Wolfgang Pauli after articulating the Exclusion Principle recognized that it was equivalent to electrons behaving according to Fermi-Dirac statistics. He therefore undertook in 1936 to prove that for particles of spin ±½ there could be no more than one particle occupying a state.

Pauli attached great importance to the particle energy being positive. He made some mathematical assumptions which he thought to be innocuous but the validity of which other physicists questioned. One such assumption was that the wave function of a particle can be divided into two parts. (UNDER CONSTRUCTION)

Ian Duck and ,E.C.G. Sudarshan, Pauli and the Spin-Statistics Theorem,, World Scientific, Singapore, 1997.