Denying the Antecedent
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This page is part of the EvoWiki encyclopedia of fallacies. |
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Synonyms
- Denial of the Antecedent
- Fallacious Modus Tollens
Explanation
"If A is true, then B is true; A is false, therefore B is false"
This argument is fallacious because the fact of 'A' being untrue is not enough reason to suggest 'B' is not true. Usually 'B' can be true for other reasons, not just 'A'.
This argument would only be valid if it is true that "if and only if A is true, B is true", which is normally not the case.
Examples
- "If you were an atheist, you would believe the theory of evolution.
- You are not an atheist.
- Thus, you must not believe in evolution."
This is clearly invalid, as demonstrated by the many religious people who accept evolution.
