I’m already so done with this course.
My textbook:
p: “The weather is bad.”
Exercise:
Represent “the weather is good” using logical symbols.
Me: How am I supposed to answer that? You didn’t give me a letter for that. I guess I’ll use q?
Expected answer: ~p
THIS IS LITERALLY THE CLASS ABOUT LOGIC DHDJFBDHDJDHDHDH
Who let neurotypicals write a logic textbook istg
the set that contains everything is not a (proper) set, according to 20th century mathematicians.
That’s because it would contain “impossible” elements, i.e. elements for which contradictory statements both hold true. That shakes the foundations of maths, so it’s typically excluded from maths, and not called a “set”. (it’s called “class” instead.)
Fair enough. Standard set theory would not allow for such a set to exist, and it would have to either be constructed in an alternate set theory with different axioms or, as you said, called a ‘class.’
But it’s not as if the concept isn’t there, it just needs a little special treatment.