Still. People have gone to jail for copyright infringement, so I doubt at least they would feel like laughing at the idea that copyright exists.

Take tangible land, your exclusive use of it has boundaries, for example airspace rights or mineral rights. It is all made up.

The difference is tangible v intangible, but in either case the rights are made up.

How would you prove the existence of the universe? Do we not need a bigger universe that contains ours? And so forth? (Don't mention the big bang, which is a bunch of non-falsifiable formulas.)

You keep using these words, ontology and epistemology. I don't think they mean what you think they mean.

>If copyright could exist, then a copyright for the copyright must be able to exist, and it'd be turtles all the way down

This doesn't make any sense.

First, not all things that exist are covered by copyright or have a copyright about them existing (air exists, but doesn't have a copyright. Neither do slugs, pebbles, Uranus, and other existing things).

Copyright is just sets of laws dictating ability to copy, distribute, and so on. It doesn't need a copyright for itself, and even if it did, the regular terms for reproducing any other legal code would suffice.

>Copyright, as intellectual property, is entirely made up as all other intellectual property is.

All human laws and conventions are made up. Doesn't mean anything - copyright is still enforceable with very real prison buildings, cells, and bars - and if resisting arrest for it, very tangible police battons, tasers, and bullets are not out of question either.