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Herbert Dingle article

First, glad to see you now have a username. It's hard to tell people apart when there are several IP names at one time. You may wish to put something (anything will do) on your user page, and then the links to your name will appear in blue instead of red.

Due to the high noise to signal ratio on the Dingle talk page at the present time, I'll say a few things here. To your question "is time dilation under inertial motion symmetric or asymmetric?", the answer is that it is symmetric, with the caveat that the question isn't very precisely phrased, though I think I know what is being asked. It is true that ${\displaystyle \left({\frac {\partial t'}{\partial t}}\right)_{x}=\left({\frac {\partial t}{\partial t'}}\right)_{x'}}$ to use the phrasing in the detested mathpages article. However, it doesn't follow that special relativity is inconsistent due to that reciprocity. Dingle was in error on that last point (as per vast majority of physicists and per my own understanding of special relativity, linear algebra and group theory). How exactly that fits into the historical debates between Dingle and McCrea, I can't say, because I haven't read them. It's silly that some have labeled this an issue of editors taking sides between Dingle and McCrea, as the article is about Dingle. His claim is clearly wrong. Anyway, enough about that; I don't intend to get into a drawn-out debate.

Yes, there are plenty of details of Dingle's life that should be included in the article. Some of the current wording should also be changed. I agree that the sentence talking about the "commonsense" method is totally unclear. Even the statement that the Dingle-McCrea debates are well-known isn't entirely accurate either, but I couldn't think of a quick way to improve it in my last edit.

Happy editing and try not to take any of it too seriously. Tim Shuba 03:16, 29 July 2007 (UTC)

My reply Herbert Dingle Article Tim,

Thanks for your reply

The question "is time dilation under inertial motion symmetric or asymmetric?", seems pretty straightforward to me, I have taken the wording more or less directly from the wiki article on time dilation, what is it you dont understand? The exact wording there is: "Time dilation is symmetric between two inertial observers", would you prefer that wording?

Unfortunately, I cant find any mention of the equation, you quote, in Einstein's 1905 paper, Dingles book, or McCrae's replies, so I don't how it is relevant. Do you have a reference for this equation so I can see where Dingle used it? However, since we are dealing with a logical inconsistency/contradiction, it cannot be answered by a mathematical proof or by experiment.

The exchange between Dingle and McCrae, should have been straightforward, except that Dingle made the mistake of answering the mathematical irrelevancies put forward by McCrae. In my experience, this is quite a common ploy with mathematicians in an attempt to win an argument. I cant recommend Dingles book as a good read, he does go on a bit, but it does give you an idea of how his argument was dismissed out-of-hand without actually being answered satisfactorily. I'm a bit surprised that you twice state that Dingle was wrong, and yet you havent read letters that passed between him and McCrae. Dingle was not a random crackpot who picked up Einsteins paper one day and decided he knew better, he wrote and collaborated on several textbooks on relativity and wrote the Encycopaedia Britannica section on the subject. He was clearly well respected in this area, over a long period of time. He even discussed it with Einstein, I believe. I would think the least you could do is read what he had to say.

In the meantime, let me summarise briefly, Einsteins paper of 1905 performs a calculation on a 'stationary' clock and a 'moving' clock, and produces the result that the 'moving' clock is ACTUALLY running slower than the 'stationary' clock. This is not just the appearance that it is running slower from the point of view of the 'stationary' clock, but actually showing an earlier time when they are brought together. Dingle's point was simply that, according to the postulate of relativity, either one of the clocks could be considered to 'stationary' and the other 'moving'. Then identical calculations could be performed with the clocks reversed, producing exactly the same result, but now it is the other clock that is running slow. Obviously they cant both be running slower than the other one. This is why I said that no mathematics need be used to disprove this, since before you do any calculating, you have to decide which clock you consider to be stationary and which moving. Einstein calculated the slowing of only one of the clocks but not the other with the roles reversed. Dingles question was simply, why did he pick only one of them? what distinguished this clock from the other? What also has to be borne in mind is that in the section of the paper on length contraction of moving rigid bodies, he stated that this particular effect was reciprocal!, I think you would have to agree that there is an inconsistency there. McCrea in his replies maintained that Einstein's 1905 paper was correct and that slowing of the clock was ACTUAL and asymmetrical, and produced large quantities of equations and spacetime diagrams, to show why the situation was asymmetrical. The current view as I have said before appears to be that the 'moving' clocks only appear to slow down when viewed from the 'stationary' system and that this effect is symmetric. A point, apparently, that Einstein conceded in a book in 1922, although I dont have a reference for this book. This last bit I find baffling, since Dingle didnt mention this book of Einsteins throughout the debate, it surely would have convinced McCrea. Anyhow, I would like to hear your views on this, and also get rid of the mathpages article which I hope you can now see is irrelevant and insulting. BTW do you know who wrote it?

Swanzsteve 05:50, 29 July 2007 (UTC)

Here is a quick follow up to that equation you quoted from the mathpages, this is a quote from McCrea himself: "Dingle has not made any mistake in the algebra..." That doesnt really square with the mathpages, does it? Where did that equation come from?

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