Paul Seabright Responds!

My previous post review Paul Seabright’s new book The Divine Economy. Do go ahead and read that post first. Here I ask Paul some questions that came up doing my review and Paul has kindly agreed to respond. I hope you enjoy his detailed and insightful answers!

Mark: How did you land on the "platform" model of religion? Was it a well formed idea before you set out to write the book? Or did it emerge out of the process of researching and writing?

Paul: I work at the Toulouse School of Economics, where a lot of the theoretical research on platforms has been conducted by Jean Tirole, Jean-Charles Rochet, Bruno Jullien, Patrick Rey, Jacques Crémer and also by younger scholars such as Andrew Rhodes, Alex de Cornière and Yassine Lefouili. This is a fantastic environment in which to think about how platform relationships pervade our economic institutions. But the book has been a long time in the making, so the centrality of the platform model to my thinking has come about gradually. I was influenced by my empirical observations that the members of religious movements are simultaneously its greatest assets, an insight that is central to the notion of platforms. Seeing how often people would tend to find spouses among fellow members, for instance, made me realize that the congregations were also functioning as dating platforms. Even if it’s a key to the way the churches do this that you wouldn’t go to church to find a spouse whose only reason for going to church was to find a spouse.

Mark: A fascinating part of the book that I didn't explore in my review was your use of Robert Aumann's paper on agreeing to disagree to explore how much differences in beliefs matter for religious choice. Can you expand upon that argument?

Paul: I came across Aumann’s extraordinary theorem while working on my PhD many years ago. It takes two Bayesian decision makers who share a common prior about some event and who then observe private information, before sharing their posterior probabilities of that event. He shows that if their posterior probabilities are common knowledge they cannot diverge! In other words, two rational decision makers cannot “agree to disagree” about the truth of some proposition unless they have divergent priors (which raises the question where those divergent priors come from, since they cannot be the product of ...