" For [Wolfgang] Pauli the central problem of electrodynamics was the field concept and the existence of an elementary charge which is expressible by the fine-structure constant ... 1/137. This fundamental pure number had greatly fascinated Pauli, .... For Pauli the explanation of the number 137 was the test of a successful field theory, a test which no theory has passed up to now. "

― Wolfgang Pauli , Pauli Lectures on Physics: Volume 1, Electrodynamics (Lectures on Physics 1)