Coincidence literally describes two or more events or entities occupying the same point in space or time, but colloquially means two or more events or entities possessing unexpected parallels, such as thinking about someone and then receiving an unexpected phone call from that person, when it is clear that there is no ordinary causal connection. An event is something that takes place; an occurrence and arbitrary point in time. ... Space is Big. ... // Time can be found in all corners of Earth Watches are used to measure time Trying to understand time has long been a prime occupation for philosophers, scientists and artists. ... A causal system is a system that depends only on the current and previous inputs. ...

The index of coincidence can be used to analyze whether two events are related. A coincidence does not prove a relationship, but related events may be expected to have a higher index of coincidence. From a statistical perspective, coincidences are inevitable and often less remarkable than they may appear intuitively. The odds that two people share a birthday, for example, reaches 50% with a group of just 22 [1]—about the number of a mid-sized social get-together. (See the Birthday paradox.) In cryptography, coincidence counting is the technique (invented by William F. Friedman) of putting two texts side-by-side and counting the number of times that a letter appears next to itself in both copies. ... The birthday paradox states that if there are 23 or more people in a room then there is a chance of more than 50% that at least two of them will have the same birthday. ...

Remarkable coincidences sometimes lead to claims of psychic phenomena or conspiracy theories. Some researchers (see Charles Fort and Carl Jung) have compiled thousands of accounts of coincidences and other anomalous phenomena. Parapsychology is the study of the evidence involving phenomena where a person seems to affect or gain information about something through a means not currently explainable within the framework of mainstream, conventional science. ... This proposed logo for the Information Awareness Office (a US governmental agency) was dropped due to fears that its pseudo-Masonic symbolism would provoke conspiracy theories. ... Charles Fort, 1920 Charles Hoy Fort (August 6, 1874 - May 3, 1932) was an American writer and researcher into anomalous phenomena. ... Carl Gustav Jung (July 26, 1875 – June 6, 1961) (IPA:) was a Swiss psychiatrist and founder of Analytical Psychology. ... Anomalous phenomena are phenomena which are observed and for which there are no suitable explanations in the context of a specific body of scientific knowledge, e. ...

In optics, coincidence is also used to refer to two or more incident beams of light that strike the same point at the same time. See also: List of optical topics Optics (appearance or look in ancient Greek) is a branch of physics that describes the behavior and properties of light and the interaction of light with matter. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength. ...

Types of Coincidences

The phenomenon we loosely term "coincidence" comprises many classes of events, including:

• The happy (long-lost lovers rediscover each other by accident)
• The amusing (a potato grows in a shape resembling Richard Nixon's profile)
• The mundane (neighbors share the same birthday)
• The fortunate (a hunch bet on a roulette wheel pays off)
• The eerie (a man is hit and killed by a car he'd sold ten years earlier)
• The life-saving (a last-minute change in travel plans heads off disaster)
• The tragic (sisters are killed when their vehicles collide as they travel to visit each other)

Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th President of the United States, serving from 1969 to 1974. ... A birthday is the date on which a person was born. ... Roulette is a casino and gambling game (Roulette is a French word meaning small wheel). A croupier turns a round roulette wheel which has 37 or 38 separately numbered pockets in which a ball must land. ...

Examples

• The Sun is 400 hundred times the diameter of the Moon and nearly 400 hundred times farther from the Earth. Thus the two bodies have almost exactly the same angular size when viewed from the earth; this gives rise to the characteristic appearance of solar eclipses, when the moon 'fits' exactly over the sun's disc.
• Hernán Cortés' arrival in Mexico in 1519 coincided with the year in the Mayan Calendar when it was predicted that the pale-faced man-god Quetzalcoatl would return to reclaim the city of Tenochtitlán. The Aztecs therefore assumed Cortés to be the legendary man-god, which assisted him in capturing the city and thence Mexico.
• In 1878 Leo XIII was elected, eventually becoming the third longest serving Pope. In 1978 John Paul II was elected, eventually became the third longest serving Pope.
• John Adams and Thomas Jefferson, two of America's Founding Fathers, died on July 4, 1826. It was exactly fifty years to the day since the country's inception.
• A well-known (though disputed) set of coincidences involves the assassinations of Abraham Lincoln and John F. Kennedy. See Lincoln-Kennedy coincidences.

For other uses, see Sun (disambiguation). ... Crust composition Oxygen 43% Silicon 21% Aluminium 10% Calcium 9% Iron 9% Magnesium 5% Titanium 2% Nickel 0. ... Photo taken during the French 1999 eclipse A solar eclipse occurs when the Moon passes in front of the Sun and obscures it totally or partially. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Statue of Quetzalcoatl Quetzalcoatl (feathered snake or plumed serpent; in Nahuatl: Ketsalkoatl; in Spanish: Quetzalcóatl) is the Nahuatl name for the Feathered-Serpent deity of ancient Mesoamerica, one of the main gods of many Mexican and northern Central American civilizations and also the name given to some Toltec rulers... Plan of Tenochtitlan (Dr Atl) Mexico City statue commemorating the foundation of Tenochtitlan Tenochtitlan (pronounced ) or, alternatively, Mexico-Tenochtitlan, was the capital of the Aztec empire, which was built on an island in Lake Texcoco in what is now central Mexico. ... Pope Leo XIII, born Vincenzo Gioacchino Raffaele Luigi Pecci (March 2, 1810 – July 20, 1903), was Pope of the Roman Catholic Church, having succeeded Blessed Pius IX on February 20, 1878 and reigning until his own death. ... The Pope (from Greek: pappas, father; from Latin: papa, Papa, father) is the head of the Catholic Church, which considers him the successor of St. ... Pope John Paul II (Latin: ), born Karol Józef Wojtyła (May 18, 1920 – April 2, 2005) reigned as pope of the Roman Catholic Church for almost 27 years, from October 16, 1978 until his death, making his the second-longest pontificate. ... John Adams (October 30, 1735 – July 4, 1826) was the first (1789–1797) Vice President of the United States, and the second (1797–1801) President of the United States. ... Thomas Jefferson (April 13, 1743 N.S. – July 4, 1826) was the third President of the United States (1801–1809), author of the Declaration of Independence (1776), and one of the most influential Founders of the United States. ... It has been suggested that Targeted killing be merged into this article or section. ... Abraham Lincoln (February 12, 1809 – April 15, 1865), sometimes called Abe Lincoln and nicknamed Honest Abe, the Rail Splitter, and the Great Emancipator, was the 16th President of the United States (1861 to 1865), and the first president from the Republican Party. ... John Fitzgerald Kennedy (May 29, 1917 – November 22, 1963), often referred to as John F. Kennedy, JFK, or Jack Kennedy, was the 35th President of the United States. ... A popular myth relates a number of coincidences having to do with US Presidents Abraham Lincoln and John F. Kennedy. ...

Separated twins and coincidences

A particular coincidental phenomenon relates to separated (usually identical) twins: a pair of twins are put up for adoption and are separated; they then follow parallel lives - names of family members, jobs taken, equipment owned (cars in particular). Upon finally meeting they discover the similarities and the story appears in the media. It is unclear what proportion of the total twins so separated belong to this category. Fraternal twin boys in the tub The term twin most notably refers to two individuals (or one of two individuals) who have shared the same uterus (womb) and usually, but not necessarily, born on the same day. ... Adoption is the legal act of permanently placing a child with a parent or parents other than the birth parents. ...

Coincidences and Conspiracies

The use or occurrence of coincidences or seemingly linked events appears to play a certain part in the development of some conspiracy theories. However, two events may occur in close proximity (temporal, geographical or otherwise) and still have no direct connection. Two persons in the same building or organisation may commit the same crime, for example, but be acting completely independently of each other. This proposed logo for the Information Awareness Office (a US governmental agency) was dropped due to fears that its pseudo-Masonic symbolism would provoke conspiracy theories. ...

See also

• Mathematical coincidence
• Coincidence theory
• Bible code
• Littlewood's law
• Post hoc ergo propter hoc
• Anomalous phenomenon
• Forteana
• Déjà vu
• Extra-sensory perception
• Randomness
• Synchronicity
• The Celestine Prophecy

This article needs to be cleaned up to conform to a higher standard of quality. ... The term coincidence theory is used by proponents of controversial theories (often called conspiracy theorists) to counter those who dismiss their claims; they mean to express thus that these dismissals rely on too many coincidences to be plausible. ... Bible codes, also known as Torah codes, are words, phrases and clusters of words and phrases that some people believe are meaningful and exist intentionally in coded form in the text of the Bible. ... Littlewoods Law states that individuals can expect a miracle to happen to them at the rate of about one per month. ... Post hoc ergo propter hoc is Latin for after this, therefore because of this. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Charles Fort, 1920 Charles Hoy Fort (August 6, 1874 - May 3, 1932), writer and researcher into anomalous phenomena, was the son of an Albany grocer of Dutch ancestry. ... The term déjà vu (French: already seen, also called paramnesia) describes the experience of feeling that one has witnessed or experienced a new situation previously. ... Extra-sensory perception, or ESP, is the name given to any ability to acquire information by means other than the five canonical senses (taste, sight, touch, smell, and hearing), or any other sense well-known to science (balance, proprioception, etc). ... It has been suggested that random number be merged into this article or section. ... Synchronicity is a word coined by the Swiss psychologist Carl Jung to describe the temporally coincident occurences of acausal events. Jung also spoke of synchronicity as being an acausal connecting principle (ie. ... The Celestine Prophecy is a 1993 novel by James Redfield. ...

References

• Jung, Carl G.: Synchronicity: An Acausal Connecting Principle. Princeton, N.J.: Princeton UP, 1973.
• Arthur Koestler: The Roots of Coincidence

Carl Gustav Jung (July 26, 1875 – June 6, 1961) (IPA:) was a Swiss psychiatrist and founder of Analytical Psychology. ... Arthur Koestler Arthur Koestler (September 5, 1905, Budapest – March 3, 1983, London) was a Hungarian polymath who became a naturalized British subject. ...

External links

• Historic Coincidence A collection of unusual coincidences in History
• Coincidences: Learning from Synchronicity
• Unlikely Events and Coincidence (ASTOP)
• The Power of Coincidence by David G. Myers (Skeptic)
• The Power of Coincidence by Jill Neimark (Psychology Today)
• The Coincidence Theorist's Guide to 9/11
• "How to Search and Find Whatever is Most Important to You", an article that shows how a process which searches for large combinations of keywords in Google results in seeming coincidences of insightful results with the searcher's deep personal interests.