Microphysics is feeling its way into the unknown side of matter, just as complex psychology is pushing forward into the unknown side of the psyche. Both lines of investigation have yielded findings which can be conceived only by means of antinomies, and both have developed concepts which display remarkable analogies. If this trend should become more pronounced in the future, the hypothesis of the unity of their subject-matters would gain in probability. The common background of microphysics and depth-psychology is as much physical as psychic and therefore neither, but rather a third thing, a neutral nature which can at most be grasped in hints since in essence it is transcendental.

C.G. Jung, Mysterium Conjunctionis