The Exclusion Principle

An excerpt from Pauli and Jung: The Meeting of Two Great Minds

The exclusion principle was certainly not a swindle. Of far-reaching consequence, it accounts for the periodic system of elements, as found in the periodic table. By analyzing the atomic line spectra of the various elements, Pauli was able to arrive at the principle that accounts for the unique shell structure of the electrons surrounding the atomic nucleus of each of the chemical elements. A key to this scientific achievement was his recognition that the electrons must satisfy four quantum numbers rather than three, as had previously assumed. The fourth quantum number was identified with what has been called an electron spin.
In alchemy as well as in Jung's psychology, moving from three to four symbolizes a completion, or a movement toward the center. In association with modern dreams, Jung saw movement from three to four as symbolizing a stage of inner development known as the individuation process. Pauli saw his discovery of the exclusion principle in that light. Pauli's exclusion principle confirmed Bohr's proposed shell structure of the atom.