Equivocation and Ambiguity

Some of the most subtle fallacies exploit the flexibility of language itself. Equivocation occurs when a word or phrase is used with different meanings at different points in an argument, creating the illusion of a valid logical connection. Ambiguity — whether lexical, syntactic, or contextual — can be exploited to make arguments appear stronger than they are. These fallacies are particularly relevant to the LNAT because the test rewards precise reading and the ability to detect when language is doing the work that logic should be doing.

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What Is Equivocation?

Equivocation is a fallacy in which a key term is used with two or more different meanings within the same argument, and the argument's apparent validity depends on the shift in meaning.

Structure

Step	What happens
Premise 1	Uses term T in meaning A
Premise 2	Uses term T in meaning B
Conclusion	Draws on both premises as though T has the same meaning throughout
The flaw	The conclusion only follows if T means the same thing in both premises — but it does not