Coincidence and synchronicity: what is the difference?

Synchronicity according to Jung

Carl Gustav Jung coined the notion of synchronicity in a 1952 essay, published with the physicist Wolfgang Pauli (Naturerklärung und Psyche). It designates a coincidence that makes sense to the person, with no causal link between the two events. What matters is therefore not chance itself, but the meaning one finds in it.

Collecting series

Before Jung, the biologist Paul Kammerer collected series of coincidences, which he gathered in Das Gesetz der Serie (1919). This passion shows how old the attention to repetitions is. It does not say that a secret law governs them, but that they intrigued very rigorous minds, long before anyone spoke of signs or synchronicities.

Littlewood’s law

The mathematician J. E. Littlewood observed (A Mathematician’s Miscellany, 1953) that at a rate of one event noticed per second, each of us lives through about one “miracle” with a one-in-a-million chance per month. Freeman Dyson named it that in 2004. In other words, rare coincidences become almost inevitable when you look for long enough, and it is not surprising that a striking series eventually happens in a life.

Keeping what touches you

Knowing that a coincidence is statistically expected takes nothing away from what it sets resonating in you. You can take it for what it is: a moment when something of your thoughts meets something of your day. Noting these moments helps you see which ones return, and what they answer to.

Facts and sources

• Jung coined the notion of synchronicity (a 1952 essay, published with Wolfgang Pauli): a coincidence that is meaningful to the person, with no causal link. C. G. Jung and W. Pauli, Naturerklärung und Psyche, 1952 (checked for the plan on October 12, 2026)
• The biologist Paul Kammerer collected series of coincidences (Das Gesetz der Serie, 1919). Paul Kammerer, Das Gesetz der Serie, 1919; P. Diaconis and F. Mosteller, “Methods for Studying Coincidences,” Journal of the American Statistical Association, 1989
• “Littlewood’s law”: at the rate of one noticed event per second, everyone experiences about one one-in-a-million “miracle” per month. The idea comes from the mathematician J. E. Littlewood (A Mathematician’s Miscellany, 1953); Freeman Dyson gave it this name in 2004. J. E. Littlewood, A Mathematician’s Miscellany, 1953; Freeman Dyson, The New York Review of Books, 2004; Wikipedia (en), “Littlewood’s law”