Logic / Unit 6 Logic 260 short lesson, about 20 seconds
The Existential Quantifier
Captions available
The idea
(∃x)Fx says: at least one individual x is F.
In practice
(∃x)Ux — something is a unicorn. False, but perfectly well-formed.
Where people slip
"At least one," exactly as in video 071. The two quantifiers are the whole inventory.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for Logic