Logic / Unit 2 Logic 046 short lesson, about 20 seconds
Intension and Extension
Captions available
The idea
A term's intension is its defining attributes; its extension is the set of things it picks out.
In practice
"Triangle" — intension: closed three-sided figure; extension: every triangle there is.
Where people slip
Empty extension doesn't mean no meaning. "Unicorn" has a perfectly clear intension.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Builds on
Unlocks
Something wrong in this lesson? Flag it · Sources for Logic