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fallacy

FAL-uh-see /ˈfæl.ə.si/

nounB2GRESATGMATACT

academicgeneral

A mistaken belief or a flaw in reasoning that renders an argument invalid.

A fallacy is not just a factual error; it is an error in the path of reasoning itself.

The story behind the word. Derived from Latin 'fallacia' ('deceit' or 'trickery'), rooted in 'fallere' ('to deceive'). A fallacy is literally an argument that tricks the mind into accepting a false deduction.

Word relationships

misconception: A misconception is a wrong idea held by a person, whereas a fallacy is an error in logical reasoning.
sophism: A sophism is a fallacious argument constructed intentionally to deceive.

truth: Truth represents factual accuracy and valid sound reasoning, opposing fallacious reasoning.

Commonly confused with

falsity: 'Falsity' refers to the state of being factually incorrect, while 'fallacy' refers to flawed logical reasoning.

Word family

fallacious (adjective): Containing or based on a fallacy.
fallaciously (adverb): In a logical errant manner.

Collocations

logical fallacy
commit a fallacy
fallacy of composition
patently false fallacy

Idioms & expressions

fallacy of central tendency
sunk cost fallacy

Example sentences

"Attacking the speaker's personal background rather than addressing their point is a classic ad hominem fallacy." Debate Analysis
"It is a common fallacy to assume that because two events happen together, one must have caused the other." Social Critique

Memory hook

FALL-acy makes an argument FALL apart. Flawed reasoning that trips you up.

When not to use

Avoid using 'fallacy' to describe a simple misstatement of fact (e.g., 'claiming Paris is in Italy is a fallacy'). It is better reserved for bad logical structure or deceptive argument tactics.

Fun facts

The Latin root 'fallere' gives us both 'fallacy' and 'false', as well as 'fallible'.