Commonwealth of Knowledge
"If you stand in front of the McKeldin Library at the University of Maryland, you’ll see a quotation from Thomas Jefferson carved on one of the stones: “Knowledge is the common property of mankind.” Well, I think Mr. Jefferson was right. Once knowledge exists, it is non-rival, which means it has a zero opportunity cost. As we know from studying price theory, price is supposed to measure opportunity cost, and if opportunity cost is zero, then price should be zero.
Certainly, new knowledge, even though it should be free, does have a cost of production. Sometimes that cost of production is substantial, as with the space program’s discovery that there’s no life on Mars. On the other hand, a new insight could occur to you while you’re lying in bed staring at the ceiling and cost absolutely nothing, as was the case with Renee Descartes’ invention of analytic geometry.
Many new discoveries are accidental. Others are motivated by the joy and excitement of research, independent of any material motivation. Yet the dominant view is that unless knowledge is kept scarce enough to have a significant price, nobody in the market will have an incentive to produce it. Patent monopolies and intellectual property rights are urged as the way to provide an extrinsic reward for knowledge production.
Even within that restricted vision, keeping knowledge scarce still makes very little sense, because the main input to the production of new knowledge is existing knowledge. If you keep existing knowledge expensive, that’s surely going to slow down the production of new knowledge." (http://peopleandplace.net/featured_voices/2010/10/19/sustaining_our_commonwealth)