"Crank" is a pejorative term used for a person who holds an unshakable belief that most of his or her contemporaries consider to be false. A crank belief is so wildly at variance with those commonly held as to be ludicrous. Cranks characteristically dismiss all evidence or arguments which contradict their own unconventional beliefs, making rational debate a futile task, and rendering them impervious to facts, evidence, and rational inference.
Common synonyms for "crank" include crackpot and kook. A crank differs from a fanatic in that the subject of the fanatic's obsession is either not necessarily widely regarded as wrong or not necessarily a "fringe" belief. Similarly, the word quack is reserved for someone who promotes a medical remedy or practice that is widely considered to be ineffective; this term however does not imply any deep belief in the idea or product they are attempting to sell. Crank may also refer to an ill-tempered individual or one who is in a bad mood, but that usage is not the subject of this article.
Although a crank's beliefs seem ridiculous to experts in the field, cranks are sometimes very successful in convincing non-experts of their views. A famous example is the Indiana Pi Bill where a state legislature nearly wrote into law a crank result in geometry.
Old English cranc- is preserved in modern English crankshaft, and obsolete crancstæf "a weaver's instrument". It is from a Proto-Germanic stem *krank- meaning "bend". German krank has a modern meaning of "sick, ill", evolved from a former meaning "weak, small". English crank in its modern sense is first recorded 1833, and cranky in a sense of "irritable" dates from 1821. The term was popularised in 1872 for being applied to Horace Greeley who was ridiculed during his campaign for the U.S. presidency. In 1882, the term was used to describe Charles Guiteau who shot U.S. president James Garfield.
In 1906, Nature offered essentially the same definition which is used here:
A crank is defined as a man who cannot be turned.
— Nature, 8 Nov 1906, 25/2
The term "crank" (or "krank") was once the favored term for spectators at sporting events, a term later supplanted by "fans". By implication, the "kranks in the bleaching boards" think they know more about the sport than do its participants. There is more discussion of this term in The Dickson Baseball Dictionary, by Paul Dickson.
The word crackpot apparently also first appeared in 1883:
My aunty knew lots, and called them crack-pots.
— Broadside Ballad, 1883
As noted in Webster's New Collegiate Dictionary, the terms "crackpot", "crackbrain" and "cracked" are synonymous, and suggest a metaphorically "broken" head. The terms "crazy" and "crazed" also originally meant "broken" and derive from the same root word as "cracked". The dictionary gives no indication that "pate" and "pot" have the same root, despite their apparent similarity, and implied colloquial use of "pot" to mean "head" in the word "crackpot". However, the term "craze" is also used to refer to minute cracks in pottery glaze, again suggesting the metaphorical connection of cracked pots with questionable mental health.
The term kook appears to be much more recent. The adjectival-form, kooky, was apparently coined as part of American teen-ager (or beatnik) slang, which derives from the pejorative meaning of the noun cuckoo. In late 1958, Edd Byrnes first played a hair-combing parking lot attendant called "Kookie" on 77 Sunset Strip. The noun-form kook, may have first appeared in 1960 in Britain's Daily Mail newspaper:
A kook, Daddy-O, is a screwball who is 'gone' farther than most
— Daily Mail, 22 Aug 1960, 4/5
The crank and abstract truth 
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The term crank is often applied to persons who contradict rigorously proven mathematical theorems, such as the impossibility of squaring the circle by ruler and compass, or who deny extremely well established physical theories, such as the special theory of relativity, conservation of mass-energy, or a spheroid earth (See Flat Earth Society). More engineer-minded cranks may claim to have invented a magic compression algorithm or a perpetual motion / free energy machine.
However this doesn't apply to mathematics, which is not subject to such retractions of established results, notwithstanding nineteenth and early twentieth century discoveries in mathematical logic which may be popularly misunderstood as having overthrown prior mathematics. Rather, it is correct to say that mathematicians have gradually developed more encompassing abstractions which do not invalidate earlier mathematics but do often reinterpret them in new and expanded contexts. That is, previous mathematical knowledge has been enriched, not overthrown, by such discoveries as non-Euclidean geometry or Gödel's incompleteness theorems.
The mathematical cases provide a baseline for application of the epithet, since the nature of mainstream or for that matter learned, scientific opinion can change over time; however, irrationally rejecting established mathematical truth is archetypical crankery. Typically a crank is impervious to contrary evidence. Those who have studied the phenomenon of crankery agree that this is the essential defining characteristic of the crank: being impervious to facts, evidence, and rational inference.
Common characteristics of cranks 
The second book of the mathematician and popular author Martin Gardner was a study of crank beliefs, Fads and Fallacies in the Name of Science. More recently, the mathematician Underwood Dudley has written a series of books on mathematical cranks, including The Trisectors, Mathematical Cranks, and Numerology: Or, What Pythagoras Wrought. And in a 1992 UseNet post, the mathematician John Baez humorously proposed a checklist, the Crackpot index, intended to diagnose cranky beliefs regarding contemporary physics.
According to these authors, virtually universal characteristics of cranks include:
- Cranks overestimate their own knowledge and ability, and underestimate that of acknowledged experts.
- Cranks insist that their alleged discoveries are urgently important.
- Cranks rarely, if ever, acknowledge any error, no matter how trivial.
- Cranks love to talk about their own beliefs, often in inappropriate social situations, but they tend to be bad listeners, being uninterested in anyone else's experience or opinions.
Some cranks lack academic achievement, in which case they typically assert that academic training in the subject of their crank belief is not only unnecessary for discovering the truth, but actively harmful because they believe it poisons the minds by teaching falsehoods. Others greatly exaggerate their personal achievements, and may insist that some achievement (real or alleged) in some entirely unrelated area of human endeavor implies that their cranky opinion should be taken seriously.
Some cranks claim vast knowledge of any relevant literature, while others claim that familiarity with previous work is entirely unnecessary; regardless, cranks inevitably reveal that whether or not they believe themselves to be knowledgeable concerning relevant matters of fact, mainstream opinion, or previous work, they are not in fact well-informed concerning the topic of their belief.
In addition, many cranks:
- seriously misunderstand the mainstream opinion to which they believe that they are objecting,
- stress that they have been working out their ideas for many decades, and claim that this fact alone entails that their belief cannot be dismissed as resting upon some simple error,
- compare themselves with Galileo or Copernicus , implying that the mere unpopularity of some belief is in itself evidence of plausibility,
- claim that their ideas are being suppressed, typically by secret intelligence organizations, mainstream science, powerful business interests, or other groups which, they allege, are terrified by the possibility of their revolutionary insights becoming widely known,
- appear to regard themselves as persons of unique historical importance.
- exhibit a marked lack of technical ability,
- misunderstand or fail to use standard notation and terminology,
- ignore fine distinctions which are essential to correctly understand mainstream belief.
That is, cranks tend to ignore any previous insights which have been proven by experience to facilitate discussion and analysis of the topic of their cranky claims; indeed, they often assert that these innovations obscure rather than clarify the situation.
In addition, cranky scientific theories do not in fact qualify as theories as this term is commonly understood within science. For example, crank theories in physics typically fail to result in testable predictions, which makes them unfalsifiable and hence unscientific. Or the crank may present their ideas in such a confused, not even wrong manner that it is impossible to determine what they are actually claiming.
Perhaps surprisingly, many cranks may appear quite normal when they are not passionately expounding their cranky belief, and they may even be successful in careers unrelated to their cranky beliefs.
A counter argument is that the term itself lacks either a theoretical or scientific foundation that would otherwise disambiguate those who may possess a genuine psychological predisposition to explain a set of abnormal social behaviors of a person thought to be a crank.
For example, a person exhibiting crank behavior may have previously been diagnosed with a cognitive deficit, such as nonverbal learning disorder or autism, that would otherwise cause the person to pursue or invent theories that enable them to circumnavigate the cognitive impairments associated with their condition. These types of cognitive deficits would have gone undiagnosed in certain historical figures that were responsible for creating new foundational theoretic frameworks that are prevailing in today's mainstream academic and scientific research communities.
Internet cranks 
The rise of the Internet has given another outlet to people well outside the mainstream who may get labeled cranks due to internet postings or websites promoting particular beliefs. There are a number of websites devoted to listing people as cranks. Community-edited websites like Wikipedia have been described as vulnerable to cranks.
Science fiction author and critic Bruce Sterling noted in his essay in CATSCAN 13:
Online communication can wonderfully liberate the tender soul of some well-meaning personage who, for whatever reason, is physically uncharismatic. Unfortunately, online communication also fertilizes the eccentricities of hopeless cranks, who at last find themselves in firm possession of a wondrous soapbox that the Trilateral Commission and the Men In Black had previously denied them.
Crank magnetism 
Crank magnetism is a term popularized by physiologist and blogger Mark Hoofnagle to describe the propensity of cranks to hold multiple irrational, unsupported or ludicrous beliefs that are often unrelated to one another. Crank magnetism may be considered to operate wherever a single person propounds a number of unrelated denialist conjectures, poorly supported conspiracy theories, or pseudoscientific claims. Thus, some of the common crank characteristics (see above)— such as the lack of technical ability, ignorance of scientific terminology, and claims that alternative ideas are being suppressed by the mainstream— may be operating on and manifested in multiple orthogonal assertions. Blogger Luke Scientiæ has commented on the relationship between the number of unrelated claims that magnetic cranks make and the extent of their open hostility to science. He has also coined the phrase "magnetic hoax" in relation to hoax claims that attract multiple crank interpretations.
See also 
- Crank at Merriam-Webster Online Dictionary
- John Baez, New improved crackpot index (an update to the 1992 list, 26 August 1998, sci.physics (archived message on Google Groups).
- Hodges, Wilfrid (1998). "An Editor Recalls Some Hopeless Papers". The Bulletin of Symbolic Logic 4 (1): 1–16. doi:10.2307/421003. JSTOR 421003. A paper describing several attempts at disproving Cantor's diagonal argument, looking at the flaws in their arguments and reasoning.
- "Fact or fiction? Who contributes to Wikipedia? Despite ... ", Global Agenda, March 12, 2007, Retrieved 23 April 2010
- "Wikipedia.(Brief Article)". Booklist. September 15, 2002.
- CATSCAN 13: "Electronic Text" (Bruce Sterling, SF Eye) Retrieved 8 August 2012
- Hoofnagle, Mark. "Crank Magnetism". Retrieved 29 June 2011.
- Luke Scientiæ. "A Few Comments on Crank Magnetism". Retrieved 15 August 2011.
- Luke Scientiae. "The Magnetic Hoax: The Giant Hoax as an Example". Retrieved 15 August 2011.
Further reading 
- Dudley, Underwood (1987). A Budget of Trisections. New York: Springer-Verlag. ISBN 0-387-96568-8.
- Dudley, Underwood (1992). Mathematical Cranks. Washington, D.C.: Mathematical Association of America. ISBN 0-88385-507-0.
- Dudley, Underwood (1996). The Trisectors. Washington, D.C.: Mathematical Association of America. ISBN 0-88385-514-3.
- Dudley, Underwood (1997). Numerology: Or, What Pythagoras Wrought. Washington, D.C.: Mathematical Association of America. ISBN 0-88385-524-0.
- Dudley, Underwood (2008). On Jargon: How to Call a Crank a Crank (and Win If You Get Sued). The UMAP Journal, 29.1.
- Eves, Howard (1972). Mathematical Circles Squared; A Third Collection of Mathematical Stories and Anecdotes. Boston: Prindle, Weber & Schmidt. ISBN 0-87150-154-6.
- Gardner, Martin (1957). Fads and Fallacies in the Name of Science. New York: Dover. ISBN 0-486-20394-8. LCCN 57-3844
- Williams, William F. (Editor) (2000). Encyclopedia of Pseudoscience: From Alien Abductions to Zone Therapy Facts on File ISBN 0-8160-3351-X
- Kossy, Donna. Kooks: A Guide to the Outer Limits of Human Belief, Los Angeles: Feral House, 2001 (2nd ed. exp. from 1994). (ISBN 978-0-922915-67-5)
- Kruger, Justin; David Dunning (1989). "Unskilled and Unaware of It: How Difficulties in Recognizing One's Own Incompetence Lead to Inflated Self-Assessments" (PDF). J. Pers. And Soc. Psych. 71: 1121–1134.
- Crank Dot Net Cranks and their theories listed and categorised.