View source for Coincidence

{{Short description|Concurrence of events with no connection}}
{{redirect|Coincide|the album by Dewey Redman|Coincide (album)}}
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[[File:Total solar eclipse 2017 at Orin Junction, Wyoming - 03.jpg|alt=An image of a total solar eclipse at Orin Junction, Wyoming in 2017. A total solar eclipse happens when the Moon completely blocks the face of the Sun.  It is the result of a cosmic coincidence. Even though the Sun is about 400 times bigger than the Moon, it is also about 400 times farther away. This makes the Sun and the Moon appear almost exactly the same size in our sky. |thumb|[[Solar eclipse of August 21, 2017|A total solar eclipse at Orin Junction, Wyoming in 2017]]. A [[Solar eclipse|total solar eclipse]] happens when the [[Moon]] completely blocks the face of the [[Sun]]. It is the result of a cosmic coincidence: Even though the Sun is about 400 times bigger than the Moon, it is also about 400 times farther away. This makes the Sun and the Moon appear almost exactly the same size in Earth's sky.<ref>{{Cite web |title=Why Do Eclipses Happen? - NASA Science |url=https://science.nasa.gov/eclipses/geometry/ |access-date=2023-11-12 |website=science.nasa.gov |date=14 October 2022 |language=en}}</ref>]]
A '''coincidence''' is a remarkable concurrence of events or circumstances that have no apparent causal connection with one another.<ref name="Stevenson">{{Cite book|last=Stevenson|first=Angus|title=Oxford Dictionary of English|date=2010|publisher=OUP Oxford|isbn=978-0-19-957112-3 |page=339 |url=https://books.google.com/books?id=anecAQAAQBAJ&pg=PA339}}</ref> The perception of remarkable coincidences may lead to [[supernatural]], [[occult]], or [[paranormal]] claims, or it may lead to belief in [[fatalism]], which is a doctrine that events will happen in the exact manner of a predetermined plan. In general, the perception of coincidence, for lack of more sophisticated explanations, can serve as a link to [[folk psychology]] and philosophy.<ref name=experience/>

From a [[Statistics|statistical]] perspective, coincidences are inevitable and often less remarkable than they may appear intuitively. Usually, coincidences are [[event (probability)|chance events]] with underestimated [[probability]].<ref name=experience>{{Cite book |doi=10.1007/978-3-319-26300-7_9 |chapter=The Experience of Coincidence: An Integrated Psychological and Neurocognitive Perspective |title=The Challenge of Chance |series=The Frontiers Collection |date=2016 |last1=Van Elk |first1=Michiel  |last2=Friston |first2=Karl |author-link2=Karl Friston |last3=Bekkering |first3=Harold |author-link3=Harold Bekkering |pages=171–185 |isbn=978-3-319-26298-7|s2cid=3642342 }}</ref> An example is the [[birthday problem]], which shows that the [[probability]] of two persons having the same birthday already exceeds 50% in  a group of only 23 persons.<ref>{{cite journal |last=Mathis |first=Frank H. |date=June 1991 |title=A Generalized Birthday Problem |journal=SIAM Review |volume=33 |issue=2 |pages=265–70 |issn=0036-1445 |doi= 10.1137/1033051 |oclc=37699182 |jstor=2031144 }}</ref> Generalizations of the birthday problem are a key tool used for mathematically modelling coincidences.<ref name="Pollanen">M. Pollanen (2024) ''A Double Birthday Paradox in the Study of Coincidences'', [[Mathematics]] '''23'''(24), 3882. https://doi.org/10.3390/math12243882</ref>

==Etymology==
The first known usage of the word coincidence is from c. 1605 with the meaning "exact correspondence in substance or nature" from the French ''coincidence'', from ''coincider'', from Medieval Latin ''coincidere''. The definition evolved in the 1640s as "occurrence or existence during the same time". The word was introduced to English readers in the 1650s by Sir [[Thomas Browne]],  in ''A Letter to a Friend'' (circa 1656 pub. 1690)<ref> that the first day should make the last, that the Tail of the Snake should return into its Mouth precisely at that time, and they should wind up upon the day of their Nativity, is indeed a remarkable Coincidence, which tho Astrology hath taken witty pains to salve, yet hath it been very wary in making Predictions of it ( A Letter to a Friend)</ref> and in his discourse ''[[The Garden of Cyrus]]'' (1658).<ref>' Now although this elegant ordination of vegetables, hath found coincidence or imitation in sundry works of Art'(opening of the third chapter of 'The Garden of Cyrus') </ref>

==Synchronicity==
{{main|Synchronicity}}
Swiss psychiatrist [[Carl Jung]] developed a theory that states that remarkable coincidences occur because of what he called "[[synchronicity]]," which he defined as an "acausal connecting principle."<ref>{{cite book |last=Jung |first=Carl |author-link=Carl Jung |edition=first Princeton/Bollingen paperback|date=1973 |title=Synchronicity: An Acausal Connecting Principle |url=https://archive.org/details/synchronicityaca00cgju |url-access=registration |location=Princeton, New Jersey |publisher=Princeton University Press |isbn=978-0-691-15050-5 }}</ref>

{{Quotation|The [[Carl Jung|Jung-]][[Wolfgang Pauli|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.|Arthur Koestler, ''[[The Roots of Coincidence]]''<ref>{{cite book |last=Koestler |first=Arthur |author-link=Arthur Koestler |title=The Roots of Coincidence |url=https://archive.org/details/rootsofcoinciden00koesrich |url-access=registration |edition=hardcover |publisher=Random House |year=1972 |isbn=978-0-394-48038-1 |page=[https://archive.org/details/rootsofcoinciden00koesrich/page/81 81]}}</ref>}}

One of Kammerer's passions was collecting coincidences. He published a book titled ''Das Gesetz der Serie'' (''The Law of Series''), which has not been translated into English.  In this book, he recounted 100 or so anecdotes of coincidences that led him to formulate his theory of seriality.

He postulated that all events are connected by waves of seriality. Kammerer was known to make notes in public parks of how many people were passing by, how many of them carried umbrellas, etc. [[Albert Einstein]] called the idea of seriality "interesting and by no means absurd."<ref>{{cite web |url=https://www.psychologytoday.com/us/blog/connecting-coincidence/201703/seriality-vs-synchronicity-kammerer-vs-jung |title=Seriality vs Synchronicity: Kammerer vs. Jung |first=Bernard D. |last=Beitman |work=Connecting with Coincidence |publisher=[[Psychology Today]] |date=2017-03-25}}</ref> Carl Jung drew upon Kammerer's work in his book ''Synchronicity''.<ref>{{cite book |last=Koestler |first=Arthur |author-link=Arthur Koestler |title=The Roots of Coincidence |url=https://archive.org/details/rootsofcoinciden00koes/page/87 |url-access=registration |edition=hardcover |publisher=Random House |year=1972 |isbn=978-0-394-48038-1 |page=87]}}</ref>

A coincidence lacks an apparent causal connection. A coincidence may be synchronicity — the experience of events that are causally unrelated — and yet their occurrence together has meaning for the person who observes them. To be counted as synchronicity, the events should be unlikely to occur together by chance, but this is questioned because there is usually a chance, no matter how small and in vast numbers of opportunities such coincidences do happen by chance if it is only non-zero (see [[law of truly large numbers]]).

Some skeptics (e.g., [[Georges Charpak]] and [[Henri Broch]]) argue synchronicity is merely an instance of [[apophenia]].<ref>{{cite web |url=http://www.skepdic.com/jung.html |title=Synchronicity |work=The Skeptic's Dictionary |first=Robert Todd |last=Carroll |author-link=Robert Todd Carroll |date=2012}}</ref> They argue that probability and statistical theory (exemplified, e.g., in [[Littlewood's law]]) suffice to explain remarkable coincidences.<ref name=Charpak>{{cite book |last1=Charpak |first1=Georges |author-link1=Georges Charpak |title=Debunked!: ESP, telekinesis, and other pseudoscience |year=2004 |publisher=Johns Hopkins Univ. Press |location=Baltimore |isbn=978-0-8018-7867-1 |first2=Henri |last2=Broch |translator-first1=Bart K. |translator-last1=Holland |url-access=registration |url=https://archive.org/details/debunked00geor}}</ref><ref>[[David C. Lane|David Lane]] & Andrea Diem Lane, 2010, [http://www.integralworld.net/lane15.html Desultory Decussation: Where Littlewood’s Law of Miracles meets Jung’s Synchronicity], www.integralworld.net</ref>

[[Charles Fort]] also compiled hundreds of accounts of interesting coincidences and strange phenomena.

==Causality==
{{main|Causality}}
Measuring the [[probability]] of a series of coincidences is the most common method of distinguishing a coincidence from causally connected events.

{{Quotation|The mathematically naive person seems to have a more acute awareness than the specialist of the basic paradox of probability theory, over which philosophers have puzzled ever since Pascal initiated that branch of science [in 1654] .... The paradox consists, loosely speaking, of the fact that probability theory is able to predict with uncanny precision the overall outcome of processes made up of numerous individual happenings, each of which in itself is unpredictable. In other words, we observe many uncertainties producing certainty, and many chance events creating a lawful total outcome.|Arthur Koestler, ''[[The Roots of Coincidence]]''<ref>{{cite book |last=Koestler |first=Arthur |author-link=Arthur Koestler |title=The Roots of Coincidence |url=https://archive.org/details/rootsofcoinciden00koes |url-access=registration |page=[https://archive.org/details/rootsofcoinciden00koes/page/25 25] |edition=hardcover |publisher=Random House |year=1972 |isbn=978-0-394-48038-1 |postscript= – 1973 Vintage paperback:}}</ref>}}

To establish cause and effect (i.e., [[causality]]) is notoriously difficult, as is expressed by the commonly heard statement that "[[correlation does not imply causation]]." In [[statistics]], it is generally accepted that observational studies can give hints but can never establish cause and effect. But, considering the probability paradox (see Koestler's quote above), it appears that the larger the set of coincidences, the more certainty increases, and the more it seems that there is some cause behind a remarkable coincidence.

{{Quotation| ... it is only the manipulation of uncertainty that interests us. We are not concerned with the matter that is uncertain. Thus we do not study the mechanism of rain; only whether it will rain.|[[Dennis Lindley]], "The Philosophy of Statistics," ''[[Journal of the Royal Statistical Society|The Statistician]]'' (Series D, 2000)}}

{{Quotation|It is no great wonder if in the long process of time, while [[Fortuna|fortune]] takes her course hither and thither, numerous coincidences should spontaneously occur.|[[Plutarch]], ''[[Parallel Lives]]'', vol. II, "Sertorius"}}

==See also==
{{cols|colwidth=26em}}
* [[Alignments of random points]]
* [[Bible code]]
*''[[Coincidance]]''
* [[Confirmation bias]]
* [[Ideas of reference and delusions of reference]]
* [[Ley line]]
* [[Mathematical coincidence]]
* [[Pareidolia]]
* [[Post hoc ergo propter hoc]]
* ''[[The Roots of Coincidence]]''
* [[Synchronicity (book)|''Synchronicity'' (book)]]
* [[Synchronism (disambiguation)|Synchronism]]
{{colend}}

==References==
{{Reflist}}

==Bibliography==
* [[David Marks (psychologist)|David Marks]]: ''[[The Psychology of the Psychic]]''. pp.&nbsp;227–46
* [[Joseph Mazur]] (2016). ''Fluke: The Maths and Myths of Coincidences'', London: Oneworld Publications. {{ISBN|978-1-78074-899-3}}

==Further reading==
*{{cite book|title=Meaningful Coincidences How and Why Synchronicity and Serendipity Happen|isbn=9781644115718|author=Bernard Beitman|date=6 September 2022 |publisher=Inner Traditions Bear}}
*{{cite book|title=Connecting with Coincidence The New Science for Using Synchronicity and Serendipity in Your Life|isbn=9780757318849|author=Bernard Beitman|date=7 March 2016 |publisher=Health Communications, Incorporated}}

==External links==
{{Wiktionary}}
{{Wikiquote|coincidence}}

* [https://web.archive.org/web/20120316202416/http://nephiliman.com/Paralells.htm Collection of  Historical Coincidence], nephiliman.com (web.archive.org)
* [http://www.icsahome.com/elibrary/studyguides/education/astopunlikelyeventsandcoincidence Unlikely Events and Coincidence], Austin Society to Oppose Pseudoscience
* [http://understandinguncertainty.org/node/129 Why coincidences happen], UnderstandingUncertainty.org
* [https://understandinguncertainty.org/coincidences/#coincidences The Cambridge Coincidences Collection], University of Cambridge Statslab
* [http://www.geoffkirby.co.uk/Fancy%20Meeting%20You%20Here!.pdf The mathematics of coincidental meetings]

[[Category:Coincidence| ]]
[[Category:Causality]]
[[Category:Concepts in metaphysics]]
[[Category:Philosophy of physics]]
[[Category:Philosophy of time]]
[[Category:Synchronicity]]
[[Category:Articles containing video clips]]