IP law is unlibertarian and unjustified. I realized this myself after trying, and failing, for years to figure out a way to justify IP and square it with libertarian principles. IP is a type of systematic redistribution of property rights, contrary to Lockean homesteading rules, that can only be implemented by the state and its legislation. So the IP libertarians have nothing left but the tired old arguments of the type you might hear dashed off in law school or in a mainstream economics class.
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I find it disappointing that these debates tend to be as crude as those related to gun control. Neither is a black and white issue as either extreme ha, AFAICS, serious net negative effects on utility. Until this is acknowledged, we can't move the debate to the real issue of which rules maximize utility and how to best test and measure such rules.