This post is for the special “fools, failures and frauds” edition of The Giant’s Shoulders.
The early 20th century was clearly an exciting time to be a physicist. In 1905, Einstein published his special theory of relativity, radically revising human concepts of space and time. In the same year, and the same issue of the Annalen der Physik, Einstein really sparked the “quantum revolution” with his explanation of the photoelectric effect, an explanation that would scramble existing preconceptions of the nature of light and matter and would eventually shake the deterministic foundations of physical theory.
By the teen years of the 1900s, it must have seemed to many physicists that no idea was too crazy to possibly be true! Furthermore, the simplicity and elegance of Einstein’s relativity must have suggested to scientists that the secrets of the universe remaining to be discovered would be of the same sort of “beautifully obvious” form.
One researcher who was seduced by this sort of thinking was Richard C. Tolman. In 1914, he published a paper on a new physical principle that he referred to as “the principle of similitude”. In Tolman’s own words, his principle represented a new form of “relativity of size”, which “provides a very simple and general method for obtaining conclusions as to the form of functional relations connecting physical magnitudes.”
Tolman’s theory was bold, it was powerful… and it didn’t really work out. It is a great example of a failed theory, and even more fascinating because its proponent was no crackpot, and its insights turned out to have some practical use in the end. There’s even a whiff of a conspiracy surrounding similitude, which I will describe at the end of the post!
This post is closely related to the idea of dimensions in physics; if you’re not familiar with this concept, check my earlier post here.