1954/07/01 by Adolf Grünbaum · 32 citations
Mathematics · Physics and Astronomy · #Classical mechanics #Einstein #History and Developments in Astronomy #History and Theory of Mathematics #Observer (physics) #Physics #Quantum mechanics #Relativity and Gravitational Theory #Special relativity #Theoretical physics #Theory of relativity #Time dilation #Twin paradox
paper · doi:10.1086/287347
published in Philosophy of Science 21(3), 249-253 (Cambridge University Press)
openalex publication_date 1954/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22
1. Introduction. The germ of the clock paradox was contained in Einstein's fundamental paper on the special theory of relativity, where he declares that the retardation of a moving clock “still holds good if the clock moves from A to B in any polygonal line, and also when the points A and B coincide.” This remark soon gave rise to a criticism which was to play a prominent role in the discussions of the consistency of the theory of relativity. It was charged that this theory allows the paradoxical conclusion that at the instant of the return of a moving clock U 1 to its point of departure A , the time shown by U l is both earlier and later than the corresponding reading of a clock U 2 which has remained stationary at A during U 1 's journey. Critics based this contention on the following assumptions, for which they claimed the sanction of relativity: (i) The relative motion of U 1 and U 2 is such that the kinematic process seen by an observer on one of these clocks is of the same character as that seen by an observer on the other, and this symmetry allows each of these two clocks to be used as a reference frame from which to describe the motion of the other, and (ii) there is reciprocity between these two reference frames such that in each of them, the moving clock must be slow upon returning to the stationary one.