Quantification Fallacies

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Undistributed Middle

Logically close Same family Often confused

Uses a shared middle term in a syllogism without properly connecting the categories, so the conclusion does not follow.

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Syllogistic Fallacies

Logically close Same family Similar wording

Uses a broken syllogism or category relationship so the conclusion does not logically follow.

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Illicit Major

Same family Often confused Similar wording

Draws a syllogistic conclusion that distributes the major term more broadly than the premises allow.

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Illicit Minor

Same family Often confused Similar wording

Draws a syllogistic conclusion that distributes the minor term more broadly than the premises allow.

4️⃣

Four-Term Fallacy

Same family Similar wording Same category

Uses a syllogism with four terms instead of three, often because a key term shifts meaning.

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Propositional Fallacies

Same family Similar wording Same category

A broader label for invalid moves in propositional logic where the conclusion does not validly follow from the premises.