S'hi

“Realizing its fundamental importance in understanding spectral lines, in atomic physics and in the theory of how light and electrons interact, quantum electrodynamics, Pauli and Heisenberg were determined to derive it from quantum theory rather than introducing it from the start. They believed that if they could find a version of quantum electrodynamics capable of producing the fine structure constant, it would not contain the infinities that marred their theories.”
― Arthur I. Miller, Deciphering the Cosmic Number: The Strange Friendship of Wolfgang Pauli and Carl Jung