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Dingle’s Argument And Question About Special Relativity

Professor Herbert Dingle was one of the most respected relativists of his era – at least until he started asking questions that no one could answer. As discussed on the Report page, Dingle became involved in a much publicized debate about the Twin Paradox and his name became intimately linked with that paradox. However, Dingle soon took the essence of the Twin Paradox and created a very simple question about Special Relativity. He was to pursue his questioning of Special Relativity for decades. Many relativists heaped scorn and ridicule on Dingle and his question, but no answer was received.

In his book, "Science At The Crossroads", Dingle, on page 7, gave the simple, basic question – see below:


“According to the theory, if you have two exactly similar clocks, A and B, and one is moving with respect to the other, they must work at different rates (a more detailed, but equally simple, statement is given on pp. 45-6, but this gives the full essence of the matter), i.e. one works more slowly than the other. But the theory also requires that you cannot distinguish which clock is the 'moving' one; it is equally true to say that A rests while B moves and that B rests while A moves. The question therefore arises: how does one determine, consistently with the theory, which clock works the more slowly? Unless this question is answerable, the theory unavoidably requires that A works more slowly than B and B more slowly than A --which it requires no super-intelligence to see is impossible. Now, clearly, a theory that requires an impossibility cannot be true, and scientific integrity requires, therefore, either that the question just posed shall be answered, or else that the theory shall be acknowledged to be false. But, as I have said, more than 13 years of continuous effort have failed to produce either response.”


Dingle saw that if one could not explain the net proper time difference using Special Relativity’s time dilation equation, then Special Relativity could not be directly describing actual clock slowing, i.e., it could not be directly describing proper time. In time, most of the mainstream quietly came to agree with Dingle regarding his view on the Twin Paradox, but they either did not see or publicize the corollary that, therefore, Special Relativity could not be directly describing proper time.

Further Interpretation

If one contends that a clock cannot accumulate proper time both faster and slower than another clock, then one cannot interpret Special Relativity’s time dilation equation as describing proper time and, hence, cannot interpret it as directly describing what’s occurring physically. Since Special Relativity’s length contraction equation was derived using the same basic logic as for the time dilation equation, an analogous conclusion holds for that equation. It then follows that Special Relativity’s equations for kinetic energy and momentum cannot be directly describing what’s occurring physically. Putting it succinctly, Special Relativity cannot directly describe what’s occurring physically and that includes, given its definition of clock synchronization, its postulate on the speed of light in inertial frames.

Einstein, in his 1905 “relativity” paper, selected a convention for synchronizing clocks. This convention stated that if one sent a light signal from to A to B and it was reflected back to B, then the time for going from A to B would equal the time for going back from B to A. Thus, the time it took for light to go from A to B would be ½ the time for the complete round trip. This convention is consistent with and, in fact, is required by the 2nd relativity postulate that the speed of light is isotropic in all inertial frames. The 2nd postulate and this synchronization convention are, of course, part of the foundation of Special Relativity.

However, Prof. Selleri, in Chapter 5 of his book “Weak Relativity”, notes that professors H. R. Reichenbach and Max Jammer have shown that one can choose the ratio of the time it takes for light to go from A to B to the time for the complete round trip to be any fraction between 0 and 1 and that will yield a theory that is as valid as Special Relativity. Using “e” as the ratio that Einstein chose to be ½, Reichenbach showed that any value for e, where 0 < e <1, would likewise be adequate and could not be considered false. Jammer agreed with Reichenbach and wrote, "The thesis of the conventionality of intrasystemic distant simultaneity ... consists in the statement that the numerical value of e need not necessarily be 1/2, but may be any number in the open interval between 0 and 1, i.e., 0 < e <1, without ever leading to any conflict with experience." None of these choices for e would lead to a theory that described what was happening physically as they would all be based on a premise that was, in general, false.

Hence, the selection of e = 0.5 for all directions in all frames is a convention that does not represent what’s happening physically. For the unique frame where the speed of light is isotropic, the selection of e = 0.5 would be accurate. However, Einstein’s convention simply tries to make every frame simulate the unique frame so, when the conventions of Special Relativity are followed, each observer (erroneously) observes the world as though he were at rest in the unique frame.

It is, therefore, recommended that the physics community seriously consider the construct of a unique physics frame and the associated construction of what’s happening physically in addition to Special Relativity’s description of each observer’s conflicting views.


H. Dingle, Science at the Crossroads (Martin Brian &amp; O'Keeffe, 1972), Downloadable from the World Science Data Base - Click Here

F. Selleri, LA RELATIVITA' DEBOLE La fisica dello spazio e del tempo senza paradossi (Melquiades, Milano 2007-2010) [The online English version, "Weak Relativity" is downloadable.]

H. R. Reichenbach, The Philosophy of Space and Time (Dover, New York, 1958)

H. R. Reichenbach, Philosophie der Raum-Zeit-Lehre, (Berlin, 1928) p. 224

M. Jammer, Concepts of Simultaneity (The John Hopkins University Press, 2006)

M. Jammer. at page 205 of G. Toraldo di Francia, ed., Problems ni the Foundations of Physics (Societa Italiana di Fisica, Bologna and North Holland, Amsterdam, 1979)


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