Logic / Unit 5 Logic 215 short lesson, about 20 seconds
Conditional Proof
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The idea
To prove p ⊃ q: assume p in an indented sub-proof, derive q, then discharge — the conditional p ⊃ q exits to the main line.
In practice
You prove a promise by keeping it hypothetically.
Where people slip
Once discharged, nothing inside the indented scope may ever be cited again. The assumption is spent.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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