Review of Russell Hardin ’ s How do you know ? : the economics of ordinary knowledge

Although some people are curious and enjoy learning things about the world even if they are of only remote interest to their daily lives, most people are not very inquisitive and set out to gather information only on a need-to-know basis. In his latest book Russell Hardin argues that people are perfectly rational when they refrain from embarking on a quest for knowledge. Ignorance turns out to be bliss, not because possessing knowledge would be disturbing, but because we maximize our utility by not investing much in knowledge acquisition. The core of what Hardin calls his 'economic theory of ordinary knowledge' consists of the thought that costs and benefits influence what we come to know. His main thesis is that cost-benefit analysis explains why most non-scientists know very little about anything. Hardin puts this thesis to a somewhat unexpected use—to defend the idea that human beings are rational agents. The charge is that we often do stupid things and that this goes to show that we are not very rational. Hardin's response is that the stupidity is only apparent. Allegedly stupid actions may be due to our ignorance and ignorance is usually rational since for practical purposes it is often not worth the trouble to learn more (i.e., the returns on investment in knowledge are frequently negative). In light of the rationality of our ignorance, it would be foolish to insist that the actions really are irrational. Hardin applies these ideas to several domains including medicine, culture, and religion, which I only mention here, and morality and politics, on which I shall elaborate. In relation to politics Hardin uses his thesis of the rationality of ignorance—as I will call it—to explain why so many people defy the logic of collective action. His main example is voting. The chance that your vote will make a difference is very small. Even when the cost of voting is small, the negligible chance of making a difference makes voting irrational for most, if not all of us. In spite of this, many people do vote.