A coincidence lacks a definite causal connection. Any given set of coincidences may be just a form of synchronicity, that being the experience of events which are causally unrelated, and yet their occurring together carries meaning to the person observing the events. (In order to count as synchronicity, the events should be unlikely to occur together by chance.)
The Jung-Pauli theory of “synchronicity”, conceived by a physicist and a psychologist, both eminent in their fields, represents perhaps the most radical departure from the world-view of mechanistic science in our time. Yet they had a precursor, whose ideas had a considerable influence on Jung: the Austrian biologist Paul Kammerer, a wild genius who committed suicide in 1926, at the age of forty-five.
One of Kammerer’s passions was collecting coincidences. He published a book with the title Das Gesetz der Serie (The Law of the Series; never translated into English) in which he recounted 100 or so anecdotes of coincidences that had led him to formulate his theory of Seriality.
He postulated that all events are connected by waves of seriality. These unknown forces would cause what we would perceive as just the peaks, or groupings and coincidences. Kammerer was known to, for example, make notes in public parks of what numbers of people were passing by, how many carried umbrellas, etc. Albert Einstein called the idea of Seriality “Interesting, and by no means absurd”, while Carl Jung drew upon Kammerer’s work in his essay Synchronicity.
Science is the practice of constructing theoretical explanations of how events (phenomena) happen to repeatedly coincide. Remarkable coincidences sometimes lead to theories involving the supernatural or psychic forces. Or the explanation that a person or persons intentionally acted and the coincidence is the evidence these actions (aka conspiracy theories).
Some researchers (e.g. Charles Fort and Carl Jung) have compiled thousands of accounts of coincidences and other supposedly anomalous phenomena (synchronicity). The perception of coincidences often leads to occult or paranormal claims. It may also lead to the belief system of fatalism, that events will happen in the exact manner of a predetermined plan or formula. This lends a certain aura of inevitability to events.
In The Psychology of the Psychic, David Marks describes four distinct meanings of the term “coincidence”. Marks suggests that coincidences occur because of “odd matches” when two events A and B are perceived to contain a similarity of some kind. For example, dreaming of a plane crash (event A) would be matched by seeing a news report of a plane crash the next morning (event B).
Deepak Chopra and other proponents of ancient Vedic spiritual and other mystical teachings insist on the view that there is absolutely no coincidence in the world. Everything that occurs can be related to a prior cause or association, no matter how vast or how minute and trivial. All is affected by something related to it that is seen or unseen, cognized or unknowable.