Abstract
It has been widely held that presentism cannot easily accommodate Einstein’s Special Theory of Relativity (SR) account of the relativity of simultaneity because presentism privileges successively unique times ontologically. Recently Brogaard and Marlow (Analysis 73:635–642, 2013) argued that presentism does not deserve the attribution of this defect because it may well be that Einstein’s account of the relativity of simultaneity is defective, leaving it open to establishing a view of absolutist simultaneity friendlier to presentism. Specifically Brogaard and Marlow present an argument against one of Einstein’s most famous accounts of the relativity of simultaneity, and moreover raise doubts about whether Einstein availed himself of absolutist frames in some of his explanations of relativity. I will dismiss both of these charges, and thus argue that the complaint against presentism from SR stands.
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Notes
See the many references in Brogaard and Marlow (2013, p. 641). Throughout this paper “the present” as used by tensists will be taken to mean any ontologically closed and privileged class of events that are transitively simultaneous either as determined by Einstein’s empirical method of determining simultaneous events in an inertial frame (Pais 1983, p. 142) or by stipulation of forming a spacelike surface of such events in flat spacetime.
Brogaard and Marlow prefer the term “tensism” to stand for any view that ontologically privileges “an objective, ever-changing “now” that typically coincides with our phenomenal experiences of the present” (Brogaard et al., p. 636). I shall stick with the more familiar term “presentism” even if it is more restrictive than tensism, for any conclusion in this paper equally applies to any such tensist view. I thank Berit Brogaard for clarifying my grasp of tensism in correspondence.
I note that this presentation of Einstein’s thought experiment reverses the positions of A and B relative to the motion of the train as Einstein assigned them (Einstein 1951, p. 25). However, in their own “causal” version of the thought-experiment, the positions of A and B are consistent with Einstein’s description.
There are uncertainties here about which frame’s measurement of “two light-seconds” of distance the authors are employing due to the relative contraction of length with respect to who is taken to be the moving or at rest, but my criticism will not require pursuing that problem.
These points are also indirectly made in reply to Brogaard and Marlow (2013) by Manson (2014) and Muller (2014). However, neither of these replies emphasizes the point I make here that the final objective truth of the relativity of simultaneity is only demonstrated by comparative evaluation of different frames of reference that alternate between what is explained from the perspective of a frame of reference. One crucial part of Einstein’s (1951) account is that a narrative about simultaneity from one inertial frame is reversible from another explanatory perspective “vice versa (relativity of simultaneity)” (1952, p. 26, Einstein’s emphasis). That may be just five words, but they collectively state the objective truth of the relativity of simultaneity.
I am making Einstein’s assumption that causality requires before-and-after occurrences of particular events of cause and effect and thus always falls within or on some forward or backward lightcones cast from some particular event (here crucially the physical process at B). The event at B will express that causal influence from A in its forward timelike cone and thus token a causal process for all possible observers.
By hypothesis the process that produces the flash at B would have to precede observation at B by some slight interval.
Brogaard and Marlow (2013) cite, for example, a letter from Einstein to Lorentz in 1916 that seems an endorsement of an absolute-rest aether (Brogaard and Marlow 2013, p. 639). But it is clear that despite fundamental disagreements about relativity, Einstein and Lorentz had a long-term amicable friendship (Pais 1983, pp. 166–167). Perhaps this was a case of rapprochement on Einstein’s part rather than real agreement. Letters do not have the authority about content as bestowed by peer-review, after all.
References
Brogaard, B., & Marlow, K. (2013). Is the relativity of simultaneity a temporal illusion? Analysis, 73, 635–642.
Cohen, M. (1989). Simultaneity and Einstein’s Gedankenexperiment. Philosophy, 64, 391–396.
Cohen, M. (1992). Einstein on simultaneity. Philosophy, 67, 543–548.
Cohen, M. (1995). Simultaneity: A composite rejoinder. Philosophy, 70, 587–589.
Einstein, A. (1951). Relativity: The special and the general theory (15th ed., pp. 25–26). New York: Crown Publishing.
Manson, D. N. (2014). The relativity of simultaneity is not a temporal illusion. Analysis, 21, 234–236.
Muller, F. A. (2014). The relativity of simultaneity is not a temporal illusion. Analysis, 21, 232–233.
Pais, A. (1983). ”Subtle is the Lord”: The science and the life of Albert Einstein. Oxford: Oxford University Press.
Shadowitz, A. (1968). Special relativity, 26. New York: Dover Books.
White, V. A. (1991). Cohen on Einstein’s simultaneity Gedankenexperiment. Philosophy, 66, 245–246.
White, V. A. (1993). Relativity and simultaneity redux. Philosophy, 70, 401–404.
White, V. A. (1996). Picturing Einstein’s train of thought. Philosophy, 71, 591–594.
Acknowledgments
I am indebted to Berit Brogaard for correspondence about and detailed remarks on drafts of this paper.
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White, V.A. Presentism and Einstein’s Train of Thought: Reply to Brogaard and Marlow. Erkenn 80, 1023–1029 (2015). https://doi.org/10.1007/s10670-014-9695-9
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DOI: https://doi.org/10.1007/s10670-014-9695-9