Is It the Same Result? Replication in Physics

One of the interesting issues in the philosophy of experiment is that of the replicability of experimental results. The scientific community enthusiastically endorses the idea that replication is the scientific “gold standard.” The underlying argument for this is that if an experiment has succeeded in revealing a real phenomenon or accurately measuring a quantity then that success should reappear when the experiment is repeated under the same circumstances or when it is reproduced in a different experiment. There are, however, questions concerning what constitutes a successful or failed replication.

In this paper I will discuss two clear examples of successful replications: The discovery of the Higgs boson and the detection of gravitational radiation. Two failed replications will also be presented: early experiments on the Fifth Force, a proposed modification of Newton’s Law of Gravity; and attempts to measure G, the universal gravitational constant in Newton’s law. More complex episodes in which the success or failure of replication was not clear will also be discussed. These include the strange history of η_+- and experiments on the pentaquark, the case of the disappearing particle.