Duck test

Duck test
A duck

The duck test is a humorous term for a form of inductive reasoning. This is its usual expression:

If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.

The test implies that a person can identify an unknown subject by observing that subject's habitual characteristics. It is sometimes used to counter abstruse arguments that something is not what it appears to be.

Contents

History

Indiana poet James Whitcomb Riley (1849–1916) may have coined the phrase when he wrote "when I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck."[1][2] The phrase may also have originated much later with Emil Mazey, secretary-treasurer of the United Auto Workers, at a labor meeting in 1946 accusing a person of being a communist.[3]

The term was later popularized in the United States by Richard Cunningham Patterson Jr., United States ambassador to Guatemala during the Cold War in 1950, who used the phrase when he accused the Jacobo Arbenz Guzmán government of being Communist. Patterson 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."[4]

Later references to the duck test include Cardinal Richard Cushing's, who used the phrase in 1964 in reference to Fidel Castro.[5][6]

Variants include Douglas Adams' Dirk Gently's Holistic Detective Agency:

If it looks like a duck, and quacks like a duck, we have at least to consider the possibility that we have a small aquatic bird of the family anatidae on our hands.

The Liskov Substitution Principle in computer science is sometimes expressed as a counter-example to the duck test:

If it looks like a duck and quacks like a duck but it needs batteries, you probably have the wrong abstraction.[7]

See also

Notes

References

  • Christy, Howard Chandler; Ethel Franklin Betts (1982), The complete works of James Whitcomb Riley 
  • Denver, Joseph; Ethel Franklin Betts (1965), Cushing of Boston: A Candid Portrait 
  • Immerman, Richard H. (1982), The CIA in Guatemala: The Foreign Policy of Intervention, Austin, Texas: University of Texas Press 

Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Duck Test — Sieht aus wie eine Ente, schwimmt wie eine Ente, quakt wie eine Ente: Das ist eine Ente Der Terminus Ententest (englisch duck test) beschreibt eine Methode einer analogen Begriffsbestimmung, wonach jemand versucht, die Natur eines bestimmten… …   Deutsch Wikipedia

  • duck test — noun for application of common sense and/or intuition regardless of technical parameters …   Wiktionary

  • Duck typing — Type systems Type safety Inferred vs. Manifest Dynamic vs. Static Strong vs. Weak Nominal vs. Structural Dependent typing Duck typing Latent typing Linear typing Uniqueness typing …   Wikipedia

  • Test du canard — positif. Le test du canard est une certaine forme d induction humoristique que l on peut énoncer ainsi : « Si ça ressemble à un canard, si ça nage comme un canard et si ça cancane comme un canard, c est qu il s agit sans doute d un… …   Wikipédia en Français

  • Duck (disambiguation) — Contents 1 Animals 2 Transportation 3 Computer software 4 …   Wikipedia

  • Duck — This article is about the bird. For duck as a food, see Duck (food). For other meanings, see Duck (disambiguation). Duckling redirects here. For other uses, see Duckling (disambiguation). Ducks …   Wikipedia

  • Duck Dodgers (TV series) — Duck Dodgers Format Animated television series Developed by Spike Brandt Tony Cervone Directed by Spike Brandt Tony Cervone Voices of Joe Alaskey Bob Bergen …   Wikipedia

  • Duck, You Sucker! — (Giù la testa) Original poster for American release Directed by Sergio Leone …   Wikipedia

  • Duck and Cover (The Wire) — Duck and Cover The Wire episode Episode no. Season 2 Episode 8 …   Wikipedia

  • duck soup — {n.}, {slang} 1. A task easily accomplished or one that does not require much effort. * /That history test was duck soup./ 2. A person who offers no resistance; a pushover. * /How s the new history teacher? He s duck soup./ …   Dictionary of American idioms

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”