Sure, I completely agree that a book discussing porn vs art can't literally start with definitions they way a math book can, that's too narrow. But if it wishe

Sure, I completely agree that a book discussing porn vs art can't literally start with definitions they way a math book can, that's too narrow. But if it wishes to use an existing word like "art" in a new sense, for instance to claim that all portrayal of humans is inherently pornographic, then IMHO it needs to be very careful to distinguish this from pre-existing meanings. The fact that some building on campus has "art" chiseled into the marble cannot be assumed to already imply agreement with some new meaning you invented 5 pages ago, a meaning which would have been very surprising to the guys who sponsored the building. Even if you ultimately make a convincing case that the sense you describe is somehow more correct/useful/interesting than other ones, or encompasses them, you've got to act as if you haven't yet shown that. That's what I meant he should have learned in math class. And really the more honest course is to introduce new words for new concepts, not to try to muddle older ones, as Said successfully did. But, to be fair, I didn't finish the book.