The concept does not question, or compete with, the notion of causality. Instead, it maintains that just as events may be grouped by cause, they may also be grouped by their meaning.
In order to be synchronistic, the events must be related to one another temporally so as to rule out direct causation.
The idea of synchronicity is that the conceptual relationship of minds, defined as the relationship between ideas, is intricately structured in its own logical way and gives rise to relationships which are not causal in nature. Instead, causal relationships are understood as simultaneous—that is, the cause and effect occur at the same time.
Synchronous events reveal an underlying pattern, a conceptual framework which encompasses, but is larger than, any of the systems which display the synchronicity. The suggestion of a larger framework is essential in order to satisfy the definition of synchronicity as originally developed by Swiss psychologist Carl Gustav Jung.
Jung coined the word to describe what he called "temporally coincident occurrences of acausal events." Jung variously described synchronicity as an "acausal connecting principle", "meaningful coincidence" and "acausal parallelism". Jung introduced the concept as early as the 1920s but only gave a full statement of it in 1951 in an Eranos lecture and in 1952, published a paper, Synchronicity — An Acausal Connecting Principle, in a volume with a related study by the physicist (and Nobel laureate) Wolfgang Pauli.
It was a principle that Jung felt gave conclusive evidence for his concepts of archetypes and the collective unconscious, in that it was descriptive of a governing dynamic that underlies the whole of human experience and history—social, emotional, psychological, and spiritual. Events that happen which appear at first to be coincidence but are later found to be causally related are termed as "incoincident".
Jung believed that many experiences that are coincidences due to chance in terms of causality suggested the manifestation of parallel events or circumstances in terms of meaning, reflecting this governing dynamic.
In psychology and cognitive science, confirmation bias is the tendency to search for or interpret new information in a way that confirms one's preconceptions and avoids information and interpretations that contradict prior beliefs. Many critics believe that any evidence for synchronicity is due to confirmation bias, and nothing else.
Wolfgang Pauli, a scientist who in his professional life was severely critical of confirmation bias, lent his scientific credibility to support the theory, coauthoring a paper with Jung on the subject. Some of the evidence that Pauli cited was that ideas which occurred in his dreams would have synchronous analogs in later correspondence with distant collaborators.
In his book Synchronicity (1952), Jung tells the following story as an example of a synchronic event: "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 the 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 one finds in our latitudes, a scarabaeud beetle, the common rose-chafer (Cetonia aurata), which contrary to its usual habits had evidently felt the 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." (The Collected Works of C.G. Jung, paragraph 843, Princeton University Press Edition)
Simultaneous discovery is the creation of the same new idea at causally disconnected places by two persons at approximately the same time. If, for example, an American and a British musician, having never had anything to do with one another, arrived at the same musical concept, chord sequence, feel or lyrics at the same time in different places, this would be an example of synchronicity. During the production of The Wizard of Oz, a coat bought from a second-hand store for the costume of Professor Marvel was later found to have belonged to L. Frank Baum, author of the children's book upon which the film is based.
In the 2004 film I ♥ Huckabees, a character hires existential detectives to solve his coincidence. They caution him, "Not all coincidences are meaningful."
The 2007 film August Rush features a plot built upon several synchronicities, all surrounding a series of unlikely meetings and occurrences that ultimately lead to a reunion between the title character and his parents.
Writer and iconoclast Charles Hoy Fort wrote several books on synchronicity, including the Book of the Damned, Lo!, New Lands and Wild Talents. New Lands tells the famous story of the woman who lost her ring in a nearby lake only to recover it years later inside a fish she bought at a local market. He also wrote about the butterfly effect years before Lorenz, the famous mathematician who coined the term.
In the 1983 release Synchronicity by The Police (A&M Records), bassist Sting is reading a copy of Jung's Synchronicity on the front cover along with a negative/superimposed image of the actual text of the synchronicity hypothesis. A photo on the back cover also shows a close-up, but mirrored and upside-down, image of the book. There are two songs, titled "Synchronicity I" and "Synchronicity II" included in the album.
The Dirk Gently series of books by Douglas Adams often plays on the synchronicity concept. The main character carries a "pocket I Ching" that also functions as a calculator, up to a point. In Philip K. Dick's The Game-Players of Titan, several characters possessing pre-cognitive abilities cite the acausal principle of synchronicity as an element which hampers their ability to predict certain possible futures accurately.
In 2002, manga author Itagaki Keisuke based one of the story arcs of Baki The Search Of Our Strongest Hero on the synchronicity theme, presenting a story in which five death row inmates escaped at the same time, in different countries, each after surviving his own execution. Each inmate went back to Japan at the same time to meet in the same place for the same objective.