The concept of synchronicity
The idea of synchronicity is that the conceptual relationship of minds, defined by the relationship between ideas, is intricately structured in its own logical way and gives rise to relationships which have nothing to do with causal relationships in which a cause precedes an effect. 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 Jung.
Carl Gustav Jung coined the word to describe what he called “temporally coincident occurrences of acausal events.”
Jung variously described synchronicity as an “‘acausal connecting principle'” (i.e., a pattern of connection that cannot be explained by conventional, efficient causality), “meaningful coincidence” and “acausal parallelism”. Jung introduced the concept in his 1952 paper “Synchronicity — An Acausal Connecting Principle”, though he had been considering the concept for almost thirty years.
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 underlay the whole of human experience and history — social, emotional, psychological, and spiritual.
Jung believed that many experiences perceived as coincidence were not merely due to chance but, instead, suggested the manifestation of parallel events or circumstances reflecting this governing dynamic. 
One of Jung’s favorite quotes on synchronicity was from Through the Looking-Glass by Lewis Carroll, in which the White Queen says to Alice:
“It’s a poor sort of memory that only works backwards”. 
Events that happen which appear at first to be coincidence but are later found to be causally related are termed Incoincident.
A well-known example of synchronicity is the true story of the French writer Émile Deschamps who in 1805 was treated to some plum pudding by the stranger Monsieur de Fortgibu. Ten years later, he encountered plum pudding on the menu of a Paris restaurant, and wanted to order some, but the waiter told him the last dish had already been served to another customer, who turned out to be de Fortgibu.
Many years later, in 1832, Émile Deschamps was at a diner, and was once again offered plum pudding. He recalled the earlier incident and told his friends that only de Fortgibu was missing to make the setting complete — and in the same instant the now senile de Fortgibu entered the room.
A mother is working at preparing her dinner, and thinks “It would be nice to have some flowers here today,” while her son is in the garden picking flowers for her dinner. The mother has never had flowers on the dinner table before, and the son has never brought flowers, but their close relationship leads them to both originally create the same idea at the same time.
Simultaneous discovery, the creation of the same new idea at causally disconnected places by two persons at approximately the same time. It is very difficult to account for simultaneous discovery by random chance. 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 is an example of synchronicity. This is explained by reasons such as global culture, which is the larger framework required to fit the definition of synchronicity.
During 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. 
The Wizard of Oz and Pink Floyd are part of the alleged Dark Side of the Rainbow synchronicity.
A recent study within the Princeton Engineering Anomalies Research Lab (the PEAR lab), suggested that there is a small, though statistically measurable, link between human thought and patterns that occur in random data sets.
There is no evidence as to whether this is caused by individuals unintentionally recognizing complex patterns and then molding their thoughts towards an unconsciously known result or the thoughts of the individual are themselves affecting the random patterns in a manner of individuation. This study’s results have not been replicated, and its methodologies are disputed.
The PEAR lab closed at the end of February, 2007, after conducting 28 years of research on the relationships and interactions between Mind and Matter.
According to Occam’s razor, positing an underlying mechanism for meaningfully interpreted correlations is an unsupported explanation for a “meaningful coincidence” which may be explained by simple coincidence.
Jung and followers believe that Synchronous events such as simultaneous discovery happen far more often than random chance would allow, even after accounting for the sampling bias inherent in the fact that meaningful coincidences are noticeable while meaningless coincidences are not.
References in popular culture
John Constantine, the main character in the Vertigo Comics series Hellblazer, is sometimes seen “riding the synchronicity highway,” to meet certain goals or even just to one up those around him. This has the same effect as that described in this article, and it is one of John Constantine’s more unusual tricks, and part of what makes him so dangerous. He is also seen doing this in Books of Magic, the graphic novel by Neil Gaiman.
The phenomenon is also explored, though not named, in “The Red Notebook” by Paul Auster, and is considered a major theme of his entire bibliography, appearing in some form in almost every work.
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 latter song contrasts the dangerous breakdown of a desperate family man with the simultaneous emergence of a menacing something from the bottom of a dark Scottish loch. See The Police, Robert Aziz and marketing the A&M album, Synchronicity.
In the 1976 film The Eagle Has Landed, the character Max Radl (Robert Duvall) asks a subordinate if he is familiar with the works of Jung, and then explains the theory of Synchronicity.
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 (see A suffusion of yellow).
The concept of ta’veren in Robert Jordan’s The Wheel of Time series functions similarly to synchronicity.
In the film Repo Man Miller’s famous Plate ‘o’ Shrimp theory is an exact representation of synchronicity.
In a 2002 album Tenth Dimensions by metal artist Blaze, a lot of the songs refer to synchronicity, with some songs like “Stealing Time” directly using the word.
In the film I ♥ Huckabees, a character hires existential detectives to solve his coincidence. They caution him: “Not all coincidences are meaningful!”
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 accurately predict certain possible futures.
In the D20 Modern roleplaying game Urban Arcana, Synchronicity is a magic spell that subtly rearranges reality, allowing the subject to avoid the minor inconveniences and hassles of everyday life. While the spell is in effect, buses and trains run on time, stoplights and crosswalk signals change in your favor just as you approach an intersection, and the flow of street traffic and pedestrians will allow you to proceed unimpeded, without hurry or delay. Waiters and clerks will approach as soon as they are wanted, and depart when you desire privacy. Taxi cabs, elevators, vacant parking spaces, and so forth will similarly be available wherever and whenever needed. This spell is particularly helpful when the subject is chasing someone or is trying to escape pursuers.
In the television series Strange Luck, the main character Chance Harper spends his entire life experiencing unplanned synchronicity, which he takes advantage of by becoming a freelance photographer.
The Dalai Lama quoted: “I am open to the guidance of synchronicity, and do not let expectations hinder my path.”
Terence McKenna used the term ‘Cosmic giggle’ to mean “a randomly roving zone of synchronicity and statistical anomaly. Should you be caught up in it, it will turn reality on its head. It is objective and subjective, simultaneously ‘really there’ and yet somehow is sustained by imagination and expectation….” 
Roderick Main (2000). Religion, Science, and Synchronicity. Harvest: Journal for Jungian Studies.
Jung defined the collective unconscious as akin to instincts in Archetypes and the Collective Unconscious.
In Synchronicity in the final two pages of the Conclusion, Jung stated that not all coincidences are meaningful and further explained the creative causes of this phenomenon.
Through the Looking-Glass, by Lewis Carroll, Ch. 5, Wool and Water.
‘It’s very good jam,’ said the Queen.
‘Well, I don’t want any TO-DAY, at any rate.’
‘You couldn’t have it if you DID want it,’ the Queen said. ‘The rule is, jam to-morrow and jam yesterday–but never jam to-day.’
‘It MUST come sometimes to “jam to-day,”‘ Alice objected.
‘No, it can’t,’ said the Queen. ‘It’s jam every OTHER day: to-day isn’t any OTHER day, you know.’
‘I don’t understand you,’ said Alice. ‘It’s dreadfully confusing!’
‘That’s the effect of living backwards,’ the Queen said kindly: ‘it always makes one a little giddy at first–‘
‘Living backwards!’ Alice repeated in great astonishment. ‘I never heard of such a thing!’
‘–but there’s one great advantage in it, that one’s memory works both ways.’
‘I’m sure MINE only works one way,’ Alice remarked. ‘I can’t remember things before they happen.’
‘It’s a poor sort of memory that only works backwards,’ the Queen remarked.
Jung, C. G., Synchronicity: An Acausal Connecting Principle, from The Collected Works of C. G. Jung, vol. 8, page 15, Princeton/Bollingen, 1973
From the wikiquote page on Repo Man:
A lot o’ people don’t realize what’s really going on. They view life as a bunch o’ unconnected incidents ‘n things. They don’t realize that there’s this, like, lattice o’ coincidence that lays on top o’ everything. Give you an example; show you what I mean: suppose you’re thinkin’ about a plate o’ shrimp. Suddenly someone’ll say, like, plate, or shrimp, or plate o’ shrimp out of the blue, no explanation. No point in lookin’ for one, either. It’s all part of a cosmic unconsciousness.
References and further reading
Carl Jung (1972). Synchronicity — An Acausal Connecting Principle. Routledge and Kegan Paul. ISBN 0-7100-7397-6.
Carl Jung (1977). Jung on Synchronicity and the Paranormal: Key Readings. Routledge. ISBN 0-415-15508-8.
Carl Jung (1981). The Archetypes and the Collective Unconscious. Princeton University Press. ISBN 0-691-01833-2.
Robert Aziz, C.G. Jung’s Psychology of Religion and Synchronicity (1990), currently in its 10th printing, is a refereed publication of The State University of New York Press. ISBN 0-7914-0166-9.
Robert Aziz, Synchronicity and the Transformation of the Ethical in Jungian Psychology in Carl B. Becker, ed. Asian and Jungian Views of Ethics. Westport, CT: Greenwood, 1999. ISBN 0-313-30452-1.
Robert Aziz, The Syndetic Paradigm: The Untrodden Path Beyond Freud and Jung (2007), a refereed publication of The State University of New York Press ISBN 13:978-0-7914-6982-8.
Marie-Louise von Franz (1980). On Divination and Synchronicity: The Psychology of Meaningful Chance. Inner City Books. ISBN 0-919123-02-3.
Joseph Jaworski (1996). Synchronicity: the inner path of leadership. Berrett-Koehler Publishers Inc.. ISBN 1-881052-94-X.
Arthur Koestler (1973). The Roots of Coincidence. Vintage. ISBN 0-394-71934-4.
Victor Mansfield, (Physicist) (1995). Science, Synchronicity and Soul-Making. Open Court Publishing Company. ISBN 0-8126-9304-3.
Elisabeth Mardorf, Das kann doch kein Zufall sein 
F. David Peat (1987). Synchronicity, The Bridge Between Matter and Mind. Bantam. ISBN 0-553-34676-8.
Richard Wilhelm (1986). Lectures on the I Ching: Constancy and Change Bollingen edition. Princeton University Press; Reprint. ISBN 0-691-01872-3. Note especially the foreword by Carl Jung. (The I Ching is a type of oracle, or ‘synchronicity computer’, used for divination.)
This article was originally posted on Biblioteca Pleyades