What constitutes "art", and why? What's its purpose?
Practically every professor I've had teach the stuff begins with this question.
There are some words we derive from Greek to describe phenomena. Logos refers to logic, or logical arguments. Ethos refers to an appeal to ethics. And pathos is an appeal to emotions. I think art is primarily pathos, although it may have elements of logos or ethos to it. Art is generally meant to be something to be experienced. What a person thinks qualifies as art can vary a lot, but I think art is an expression of pathos at its core.
What's the point of art if you don't hold it to a standard?
The art is in the room to respond to the work as opposed to the art piece itself.
Everything's art, but it's up to ourselves to discern what is good art. The only standard there is to otherwise hold it to is consistency within the art form, but even that's more playing into "high art" as opposed to art itself.