In logic, equivocation ('calling two different things by the same name') is an informal fallacy resulting from the use of a particular word/expression in multiple senses throughout an argument leading to a false conclusion. Abbott and Costello's "Who's on first?" routine is a well known example of equivocation.
Below is an example of equivocation in a syllogism (a logical chain of reasoning).
- Since only man [human] is rational,
- and no woman is a man [male],
- therefore, no woman is rational.
The first instance of "man" implies the human species, while the second implies just the males.
- Damer, T. Edward (21 February 2008). Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments. Cengage Learning. pp. 121–123. ISBN 0-495-09506-0.
- Fischer, D. H. (June 1970), Historians' fallacies: toward a logic of historical thought, Harper torchbooks (first ed.), New York: HarperCollins, p. 274, ISBN 978-0-06-131545-9, OCLC 185446787
- Curtis, Gary (n.d.). "Logical Fallacy: Equivocation". The Fallacy Files. Retrieved 17 July 2017.
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