The duck test is a specific form of inductive reasoning whereby one can infer the nature of an unknown based upon its outwardly visible traits. More simply, the duck test can be explained this way: If a bird looks like a duck, swims like a duck and quacks like a duck, then you can infer that it is indeed a duck, even if it is not wearing a label that explicitly states its identity. // Induction or inductive reasoning, sometimes called inductive logic, is the process of reasoning in which the premises of an argument support the conclusion but do not ensure it. ...

While no one really invented the duck test since it is an inherent characteristic of human intuition, it seems to have been first termed and explicated during the Cold War in 1950 by Richard Patterson, United States Ambassador to Guatemala, in his accusation that the government of Jacobo Arbenz Guzmán was communist. Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are bipedal primates belonging to the mammalian species Homo sapiens (Latin for wise man or knowing man) under the family Hominidae (the great apes). ... Intuition is an unconscious form of knowledge. ... The Cold War (Russian: Холодная война Kholodnaya Voina) was the protracted geopolitical, ideological, and economic struggle that emerged after World War II between the global superpowers of the Soviet Union and the United States, supported by their military alliance partners. ... 1950 (MCML) was a common year starting on Sunday (link will take you to calendar). ... This is a list of ambassadors from the United States. ... Jacobo Arbenz Guzmán, pictured above with his wife, was the democratically elected, center-left agrarian reformist President of Guatemala. ... This article is about communism as a form of society and as a political movement. ...

He explained his reasoning as follows:

"Suppose you see a bird walking around in a farm yard. This bird has no label that says 'duck'. But the bird certainly looks like a duck. Also, he goes to the pond and you notice that he swims like a duck. Then he opens his beak and quacks like a duck. Well, by this time you have probably reached the conclusion that the bird is a duck, whether he's wearing a label or not." (Immerman 1982, p. 102) The term duck test refers to a method of analogical comparison whereby one can infer the nature of an unknown based upon its outwardly visible traits. ...

To Patterson and other United States officials, many traits of the Arbenz government seemed to indicate that communists were infiltrating Arbenz regime. In their view, the Arbenz government's censorship of the dissident press, discrimination against private capital investment, anti-imperialist rhetoric, and leftist reforms such as agrarian reform and legalization of labor unions were considered dispositional characteristics of communists and thus evidence of the rising influence of communism in the Arbenz regime. U.S. officials did not need hard evidence of communist subversion to believe that the Arbenz government was communist, instead inferring the existence of communist subversion because agrarian reform (or agrarian revolution) was a significant factor in Mao Zedong's communist revolution in China leading communists attain power in 1949. The United States Central Intelligence Agency (CIA) was eventually authorized by President Dwight D. Eisenhower to sponsor a coup of the Arbenz government to eliminate the supposed communist threat, ultimately causing a bloody decades-long civil war. The examples and perspective in this article or section may not represent a worldwide view. ... Invest redirects here. ... Anti-imperialism is a current within the political left advocating the collapse of imperialism. ... In politics, left-wing, political left, leftism, or simply the left, are terms which refer (with no particular precision) to the segment of the political spectrum typically associated with any of several strains of socialism, social democracy, or liberalism (especially in the American sense of the word), or with opposition... Agrarian reform can refer either, narrowly, to government-initiated or government-backed redistribution of agricultural land (see land reform) or can refer more broadly to an overall redirection of the agrarian system of the country, which often includes land reform measures. ... A union (labor union in American English; trade union, sometimes trades union, in British English; either labour union or trade union in Canadian English) is a legal entity consisting of employees or workers having a common interest, such as all the assembly workers for one employer, or all the workers... Agrarian reform can refer either, narrowly, to government-initiated or government-backed redistribution of agricultural land (see land reform) or can refer more broadly to an overall redirection of the agrarian system of the country, which often includes land reform measures. ... The Chinese Civil War was a conflict in China between the Kuomintang (the Nationalist Party; KMT) and the Communist Party of China (CPC). ... This article does not cite its references or sources. ... A communist revolution is a social revolution inspired by the ideas of Marxism that aims to replace capitalism with communism, normally with socialism (public ownership over the means of production) as an intermediate stage. ... 1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ... CIA redirects here. ... The CIA Seal The Central Intelligence Agency (CIA) is an American intelligence agency, responsible for obtaining and analyzing information about foreign governments, corporations, and individuals, and reporting such information to the various branches of the U.S. Government. ... Dwight David Ike Eisenhower (October 14, 1890–March 28, 1969), American soldier and politician, was the 34th President of the United States (1953–1961) and supreme commander of the Allied forces in Europe during World War II, with the rank of General of the Army. ...

The term "duck test" is still frequently used to describe this process of attributing the identity of an unknown based on its traits.

Monty Python lampooned the "duck test" in their film Monty Python and the Holy Grail in order to show that faulty conclusions can be reached by this type of backwards reasoning. In the film, a woman is accused of being a witch. Since witches are burned at the stake, they must be made of wood, since it burns as well. Wood floats on water, as do ducks. Therefore, if the woman weighs the same as a duck, she must be able to float on water, which means she is made of wood, and consequently must be a witch. The Python team. ... Monty Python and the Holy Grail is a comedy film released in 1975. ... This article is part of the Witchcraft series. ... Burning of two sodomites at the stake outside Zürich, 1482 (Spiezer Schilling) Execution by burning has a long history as a method of punishment for crimes such as treason and for other unpopular acts such as heresy and the practice of witchcraft. ... Subfamilies Dendrocygninae Oxyurinae Anatinae Merginae For other uses, see Duck (disambiguation). ...

See also

• Duck typing, a computer science term
• Digesting Duck
• Identity of indiscernibles
• Turing Test

In computer science, duck typing is a term for dynamic typing typical of some programming languages, such as Smalltalk or Visual FoxPro, where a variables value itself determines what the variable can do. ... Vaucansons duck The Canard Digérateur or Digesting Duck was an automaton duck created by Jacques de Vaucanson in 1739. ... The identity of indiscernibles is an ontological principle that states that if there is no way of telling two entities apart then they are one and the same entity. ... The Turing test is a proposal for a test of a machines capability to perform human-like conversation. ...

Sources:

• Immerman, Richard H. (1982), The CIA in Guatemala: The Foreign Policy of Intervention, University of Texas Press, Austin, Texas