 Salmon addressed simultaneity in other writings, including the article “The Philosophical Significance of the One-Way Speed of Light” (1977c) which contains a defense of simultaneity’s conventionality, dating back to Einstein and argued for in detail by Reichenbach (1928 [1957]). After surveying a number of experimental methods devised for the measurement of the speed of light, from Galileo to J. Bradley, H.L. Fizeau, and J.L. Foucault, Salmon went on to discuss synchrony, arguing that a conventional element is involved in all of such accounts. Since simultaneity rests on synchrony and ultimately on the one way speed of light, by showing that the latter cannot be ascertained experimentally Salmon intended to “give substance to the abstract conventionality issue” (Salmon 1977c: 255), namely to Einstein’s claim that the relation between the speed of light in two different directions is not a matter that can be established empirically, but only by convention.