The turnout for the Iannaccone-Caplan Debate on Economics of Religion was excellent - about 300 people by my count. That's a striking illustration of interaction effects: as solo speakers either of us would have been lucky to draw 50 listeners!
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?
In case I didn't make it clear in the debate, Larry has done great work and deserves a lot of credit for opening up a fascinating new field of research. But I also think that economists who study religion are tip-toeing around some of the field's most important questions to avoid giving offense. And while there are many reasons why economics is the most successful social science, willingness to say what people don't want to hear is near the top.