Logic / Unit 3 Logic 102 short lesson, about 20 seconds
Undistributed Middle
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The idea
If the middle term is distributed in neither premise, the premises never connect — the classic formal fallacy.
In practice
All cats are mammals; all dogs are mammals; ∴ all cats are dogs. "Mammals" undistributed twice; the link never forms.
Where people slip
This is the engine of guilt-by-association reasoning: both share a category, therefore they're the same.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
- Nothing yet depends on this.
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