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.

Through Jung [Pauli] became very interested in various kinds of mysticism, including Jewish mysticism. This led Pauli to develop a friendship with Gershom Scholem, the world's greatest authority in that field and in the Cabala, .... On one occasion Scholem asked me to tell him about unsolved problems in modern physics. .... When I mentioned this number --137-- to Scholem, .... He told me that in Hebrew .... The number corresponding to the word 'cabala' happens to be 137.