"In addition to transforming a neutron into a proton and vice versa, the weak force was evidently responsible for the decay of a muon into an electron. ...[W]hen the strange particles were found to decay without s it was realized that the force was more complex than had been posited in Fermi's theory of beta decay. Nevertheless, the fact that aspects of the force could be explained by an electromagnetic formalism implied that these forces shared an underlying symmetry."