Synchronicity, in full
Jung used the word publicly for the first time in 1930, in a memorial address for the sinologist Richard Wilhelm, where he said the science of the I Ching rests on a principle other than causality. He worked on it for the next two decades and published the mature statement in 1952, in a volume he brought out jointly with the physicist Wolfgang Pauli. The long correspondence between the two men shaped the idea on both sides.
What Jung meant was narrower than coincidence in general. The pairing had to be acausal, and it had to carry meaning for the person living through it, usually meaning that tied an inner state to an outer event. His stock illustration was a patient recounting a dream about a golden scarab while a rose chafer beetle tapped at the consulting-room window. He took such pairings as evidence for an ordering principle in nature sitting alongside cause and effect.
That last claim is where synchronicity sits outside science. It is not testable in the way a claim about causation is, and ordinary probability already accounts for striking coincidences arriving at a steady rate across a large population of events. The term stays useful as a description of how a coincidence feels from the inside. It is not evidence that anything arranged it.
- Pattern-seeing
- Meaningful coincidence
A worked example
In a room of 23 people the chance that at least two share a birthday is about 50.7%, and with 70 people it climbs past 99.9%. The pair who match will often experience the match as pointed, especially if they have just been talking. Nothing arranged it. Coincidences of that shape are not rare events at all, they are the ordinary output of a large number of chances.
Sources
Jung used the term in a 1930 lecture discussing the I Ching, and his mature statement of synchronicity was first published in 1952, following a long correspondence with the physicist Wolfgang Pauli.
Princeton University Press — C. G. Jung, Synchronicity: An Acausal Connecting Principle
See also
Where it comes up on this site
Synchronicity: frequently asked
He coined this sense of it. The English word already existed for simultaneity in general; the meaningful-coincidence reading is his, used publicly from 1930 and set out at length in 1952.
No. It belongs to analytical psychology, and it is not framed in a way that could be tested. Standard probability already accounts for surprising coincidences without an extra principle.
The frequency illusion is a documented effect with a known mechanism: you become alert to something, then start noticing it and counting the hits. Synchronicity is not a mechanism at all but an interpretation laid over a coincidence, proposing that the pairing means something. One explains why you noticed. The other says the noticing was pointed at you, which is the part with nothing behind it.