Why Religious Beliefs Are Irrational, and Why Economists Should Care


by Bryan Caplan


Larry Iannaccone and his co-author Rodney Stark once wrote that the belief that society is getting less religious says "less about empirical fact than it does about secularization faith a faith that, despite a mountain of evidence to the contrary, sustains the conviction of many social scientists that religious institutions must soon decay..." In short, belief in secularization is just a religion.


Larry's critics were, unsurprisingly, not pleased. To tell people that their non-religious beliefs are just a religion is an insult. Why is it an insult? There isn't any nice way to answer, so I'll be blunt. It is an insult because the way that people form religious beliefs is so intellectually irresponsible that their conclusions are almost guaranteed to be false. People:


        accept their religious beliefs with little or no evidence


        accept religious beliefs that are contrary to the evidence


        accept religious beliefs without studying competing views


        are certain about religious beliefs that are dubious at best, and


        accept their religious beliefs not because they are intellectually compelling, but because they are emotionally comforting.


Forming non-religious beliefs in a religious way is irrational because forming any beliefs in a religious way is irrational.


Now I am not one of those people who says that modern science has disproven religion. If I said that, it would imply that two thousand years ago, there was not solid evidence against the claims that Jesus was born of a virgin and rose from the dead. But the counter-evidence has always been overwhelming. Everyone else is born of a non-virgin and stays dead. It is absurd to recognize an exception without overwhelming evidence, but all we have is the testimony of a few of his disciples. And yet not only do Christians believe these things; they often claim to know them with certainty, and get angry if you disagree. Christianity has always been irrational, and of course the same goes for Judaism, Islam, Greek mythology, Satanism, and belief in Santa Claus.


Larry has won a great deal of attention for his rational choice theory of religion. But if you look closely, he doesn't really have a rational choice theory of religion; he has a rational choice theory of group membership. As Larry occasionally admits, virtually everything that he says about religion applies just as well to fraternities, chess clubs, and football teams. Yes, belonging to a fraternity has costs and benefits; yes, competition between fraternities leads to more efficient outcomes. And both religions and fraternities have been known to use what Larry calls "bizarre" rules such as "You can't drink any alcohol," or "You can only drink alcohol," to exclude half-hearted members.


What Larry's research strangely neglects or, to use his word, "sidesteps" - is the differences between religions and fraternities. The most obvious of these, the 800-pound gorilla in the room, is doctrine. Fraternities don't have much of a doctrine; religions do. To ignore doctrine is to ignore the very thing that makes religion special and the main reason why critics of religion consider it irrational. Furthermore, to ignore doctrine is to sidestep the deepest objection to Larry's rational choice view of religion: How can you have a rational choice theory of irrational belief?


Larry's neglect of irrational beliefs is glaring because in the last decade economists have started to take irrationality seriously. Behavioral economists emphasize, for example, that people overestimate the riskiness of air travel because plane crashes are vivid and memorable. But if that's irrational, how much more irrational is it to believe that someone rose from the dead because one old book says so? Economists who study religion know enough about irrationality to send Kahneman, Tversky, and Thaler back to the minors. But presumably out of respect for religion they refuse to swing their bats.


What would economists learn if they started paying attention to the doctrinal side of religion? Now is my time for shameless self-promotion. In a series of papers on what I call "rational irrationality," I try to handle the deep objection that Larry sidesteps. I defend a rational choice theory of irrational belief. The gist of my theory is that people persistently hold wildly irrational religious beliefs because the material cost is usually very low. In terms of daily life, what difference does it make if the earth is 6000 years old or 6 billion? So it's not surprising how readily people shut their eyes to the geological evidence. In contrast, when the cost of irrationality is high, believers conveniently forget the teachings of their religion. Lots of religions promise paradise to martyrs, but adherents eager to die for their beliefs are one-in-a-million.


Is religion rational? In an important sense, NO. The doctrines of every religion are at best extremely improbable, but adherents are still very certain about them. Religious beliefs and standard economic models don't fit together. However, rather than ignoring or denying this incompatibility, economists should deal with it. If I'm right, it's not hard. Yes, religious beliefs are irrational, but they are so divorced from reality that they are rarely costly. When they do become costly, a few fanatics lay down their lives, but the overwhelming majority of the faithful open their eyes and face the fact that it's crazy to bet your life on fairy tales.