Logic / Unit 3 Logic 074 short lesson, about 20 seconds
Quality
Captions available
The idea
Quality is whether a statement affirms class membership (affirmative: A, I) or denies it (negative: E, O).
In practice
Quantity plus quality uniquely fixes the form: universal + negative = E.
Where people slip
"Quality" here has nothing to do with goodness. It's affirm-or-deny, nothing more.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
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