What is synchronicity?
Synchronicity is the term the Swiss psychiatrist Carl Jung gave to a meaningful coincidence: two events that have no causal connection, yet fall together in a way that carries unmistakable meaning for the person who experiences them. Jung’s insight was that, just as events can be linked by cause and effect, they can also be linked by meaning. He called synchronicity an “acausal connecting principle”, a form of order in experience that ordinary cause-and-effect thinking cannot account for.
What synchronicity means, in Jung’s own words
The word is Jung’s own construction, from the Greek syn, together, and chronos, time: a falling-together in time.
He used it publicly for the first time in 1930, in a memorial address for the sinologist Richard Wilhelm, and spent the next two decades refining it. The full statement came in 1952, in the essay Synchronicity: An Acausal Connecting Principle.
That phrase is the definition, and each word in it is doing work.
Acausal means the two events do not cause one another. Neither the thought nor the outer event produced the other, and looking for a mechanism between them is looking for something that is not there.
Connecting means they are nevertheless related. Jung was not describing coincidence dressed up; he was proposing that meaning can order events in the way that causality does.
Principle means he intended it as a category of explanation standing alongside cause and effect, not beneath it. That is the claim that made physicists interested and made many psychologists uncomfortable, and it is still the point on which the argument turns.
Meaning, not just coincidence
The distinction matters, because not every coincidence is a synchronicity. If a passenger sneezes just before a plane makes an emergency landing, that is mere chance, two unrelated events happening close together. But if you think of an old friend you have not seen in years, and that afternoon they call, at a moment when their return means something to you, the coincidence is charged with meaning. What makes an event synchronistic is not its improbability alone, but that the outer event mirrors an inner state, and that the correspondence feels significant rather than random.
Jung’s scarab beetle: the classic example
Jung set out the idea most fully in his 1952 essay, Synchronicity: An Acausal Connecting Principle, developed in dialogue with the physicist Wolfgang Pauli. He illustrated it with a case from his own consulting room. He was treating a woman whose rigid rationalism made the work impossible to move. One day she recounted a dream in which she was given a golden scarab, a symbol of rebirth. As she spoke, Jung heard a tapping at the window: a rose-chafer beetle, the closest local equivalent to a scarab, was trying to get in. He caught it and handed it to her with the words, “Here is your scarab.” The coincidence broke through her rationalism where argument had failed, and the treatment finally began to move.
Examples of synchronicity
The scarab is the famous one because Jung wrote it down. The ones that bring people into consultation are quieter.
A name, then the name. You think of someone you have not seen in fifteen years, without prompting, and they write that evening. What makes it synchronistic is not the improbability but the timing: it happens in the week you were deciding whether to leave a marriage that began around the time you knew them.
The book that falls open. A sentence answers a question you have not spoken aloud. Jung would not have called the book prophetic. He would have asked what in you was ready to receive that sentence, and why now.
The recurring image. A bird, a number, a piece of music appears repeatedly over a period of days that also happens to contain a death, a diagnosis, or a decision.
The dream that arrives before the news. The most common one people describe in analysis, and the one they are most reluctant to mention in case it sounds foolish.
In each case the structure is identical: an inner state and an outer event correspond, the correspondence carries meaning for that person, and no causal path connects them.
Jung and the physicist: Wolfgang Pauli
Synchronicity did not develop in a consulting room alone, and this is the part usually left out.
Wolfgang Pauli was one of the founders of quantum mechanics and won the Nobel Prize in Physics in 1945. He came to Jung’s circle in the early 1930s in considerable personal difficulty, and what began as treatment became a correspondence that lasted more than twenty years.
Pauli was interested in whether the categories physics had arrived at, complementarity, indeterminacy, the role of the observer, had any relation to what Jung was finding in the psyche. Jung was interested in whether meaning could be a principle of order in the way that energy is.
The 1952 essay was published in a joint volume with an essay by Pauli on the archetypal ideas in Kepler’s astronomy. That is the actual provenance of the concept: a psychiatrist and a Nobel physicist, each dissatisfied with what their own discipline could account for.
It is worth knowing because it separates Jung’s proposal from the use the word has since been put to. He was not offering reassurance. He was making a difficult argument, with a physicist, and he knew how difficult it was.
Synchronicity and the unconscious
For Jung, synchronicity was not a party trick of the universe but a window onto the deeper structure of the psyche. He connected it to the archetypes and the collective unconscious: at moments of psychological significance, when an archetype is activated, inner and outer can seem to arrange themselves around the same meaning. Synchronistic events cluster around exactly the times of upheaval, loss, love and transformation when the unconscious is most active. This is also why they so often accompany dreams and the process of individuation, the movement toward a more integrated Self.
Repeated numbers, 11:11, and what a Jungian would actually say
A great deal of what is now written about synchronicity concerns repeated numbers: seeing 11:11, or 333, and being told this is the universe confirming that you are on the right path.
A Jungian view of this is neither the dismissal nor the endorsement people expect.
The dismissal is easy and mostly correct. Once a number is salient you notice it, and stop noticing the hundreds of times you looked at a clock and it said something else. This is a well-described feature of attention, and it accounts for the large majority of these experiences.
But the interesting question is the other one. Why did that number become salient for you, in this month rather than any other? Something in you selected it. Jung’s interest was never in whether the universe was signalling; it was in what the psyche was doing, and a mind that has begun marking time with a particular number is a mind that is preoccupied with something.
So the analytic response is not “yes, it is a sign” and not “no, it is nothing”. It is: what is happening in your life at the moment, that this has started?
That question is usually more productive than either of the answers on offer elsewhere.
A necessary caution
Jung was careful, and it is worth being careful too. He repeatedly acknowledged that much of what looks improbable is simply improbable, without purpose or meaning. The human mind is a pattern-seeking instrument, and it will find significance where there is none. Synchronicity is not a licence to read messages into every coincidence, nor a substitute for judgement. It becomes worth attending to when the correspondences accumulate, when they touch something already alive in the person, and when the meaning is felt rather than manufactured.
Is synchronicity real? The objection, taken seriously
The scientific objection is straightforward and deserves a straight answer.
Human beings are pattern-detecting animals, and the detection runs whether or not there is a pattern. We remember the coincidence and forget the thousands of non-coincidences. We revise our memory of what we were thinking beforehand so that it fits what happened afterwards. And any sufficiently large number of events will contain improbable-looking clusters by chance alone. All of that is true, well evidenced, and accounts for most reported synchronicity.
Jung knew it, and said so repeatedly. He was insistent that most improbable things are simply improbable.
Where his idea is genuinely vulnerable is that acausal connection is difficult to test. Something that occurs unpredictably, cannot be produced on demand, and depends on the significance felt by the person experiencing it is not going to yield to a controlled trial, and it has not.
Which leaves a more modest but defensible position, and it is the one taken in this practice. Whether meaning organises events in the world is not something psychotherapy can settle. What is observable, and what matters clinically, is that these experiences arrive at particular moments in a life, cluster around upheaval and transition, and are almost always about something the person is not yet able to say directly. That is worth attending to regardless of what is happening in the universe.
Making sense of your own experiences
Many people have a synchronistic experience and do not know what to do with it: it feels important, but the rational mind dismisses it, and there is no one to help them think about it seriously. This is precisely the kind of material that Jungian analysis takes seriously, not as prophecy, but as a communication from the unconscious worth understanding. Working with a Jungian analyst offers a space to explore what such moments are pointing to in your own life, without either inflating them or explaining them away. The Jungian Confrerie is the practice of Dr Philippe Jacquet, offering Jungian analysis in central London and online worldwide.