Testing Experimental Theories: A Bayesian Analysis of Robert Millikan’s Measurements of the Fundamental Electric Charge

Abstract In the early 20th century a controversy arose between Robert Millikan and Felix Ehrenhaft regarding the fundamental electric charge. This controversy began among physicists in the 1910s and has continued among historians and sociologists of science, with doubts persisting that Millikan had confirmed his finding of a unitary charge. While some have argued that the matter was resolved by Millikan’s experiments, others maintain that the claim remains unresolved due to theoretical bias. A method is described to quantitatively compute the probability of the respective theories in Bayesian terms, both in real time, as observations are made, and cumulatively after a batch of experimental measurements were completed. Millikan’s experimental results are modelled as a matrix of theory-experiment co-occurrences and show that Millikan’s findings were conclusive. The applicability of the method to the history of science is discussed. Peer Review https://www.webofscience.com/api/gateway/wos/peer-review/10.1162/QSS.a.494