Logic / Unit 6 Logic 277 short lesson, about 20 seconds
"Only," "Except," and Superlatives
Captions available
The idea
Identity unlocks exact-count and exclusivity claims.
In practice
"Only Alice passed": Pa · (x)(Px ⊃ x = a). "Alice is tallest" (Txy: x is taller than y): (x)((Px · x ≠ a) ⊃ Tax).
Where people slip
These translations run long. Build them clause by clause — the existence claim, then the exclusion clause.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
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