New York Times, October 26, 1930
Section: Editorial, Page E2, 5833 words
RUSSELL'S REMARK ON THEORY OF ATOMIC STRUCTURE UPHELD; His "Green Cheese" Statement Is Declared to Have Considerable Justification
To the Editor of The New York Times:
Wallace Russell's statement "all modern theories of atomic structure have no more relation to nature than green cheese" should not offend George Soule's friends, for that point of view is held by many of the scholars who tentatively accept the modern theories in lieu of more satisfactory theories, because more satisfactory theories have not appeared. To Einstein himself, the theory of relativity is tentative, and Einstein knows that the theory falls if one deduction does not find experimental check. The Bohr theory was purely tentative, and Bohr himself knew full well that his assumptions were arbitrary and unreasonable, and only to be justified in case the deductions from them gave better approximations to observation than had previously been obtained.
As a matter of fact, the equations of Schrodinger, which so far rest on a purely artificial set of assumptions, have replaced the Bohr concept very largely, for they have "explained" in mathematical language phenomena which could not be obtained from the concept of Bohr.

Less Emphasis Desirable.

Mr. Russell should, perhaps, be slightly less emphatic and leave some room for the possibility that some of the present pictures are actually true, but substantially his criticism is correct. Einstein himself, when he said that "space is eating up matter" meant merely that we have been obliged to attribute in greater and greater measure properties to space in order to justify our equations. Whenever we attribute properties to space, the presumption exists that the phenomena are not understood. The mere increase in this tendency is an indication of the probably departure of modern pictures of nature further and further from the truth. Einstein's theory of relativity did away with the motion of the physical existence of the ether, established originally by the properties which theory required to be given to space, only to replace it in larger measure with other properties.
I wish to criticize the statement "Millikan, Bohr, Rutherford, Langmuir and others of great prominence have proved their theories by experiment", for it gives a serious misconception of the actual state of affairs. Certain definitions must be kept in mind or my objections may be misunderstood. A theory is a mental picture of the universe, or a part thereof, which best accounts and satisfactorily accounts for the known phenomena. To test a theory, we make all the deductions possible from the theory and make experiments to see whether the deductions find a counterpart in nature. The ether-wave theory of light held sway for over a hundred years. From the time of Clerk Maxwell onward it so satisfactorily accounted for phenomena and had so unexpectedly deduced so many unsuspected relationships in physics that it was regarded as an established fact, a true picture of the universe. Yet today very few of the leading physicists believe in an ether at all.

Theories Widely Divergent.

It must be remembered that there are often several sets of assumptions which will yield the same, or indistinguishable, equations for a given set of phenomena. Yet the theories based on these assumptions may give widely divergent pictures of the universe. Bohr's theory gave the spectrum of the hydrogen atom admirably, but never gave a really satisfactory picture of that for any other substance, though several of the deductions were close. Schrodinger's equations, based on quite a different picture of the universe, give the hydrogen spectrum and many others with a wealth of detail. Yet it would be a rash man who would claim that the final picture had been drawn.
The theory of relativity is erected upon the necessity of including in any picture of the universe one stubborn fact. Observations upon bodies in motion, corrected for the motion of the "messenger" upon the ether wave theory of light (which is denied by the theory of relativity), yield quantities which must be transformed according to the Lorentz transformation in passing from a system of coordinates fixed with regard to one observer, to a system of coordinates fixed with regard to another observer in motion relative to the first. A certain set of assumptions has been set up by Einstein, and accepted by others, to account for the existence of the Lorentz transformation. The set of assumptions which appeared most reasonable to Einstein happens to be quite repugnant to the intuitive common sense of mankind. The experimental check of deductions from the theory of relativity, then, do not necessarily prove the truth of the assumptions, as is commonly believed, even by men who should know better, but merely that the fact introduced into the picture of the universe is of more widespread significance than had been previously believed.

As to Light Velocity.

Now I pointed out in a previous letter that the Lorentz transformation is a necessary consequence of any attempt to allow for the velocity of the messenger (for example, light) on the wave theory (fixed ether) if the velocity of light were really to require measurement with regard to the source. If we measure light velocity with regard to the source and not with regard to a fixed ether, we shall obtain different corrected values for our observations and said new corrected observations would transform from one set of coordinates to another set in motion relative thereto by the usual Newtonian transformation.
I pointed out that mathematically one theory was equivalent, in many respects, to the other, but that the picture of the universe was entirely changed. I also pointed out that the choice between Einstein's set of assumptions and mine rests entirely on the outcome of experiments on the velocity of light from moving bodies, and further showed that the assumption of Einstein and others that the velocity of light relative to the observer, assumed to be always observed as constant, irrespective of the motion of the source, was not justified by a critical examination of the experimental data. The velocity of light from a moving source has never been measured.
One more comment. Einstein, Edlington (?), Heyl, DeSitter and possibly others have all developed general theories of relativity. Usually we think only of Einstein's theory as the theory of relativity. Yet Sir James Jeans and other astronomers incline to DeSitter's form of the theory because certain deductions from it fit certain observations on distant nebulae, and such deductions are not obtainable from Einstein's form of the theory. So you see there is considerable justification for that particular remark of Russell's on "green cheese."
EDWARD ADAMS RICHARDSON, Bethlehem, Pa., Oct. 21, 1930.