SYNCHRONICITY: AN ACAUSAL CONNECTING PRINCIPLE by Carl Gustav Jung

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. By way of example,
I shall mention an incident from my own observation. A young woman I
was treating had, at a critical moment, a dream in which she was given a
golden scarab. While she was telling me this dream I sat with my back to
the closed window. Suddenly I heard a noise behind me, like a gentle
tapping. I turned round and saw a flying insect knocking against the
window-pane from outside. I opened the window and caught the creature
in the air as it flew in. It was the nearest analogy to a golden scarab that
one finds in our latitudes, a scarabaeid beetle, the common rose-chafer
(Cetonia aurata), which contrary to its usual habits had evidently felt an
urge to get into a dark room at this particular moment. I must admit that
nothing like it ever happened to me before or since, and that the dream of
the patient has remained unique in my experience.