Intellectual property law is not about your right to control your copy of your idea - this is a right that we have just pointed out, does not need a great deal of protection. What intellectual property law is really about is about your right to control my copy of your idea. This is not a right ordinarily or automatically granted to the owners of other types of property. If I produce a cup of coffee, I have the right to choose whether or not to sell it to you or drink it myself. But my property right is not an automatic right both to sell you the cup of coffee and to tell you how to drink it. [emphasis added]
Thanks to David Warsh for the generic pointer to Boldrin-Levine (B-L).
One argument is that a publisher, like Microsoft, has the right to create terms of a contract that prohibit you from copying the software that you purchase. B-L say that this is an immoral contract, analogous to a contract where you agree to be a slave.
Another argument, to which I have been sympathetic, is that eliminating patents for pharmaceuticals would make it impossible for drug firms to recoup the costs of R&D. B-L say that innovation was high during past periods when drug patents were weak or nonexistent. My counter would be that those historical periods were not ones in which the drug industry conducted statistically valid trials.