If so is there a published paper or even an informal letter where he said as much?
$\begingroup$
$\endgroup$
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
9
A web search for "einstein" "speed of light" "not a fact of nature" only turns up M Slavov, "Time as an Empirical Concept in Special Relativity" (2019). Slavov cites Wesley C. Salmon, "The Philosophial Significance of the One-Way Speed of Light," Noûs 11, no. 3 (September 1977): 253‒292, at 254. Salmon wrote
From the standpoint of classical physics, as well as simple common sense, it would seem that the equality (or inequality) of the speeds in the two opposite directions is a fact of nature. [...] Einstein seems [...] to be claiming that the relation between the speeds in the two different directions is not a matter of fact at all—rather, it must be established by means of a convention.
citing Einstein's original 1905 paper, which in German said
Es ist aber ohne weitere Festsetzung nicht möglich, ein Ereignis in A mit einem Ereignis in B zeitlich zu vergleichen; wir haben bisher nur eine „A-Zeit“ und eine „B-Zeit“, aber keine für A und B gemeinsame „Zeit“ definiert. Die letztere Zeit kann nun definiert werden, indem man durch Definition festsetzt, daß die „Zeit“, welche das Licht braucht, um von A nach B zu gelangen, gleich ist der „Zeit“, welche es braucht, um von B nach A zu gelangen.
English translation by DeepL, which I think is accurate:
However, it is not possible without further definition to compare an event in A with an event in B in terms of time; so far we have only defined an "A-time" and a "B-time", but no "time" common to A and B. The latter time can now be defined by establishing by definition that the "time" it takes for light to travel from A to B is equal to the "time" it takes to travel from B to A.
I think the wording "[not] a fact of nature" is Salmon's, but Einstein did write something to that effect.
-
1$\begingroup$ An alternative to using DeepL would have been to use the translation that is available on wikisource: On the electrodynamics of moving bodies In this particular case the DeepL translation seems to be quite adequate. Actually, in the DeepL translation the italics font for the words durch Definition is transcribed, whereas the corresponding words in the wikisource version are not in italics font. $\endgroup$– CleonisCommented Aug 8 at 22:27
-
$\begingroup$ Einstein published five papers in 1905. The given quote seems to be from the fourth, about special relativity. I'm having trouble reconciling that with the description "Einstein's original 1905 paper." His first 1905 paper was about the photoelectric effect, which was also the subject for which he was awarded the Nobel prize, so that was not inconsequential. $\endgroup$ Commented Aug 9 at 20:43
-
1$\begingroup$ @JohnBollinger given the question is about relativity, I'd assume the paper about relativity was meant, not some other one. But feel free to suggest an edit to make it clearer. $\endgroup$ Commented Aug 10 at 2:58
-
2$\begingroup$ @Hilmar That video has prompted dozens of questions from confused viewers on the Physics SE and Astronomy SE since it was posted in 2020. In my opinion he doesn't understand Einstein's point at all, and the video has misled millions of people. I wrote about it in this answer. $\endgroup$– benrgCommented Aug 10 at 20:16
-
1$\begingroup$ @Hilmar About the Veritasium video. That video offers a muddled exposition, in my opinion. The point he is trying to make is understandable only for people who have already absorbed the subject. About what I think is problematic: the issue of conventionality of relativity comes up exclusively in the context of relativity of simultaneity. On the other hand: in the context of newtonian space and time there is no relativity of simultaneity, therefore no conventionality of simultaneity. In the video the concept of Minkowski spacetime is touched on implicitly, but that is not enough. $\endgroup$– CleonisCommented Aug 12 at 9:00