“Two Experiments that ‘Proved’ Relativity” is Chapter 2 of The Golem: What Everyone should Know about Science. This prize-winning book of essays by the sociologists Harry Collins and Trevor Pinch is at the center of an ongoing debate between scientists and those who study science. In Chapter 2, Collins and Pinch use examples from the history of relativity to show the lay reader how they believe science reaches its conclusions. Here I use their essay to show readers of Physics Today how I believe Collins and Pinch reach theirs.

The two experiments are the Michelson–Morley experiment and the Eddington solar eclipse expedition of 1919. I learned a lot about both from Collins and Pinch, but I found unconvincing the lessons about the nature of science they draw from these studies of relativity. I focus on their treatment of the Michelson–Morley experiment, and how it bears on the acceptance of special relativity by the scientific community.

The presentation of relativity in The Golem starts with a peculiar statement of the principle of the constancy of the velocity of light: “Einstein's insight [was] that light must travel at the same speed in all directions.”

This is the kind of simplification anyone might make in presenting a technical matter to the lay reader. But this particular reformulation of the postulate that the speed of light is independent of the speed of the source also happens to reinforce the view that Collins and Pinch develop—that doubts about the Michelson–Morley result put at risk the logical foundations of relativity.

The lay reader is told little about the actual content of special relativity. Time dilation and length contraction are briefly mentioned. The inclination everybody has on a first hearing—to regard these phenomena as outlandish—is heightened by qualifications such as “if Einstein's ideas are correct” and “if the theory is correct.” To this touch of skepticism Collins and Pinch add a dash of moral indignation by also mentioning the “sinister” mass–energy relation and the explosion of the atomic bomb. The bomb is cited as an incontrovertible piece of evidence for the validity of relativity. No other compelling evidence is offered.