Prof. Richard Epstein explains Why Libertarians Shouldn't Be (Too) Skeptical About Intellectual Property.

His conclusion:

In closing, it is important to remember that there are vast differences between the way in which the law treats various forms of property. That level of variation is found in the different treatment for tangible objects, such as land, water, chattels, air rights and the like.11 It is also true that a similar variation exists among the various forms intellectual property rights, including those close twins copyright and patent. Yet these differences do not signal any disintegration in the overall conception of property rights. Instead they do exactly the opposite. Different resources will be effectively exploited only if subject to different property regimes. Whether we start from the state of nature or the current complex definition of property rights, we should always be on the lookout for strong social improvements that cannot be achieved by voluntary means. In those cases, purposive innovation on property rights, by either courts or legislatures seems appropriate. Yet no belief in natural rights should prove so strong as to require us have allegiance to any set of rights in any resource when a credible showing can be made that some social reconfiguration of those rights will lead to new property rights assignments that improve the lot of all in roughly equal proportion. It is this criterion that explains the variation in the different forms of property rights. It is this criterion that dominates any intuitive appeal to natural rights in property. And it is this criterion which explains why the law of intellectual property in all its forms should be subject to constant analysis and review, but not to any a priori attack on the supposed inferiority intellectual property rights to those in tangible objects. The categorical libertarian objection to creation of intellectual property rights should be emphatically rejected.

11 I discuss this point in Richard A. Epstein, Intellectual Property: Old Boundaries and New Frontiers (Addison C. Harris Lecture) 76 Ind. L. J. 803 (2001).