Knowledge as a public good SPARC Open Access Newsletter, issue #139 November 2, 2009 by Peter Suber One of the most durable arguments for OA is that knowledge is and ought to be a public good. Here I don't want to restate or evaluate the whole argument, which is complex and has many threads. But I do want to pull at a few of those threads. What is a public good? In the technical sense used by economists, a public good is non-rivalrous and nonexcludable. A good is non-rivalrous when it's undiminished by consumption. We can all consume it without depleting it or becoming "rivals". Radio broadcasts are non-rivalrous; my reception doesn't block yours or vice versa. A good is non-excludable when consumption is available to all, and attempts to prevent consumption are generally ineffective. Radio broadcasts are non-excludable for people with the right equipment in the right area. Breathable air is non-excludable for this purpose even though a variety of barriers, from pollution to suffocation, could stop people from consuming it. Knowledge is non-rivalrous. Your knowledge of a fact or idea does not block mine, and mine does not block yours. Thomas Jefferson described this situation beautifully in an 1813 letter to Isaac McPherson: "If nature has made any one thing less susceptible than all others of exclusive property, it is the action of the thinking power called an idea....Its peculiar character...is that no one possesses the less, because every other possesses the whole of it. He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening mine." (See H.A. Washington, ed., The Writings of Thomas Jefferson, printed by the United States Congress, 1853-54, vol. VI, p. 180.) George Bernard Shaw also described it: "If you have an apple and I have an apple and we exchange apples then you and I will still each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas." (I can't find a source for the Shaw quotation and would appreciate any help.) Knowledge is also non-excludable. We can burn books, but not all knowledge is from books. We can raise the barriers to knowledge, through prices or punishments, but that only creates local exceptions for some people or some knowledge. When knowledge is available to people able to learn it, from books, nature, friends, teachers, or their own senses and experience, attempts to stop them from learning it are generally unavailing.
