim in his 1950 Autobiography. Martin J. Klein showed decades ago, however, that Einstein's arguments for light quanta were based on the second law of thermodynamics in its statistical interpretation, and that Lenard's experiments constituted only one of three different kinds of experimental evidence that Einstein cited in support of it.

Moreover, by referring to Einstein's paper as being on "photoelectric stopping potentials," and by discussing his own 1915 experiments, Millikan laid claim to confirming Einstein's photoelectric-effect equation and consequently Einstein's light-quantum hypothesis. Indeed, in his Autobiography Millikan stated explicitly that in 1915 he thought that his experiments had "proved simply and irrefutably" that Einstein's equation "scarcely permits of any other interpretation than that which Einstein had originally suggested, namely that of the semi-corpuscular or photon theory of light itself." I invite everyone, however, to read Millikan's original paper, where Millikan argues precisely the opposite, namely, that his confirmation of Einstein's equation meant that it had to be interpreted along semiclassical lines, and that it did not confirm Einstein's light-quantum hypothesis.

Millikan's 1949 article thus perpetuated—and its republication now has further perpetuated—historical myths that still seem to be quite widespread. Millikan was more on target at the end of his article when he praised Einstein's "greatness of soul and keenness of intelligence and understanding rarely found in the history of mankind." Einstein demonstrated those qualities once again in 1949 when he declined to challenge Millikan's description of the content and significance of his three great papers of 1905.

I have discovered an amusing instance and photographic proof of what I have come to call Millikan's philosophy of history: "If the facts don't fit your theory, change the facts." There exists a picture taken in 1899 of J.J. Thomson in his study at home in Cambridge in the book, J.J. Thomson and the Cavendish Laboratory [London: Nelson, 1964, p.53]. In 1906, Millikan reproduced this picture in A First Course in Physics, but he carefully etched out the cigarette in Thomson's left hand. Millikan presumably did not want to corrupt young physics students, and therefore thought he had best change the moral tenor of the great physicist's image. Millikan, in short, was absolutely shameless in his falsification of history.
Roger H. Stuewer
Minneapolis, MN

References:
Holton, Isis 60, 133-197 (1969). 

The Autobiography of Robert A. Millikan (New York: Prentice Hall, 1950), p. 102.

Klein, The Natural Philosopher 2, 59-86 (1963).

Millikan, Autobiography, pp. 101-102.

Millikan, Physical Review 7, 355-388 (1916).

It was interesting to reread Robert Millikan's 1949 tribute to Einstein (APS News, January 2004.) We should be reminded, however, that Millikan's version of the genesis of special relativity is grossly inaccurate. According to Millikan, Einstein was led to his theory directly by the null result of the Michelson-Morley ether-drift experiment, but that scenario is almost surely untrue.

There is some question as to whether Einstein even knew of Michelson's result when he wrote his 1905 relativity paper. In a 1950 interview, Einstein told Robert Shankland that he became aware of the result through the writings of Lorentz, but only after 1905! "Otherwise", he said, "I would have mentioned it in my paper."

When Shankland raised the question again two years later, Einstein gave a different response. "This is not so easy", he said. "I am not sure when I first heard of the Michelson experiment. I was not conscious that it had influenced me directly during the seven years that relativity had been my life."

He added that in the years 1905-1909 he thought a great deal about Michelson's result. He then realized that he had also been conscious of the result before 1905, partly from the papers of Lorentz and more because he had "simply assumed this result of Michelson to be true."!

Abraham Pais, who knew Einstein well and wrote his scientific biography, was certain that Einstein did know about Michelson's experiment before 1905. He points out that Einstein was over seventy and in poor health when he spoke to Shankland; at the first interview he probably did not remember that Michelson's experiment is discussed in Lorentz's 1895 monograph, the famous "Versuch", which Einstein had definitely read before 1905.

Even if Einstein was aware of Michelson's result, however, we must accept his assertion that it was not a major motivating factor in his discovery of relativity. He repeatedly uses terms like "negligible", "indirect", and "not decisive" to describe the influence of Michelson's experiment on his thinking. In a penetrating analysis of the issue, Gerald Holton concludes that "the role of the Michelson experiment on the genesis of Einstein's theory appears to have been so small and indirect that one may speculate that it would have made no difference to Einstein's work if the experiment had never been made at all." In the light of this assessment, Einstein's achievement looms all the more remarkable.

If Einstein was not guided by the result of Michelson's experiment, how then did he arrive at relativity? That is the intriguing question. Einstein's paper provides little guidance. In it the postulate of the constancy of the velocity of light is presented with no explanatory remarks or motivation, almost as though it were a routinely accepted proposition instead of a daring departure from conventional notions.

In an autobiographical essay written in 1949, Einstein describes a paradox that had occurred to him at age sixteen. If one pursues a beam of light at the velocity c, he notes, one should observe a spatially oscillatory electromagnetic field at rest. But there seems to be no such thing, either on the basis of experience or according to Maxwell's equations.

"From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest." The seed of the theory of relativity had evidently been planted when Einstein was only sixteen years old! The idea that light has the same speed for all inertial observers, so difficult for an ordinary mind to accept, seemed quite natural to Einstein. He was fully prepared to accept it even without strong experimental evidence.

In the Shankland interview, Einstein said that the experimental results that had influenced him most were the observations on stellar aberration and Fizeau's experiment on the speed of light in moving water. "They were enough", he said. This assertion is perplexing because both stellar aberration and the result of Fizeau's experiment are readily accounted for without relativity. Fizeau in fact thought he had confirmed Fresnel's ether drag theory.

Millikan emphasizes that modern science, unlike Greek philosophy and all medieval thinking, takes as its starting point well-authenticated, carefully tested experimental facts. This is almost universally true, but relativity appears to be one of the few exceptions. It is easy enough to understand Millikan's desire to give Michelson credit. He was an experimenter and he greatly admired Michelson, under whom he had worked as a young man. The scenario he described was one he wanted to believe. But the true genesis of special relativity apparently lay in Einstein's inspired intuition.

As is well known, Einstein's paper contains no references whatever. It does refer to "unsuccessful efforts to discover any motion of the earth relative to the 'light medium,' " without identifying any of those efforts. The Michelson-Morley experiment was only one of them. Einstein's first reference to the M-M experiment was in a review article he published in 1907.
Leo Sartori
Lincoln, NE

References:

 A. Pais, Subtle Is the Lord (Oxford: Oxford University Press, 1982), 116.

G. Holton, "Einstein, Michelson, and the Crucial Experiment", a chapter in his Thematic Origins of Scientific Thought (Cambridge: Harvard University Press, 1988.) See also G. Holton, "Einstein and the Crucial Experiment", American Journal of Physics 37 (1968), 968-982.

A. Einstein, "Autobiographical Notes", in Albert Einstein: Philosopher-Scientist, ed. P.A. Schilpp (Evanston: Harper Torchbook, 1949), 53.

R.S. Shankland, "Conversations with Albert Einstein", American Journal of Physics 31 (1963), 47-57.

The relativistic correction to the classical aberration formula is only about 10-7 seconds of arc, much too small to be detected.

In the January 2004 edition of the APS News, an article by Robert A. Millikan has been reprinted which is considered to be "especially noteworthy because it describes the content and significance of Einstein's three great papers of 1905". In this article, Millikan writes that "the special theory of relativity may be looked upon as starting essentially in a generalization from Michelson's experiment." Regarding the null effect of the Michelson-Morley experiment, Millikan quotes Einstein as calling out to us all, "Let us merely accept this as an established experimental fact and from there work out its inevitable consequences".

But there is no evidence that Einstein ever made such a remark. On the contrary, in his 1905 paper "On the Electrodynamics of Moving Bodies", Einstein did not refer to the Michelson-Morley experiment or to any other papers. Instead, Einstein motivated his "principle of relativity" by calling attention to "the reciprocal electrodynamic action of a magnet and a conductor", pointing out that the "observable phenomenon" (the current induced in the conductor) depends only on the relative motion of the magnet and the conductor.

In 1920, Einstein recalled that "in setting up the special theory of relativity, the following...idea about Faraday's electromagnetic induction played a guiding role. According to Faraday, relative motion of a magnet and a closed electric circuit induces an electric current in the latter. Whether the magnet is moved or the conductor doesn't matter; only the relative motion is significant...The phenomena of electromagnetic induction...compelled me to postulate the principle of relativity." And again, in 1952, Einstein wrote that "My direct path to the special theory of relativity was mainly determined by the conviction that the electromagnetic force induced in a conductor moving in a magnetic field is nothing other than an electric field. But the results of Fizeau's experiment and the phenomena of aberration [discovered by James Bradley in 1727] also guided me."

Einstein's reticence to acknowledge the Michelson-Morley experiment has been well documented. In a letter to the historian F.C. Davenport, written a year before his death, Einstein consistently remarked that "in my own development, Michelson's result has not had a considerable influence. I even do not remember if I knew of it at all when I wrote my first paper on the subject (1905). The explanation is that I was, for general reasons, firmly convinced that there does not exist absolute motion, and my problem was only how this could be reconciled with our knowledge of electrodynamics. One can therefore understand why in my personal struggle, Michelson's experiment played no role, or at least no decisive role."

One would hope that next year, while commemorating Einstein's monumental 1905 achievements, long standing myths like the one propagated by Millikan's article, that Einstein was motivated by the Michelson-Morley experiment to discover the special theory of relativity, should finally be dispelled.
Michael Nauenberg
Santa Cruz, CA

Robert Millikan writes about Einstein's character being an example of "the distinguishing feature of modern scientific thought...that takes...as its starting point...experimental facts."

It's true that the Michelson & Morley experiment took place well before Einstein published his theory; but, as Polanyi says he confirmed with Einstein himself, the theory of relativity was not based on news of that experiment but on entirely independent thought begun before it: "Its findings were, on the basis of pure speculation, rationally intuited by Einstein before he had ever heard about it" (page10 in Personal Knowledge). The positivistic account, says Polanyi, is therefore "an invention" and "the product of a philosophical predjudice": "When Einstein discovered rationality in nature, unaided by any observation that had not been available for at least fifty years before, our positivistic textbooks promptly covered up the scandal by an appropriately embellished account of his discovery."

Einstein said that Ernst Mach's Die Mechanik in ihrer Entwicklung (1889) had a "profound influence" on his thought. This influence was a positive force in the development of relativity theory, but the irony is that it was not the sort of influence Mach himself could have imagined having. It grew out of Mach's objection to Newton's idea of absolute space, on the ground that since it could not be tested by experiment it was meaningless.
Doug Mounce
Seattle, WA

Need Guidelines For Objective Evaluation

I am surprised at David Thouless's assertion that scientific ethics is culture-dependent. Culture certainly impacts the practice of science: our work-hours and work-habits, our interpersonal relationships, our demeanour, our informal interactions. Such factors often influence which students get noticed as early achievers, which early researchers get propelled on the scientific fast-track, which senior researchers break in more forcefully to have the last say in a group discussion. But they can, and should, be judiciously screened out by any physicist during the objective process of academic evaluation and scientific review.

Are we physicists doing a sufficiently conscientious job in this regard? What I believe is necessary is not so much a longer set of rules on eliminating conflicts of interest. This has the problem that, in an era of specialization, it often leaves nobody adequately competent to review a given grant proposal or manuscript. Instead, we need a tool kit of guidelines on how to evaluate objectively—screening out information about the candidate that should be clearly irrelevant from the viewpoint of professional ethics. I would urge the APS to begin the process of formulating consensus on such guidelines. Accurate and objective evaluations are central to the continued health of our field.

Finally, I strongly support the APS's new guideline that a submission be reviewed by all listed co-authors. Co-authorship can cover a variety of contributions: a key idea, helpful physical intuition, calculation or data analysis, significant scientific programming assistance, coherent pedagogical presentation of previous work, or, best of all, equal research contribution. (Not management. If relevant, as in a large project, that belongs with the acknowledgment of financial and administrative support item.) The distinctions in author contribution are usually spelled out in peer review letters, or in informal exchange.

As a junior postdoc, I remember including co-author names on my conference proceedings even when I was both sole presenter, and sole author of the written-up talk. This was unnecessary, possibly stemming from a lack of confidence. This could well be a cultural issue: I'm Indian-educated, and female. Of course, I had the submission reviewed by my senior co-author. This was no ethical dilemma. But I have also had the reverse experience of a fellow postdoc publicly posting the proceedings of a talk listing all four co-authors, but without our prior review. The APS guideline prevents such professional embarrassments: I could have simply removed my name from what I thought a totally inaccurate presentation of our research goals and results.
Shyamoli Chaudhuri
Bellefonte, PA

Huey is Screwy

I enjoyed the Zero Gravity in January's APS News—except that Huey screwed up at the end, thinking that he was pitching from first base, rather than from the mound (60' 6" from the plate).
Kermit Smyth
Darnestown, MD

Hydrogen Economy: Pleasant Ideas vs. Basic Science Constraints

In "Revolutionary Breakthroughs Needed for Hydrogen Economy" (APS NewsNovember 2003), Andrew Lenard's response (APS News January 2004) points out that contrary to representations or public impressions, hydrogen is not an energy source. It can be created only by consumption of a still greater amount of an existing energy form. That is fundamental thermodynamics. That is not the only basic problem with the "hydrogen economy". As scientists and educators, must we not point out other prevailing misconceptions (or ignorance?) of fundamental and limiting laws of nature?

The interest in hydrogen as a fuel arose decades ago from environmental pollution concerns, now specifically directed to prevent continued increase of global warming by continued addition of some 2.5 x 10⁹ tons/year of CO₂(and more every year). If hydrogen fuel was generated from existing fossil energies, this would conveniently concentrate the task of CO₂ removal to the location of the hydrogen production facility. Such technology for large-scale and permanent capture is conveniently termed CO₂ "sequestration", but it does not exist. It offers challenges and research support for innumerable ideas in many branches of science, technology and business. It behooves the scientist community to point out that very fundamental physical and chemical science and arithmetic seriously handicap its accomplishment.

Physically pumping high concentrations of CO₂ into selected deep sea or geological locations is possible but permanence of such disposal would be variable and uncertain for different locations. It would be similar to 'hiding' in a remote location with duration poorly predictable for our descendents or ourselves.

Any process system to permanently capture CO₂ requires its transformation to a stable solid product on earth. Thermodynamics requires a reaction partner of sufficient chemical free energy. There are no large quantities of such material readily available. Some minerals such as serpentine (MgO) could form solid carbonates. But this would require locating, mining, transporting, activating the mineral, processing the CO₂ reaction and burial of the products in amounts greater than some 2.5 x 10⁹ tons per year. The entire operation would itself consume additional fuel energy and further increase the amount of CO₂ to be eliminated.

Many proposed methods of 'sequestration' involve generation of added biological growth in the marine or terrestrial ecosystem. The great kinetic complexity of the huge number of interactive phenomena makes it difficult to determine the course and ultimate result of any proposed intervention. However, basic thermo- dynamics, kinetics and arithmetic dictate definable limits of performance for the overall system regardless of detail.

Any biological growth will consume atmospheric CO₂ during its life cycle. Then, CO₂ is returned by decomposition (oxidation, directly or via 'food' chains involving biological intermediates, burning, etc.), with only a minor fraction 1/n of permanent earthly residue remaining. Thus 'sequestration' is achieved initially to the extent new growth is added. However, as steady state is achieved, only 1/n of added growth remains 'sequestered'. Therefore, capture of a magnitude of some 10⁹ tons per year would require addition of n x 10⁹ tons of biological-maritime or terrestrial-living matter. This is an objective of rather fantastic magnitude.

In any event, how can we create additional living biochemical matter, anyway? It requires photosynthesis, i.e. solar energy. We cannot increase solar energy flux. Can we increase its effectiveness? In terrestrial agriculture we use "fertilizers".

They are carriers of additional chemical free energy. For terrestrial use we produce them using fossil fuel energy. (Remember, fertilizers have occasionally been used to make explosives). We also produce fertilizer by photosynthesis, by dedication (rotating) land acreage, i.e. a fraction of available solar input received, to grow nitrogen-fixing legumes to subsequently fertilize the soil for the next harvest.

Marine life is also stimulated by marine photosynthesis of high chemical energy (nitrate) 'fertilizers'. But can we increase total photosynthesis of the biological products and the energy intermediates we call 'fertilizers' from the same surface of solar radiation received? This does present a very challenging fundamental research question: Can we catalyze biological photosynthesis, i.e. find a catalyst that will not be consumed itself?

Creation of a "hydrogen economy" is a fascinating objective for funding and investigation of innumerable ideas. However, as long as fossil fuel energy must be used to generate the hydrogen, the very basic difficulty, if not impossibility, is the return of the vast amount of carbon extracted and oxidized by Homo sapiens back to permanent fossil status on earth.
Paul B. Weisz
State College, PA.

Use Renewable Energy to Make Hydrogen

Andrew Lenard in his letter in the January issue of APS News is correct in stating that hydrogen obtained from hydrocarbons would gain nothing, in fact would result in a net loss of available energy and would do more damage to the environment than a direct use of these hydrocarbons. Apparently he does not consider producing hydrogen or electricity by solar cells, wind energy or other renewable sources. At the present time these methods are more expensive but with mass production and improved engineering the cost could be reduced.

How does one put a price tag on the needless waste of human lives resulting from wars and other aggressive actions to insure the flow of oil?
Clarence M. Cunningham
Stillwater, OK