Equivocation

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 within an argument.[1][2]

It is a type of ambiguity that stems from a phrase having two distinct meanings, not from the grammar or structure of the sentence.[1]

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.[1]

The first instance of "man" implies the entire human species, while the second implies just those who are male.

See also

• Antanaclasis, a related purposeful rhetorical device
• Circumlocution
• Etymological fallacy
• Evasion (ethics)
• Fallacy of four terms
• False equivalence
• If-by-whiskey
• Mental reservation
• Persuasive definition
• Plausible deniability
• Principle of explosion
• When a white horse is not a horse

References

1. 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.
2. 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