A mallard (Anas platyrhynchos)

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.

History [edit]

Emil Mazey, the secretary-treasurer of the United Automobile Workers for 33 years, said at a labor meeting in 1946:

I can’t prove you are a Communist. But when I see a bird that quacks like a duck, walks like a duck, has feathers and webbed feet and associates with ducks—I’m certainly going to assume that he IS a duck.^[1]

References [edit]

• 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 

See also [edit]

• Duck typing
• Elephant test
• I know it when I see it
• Identity of indiscernibles
• Occam's razor
• To call a spade a spade
• Turing test
• Zebra (medicine)