logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...

, equivocation ("calling two different things by the same name") is an

informal fallacy Informal fallacies are a type of incorrect argument in natural language. The source of the error is not just due to the ''form'' of the argument, as is the case for formal fallacies, but can also be due to their ''content'' and ''context''. Falla ...

resulting from the use of a particular word/expression in multiple

senses A sense is a biological system used by an organism for sensation, the process of gathering information about the world through the detection of stimuli. (For example, in the human body, the brain which is part of the central nervous system rec ...

within an argument. It is a type of

ambiguity Ambiguity is the type of meaning in which a phrase, statement or resolution is not explicitly defined, making several interpretations plausible. A common aspect of ambiguity is uncertainty. It is thus an attribute of any idea or statement ...

that stems from a phrase having two or more distinct meanings, not from the grammar or structure of the sentence.

Fallacy of four terms

Equivocation in a

syllogism A syllogism ( grc-gre, συλλογισμός, ''syllogismos'', 'conclusion, inference') is a kind of logical argument that applies deductive reasoning to arrive at a conclusion based on two propositions that are asserted or assumed to be true. ...

(a chain of reasoning) produces a

fallacy of four terms The fallacy of four terms ( la, quaternio terminorum) is the formal fallacy that occurs when a syllogism has four (or more) terms rather than the requisite three, rendering it invalid. Definition Categorical syllogisms always have three terms: : ...

(). Below are some examples: : Since only man

uman Uman ( uk, Умань, ; pl, Humań; yi, אומאַן) is a city located in Cherkasy Oblast in central Ukraine, to the east of Vinnytsia. Located in the historical region of the eastern Podolia, the city rests on the banks of the Umanka River ...

is rational. : And no woman is a man

ale Ale is a Type of beer, type of beer brewed using a Warm fermentation, warm fermentation method, resulting in a sweet, full-bodied and fruity taste. Historically, the term referred to a drink brewed without hops. As with most beers, ale typicall ...

: Therefore, no woman is rational. The first instance of "man" implies the entire human species, while the second implies just those who are male. : A feather is light ot heavy : What is light

right Rights are law, legal, social, or ethics, ethical principles of Liberty, freedom or entitlement; that is, rights are the fundamental normative rules about what is allowed of people or owed to people according to some legal system, social convent ...

cannot be dark. : Therefore, a feather cannot be dark. In the above example, distinct meanings of the word "light" are implied in contexts of the first and second statements. : All jackasses ale donkeyhave long ears. : Carl is a jackass nnoying person : Therefore, Carl has long ears. Here, the equivocation is the metaphorical use of "jackass" to imply a simple-minded or obnoxious person instead of a male donkey.

Motte-and-bailey fallacy

Equivocation can also be used to conflate two positions which share similarities, one modest and easy to defend and one much more controversial. The arguer advances the controversial position, but when challenged, they insist that they are only advancing the more modest position.

References

{{Fallacies Verbal fallacies Ambiguity

Fallacy of four terms

Motte-and-bailey fallacy

See also

References