"Is Religion Rational?" debate: Caplan, Iannaccone do the department proud

Congratulations to Bryan Caplan and Larry Iannaccone on an outstanding debate event last night.  It was great to watch them discuss two incredibly touchy issues -- economics and religion -- intelligently, passionately, and publicly.  From my limited surveying of fellow attendees, I heard nothing but rave reviews, which I hereby echo.  What a credit it is to GMU that such an event could be held at all, that it could be greeted with large attendance and complete respect from the audience, and that professors of their caliber are given such free rein here. 

Okay, paean over.  Like any good discussant (are you ready for this weekend, Michael?), I do have criticisms to offer.

I found Caplan's use of Iannaccone's old papers to be ineffective and unnecessary.  "But you said X before" is not an argument for a position or against a position; rather, by claiming that the opponent is personally inconsistent, it verges on the ad hominem fallacy.  If someone is pathologically hypocritical, you shouldn't be debating them at all.  If they are not, and you are debating an actual issue, then it's a sign of weakness when you try to hold anyone to something they wrote 10 or 20 years prior.  People grow and their opinions evolve.  That should be encouraged, not used as ammunition.  Anyone who pretends never to have changed his mind is, well, pretending; anyone who never has changed his mind is a fool.

On the substance of the arguments, it's a tougher call.  On the appropriateness of studying religion with the formal tools of economics, I did not detect any serious opposition from either debater (nor, in my opinion, should there have been).  On the money question, I think Iannaccone's analogies -- e.g., comparing the faith necessary for belief in God to that necessary for belief in Australia -- fall down rather quickly.  Believers do not, and should not, apply the same evidentiary standards for evaluating the existence of a continent that they apply to the existence of God.   Caplan is correct that, were we to apply our "continental" evidentiary standard consistently, we would be very hard-pressed to believe that concrete stories from religious texts accurately represent historical events. 

However, the most fundamental premises of religion are not the veracity of concrete stories; rather, they are claims about the nature of reality.  Some of these claims are neither provable nor disprovable; for instance, when the concept of a supernatural being is defined generally, it is not a proposition that is illuminated by the application of logic.  I submit that to accept claims of this sort is neither rational nor irrational, but...I am going to make up a word...arational.  In other words, what distinguishes religion is not doctrine (as claimed by Caplan) but rather faith.  Iannaccone clearly understands this point, but he did not cite it explicitly (nor did he seek to contradict Caplan).  Perhaps, as this point may have eliminated the premise of the debate, mentioning it was ruled out of bounds via a collusive agreement?

In summary:  I prefer Iannaccone's style of argumentation.  On the substance, I'm sympathetic to what Caplan is trying to do.  I think the central issue was, possibly for good reason, left off the table.  And a great time was had by all.

UPDATE:  Caplan has blogged on the debate and set up a page with related resources.  (In the picture on that page, Caplan is on the left, Iannaccone on the right.)