Synchronicity is a concept developed by psychologist Carl Jung to describe a perceived meaningful coincidence. Jung described synchronicity as an "acausal connecting principle" in which events, both large and small, in the external world might align to the experience of the individual, perhaps mirroring or echoing personal concerns or thoughts. For example, while one of Jung's analysands described a dream about a scarab, a scarab-like beetle flew into the room. Because the scarab is an Egyptian symbol of rebirth, Jung felt that the coincidence was meant to underline the woman's need to escape an over-attachment to rationalism. Most people experience surprising coincidences from time to time. For example, you might encounter a reference to some obscure event in history for the first time and then see several unrelated references to the same event soon afterwards.
In his most famous description of synchronicity, Jung told a story about a man named Monsieur Deschamps and plum pudding. Deschamps' neighbor, Monsieur de Fontgibu, gave him plum pudding. In Paris ten years later, Deschamps orders plum pudding in a restaurant but discovers that the last serving was sold to de Fontgibu, who is unexpectedly in town and at that same restaurant. Years later, Deschamps is once again offered plum pudding at a social gathering. As Deschamps tells the gathering about the earlier coincidences, he is shocked to see de Fontgibu come in the door.
Although some scientists see potential evidence of synchronicity in areas of research such as quantum theory , chaos theory , and fractal geometry, the concept is not testable by any current scientific method. Skeptics, such as Robert Todd Carroll of the Skeptic's Dictionary, argue that the perception of synchronicity is better explained as apophenia , which is the human tendency to seek and perceive connections between unrelated phenomena.
The concept of synchronicity is somewhat related to the concept of serendipity .