Spoken like a true gentleman, and you raised a few good points. I still feel that there's a difference between physical property and "intellectual property" - probably because "intellectual property" is mostly licensed. It's the licensing that sets apart "intellectual property" and it's the giant, state support for enforcement of licenses that makes the difference. If we talked about people leasing or renting software or music, it might make more sense, but licensing something to a consumer, all the while encouraging them to think they've bought it, seems like a recipe for disaster.

The other thing about "intellectual property" is the distinct possibility of independent invention. Even if we disallow my use of my own capital hardware to make a duplicate via some state financed mechanism, there's still a very real possibility that someone else also invented the "intellectual property" in question. Several people invented the steam engine. Several people invented the telegraph, at more or less the same time. Someone in the Bronze age seems to have invented safety pins. Algorithms get independently discovered all the time - see KMP string matching for a classic, but there's certainly a lot of others. A bunch of people discovered continuations at different times. How do we stretch the idea of property to cover all this? This seems like it will lead to trouble.