• The problem of synchronicity has puzzled me for a long time, ever since the middle twenties, when I was investigating the phenomena of the collective unconscious and kept on coming across connections which I simply could not explain as chance groupings or "runs." What I found were "coincidences" which were connected so meaningfully that their "chance" concurrence would represent a degree of improbability that would have to be expressed by an astronomical figure.

    Carl Gustav Jung (1981). “The Collected Works of C. G. Jung: Structure and dynamics of the psyche”