Caplan Gums Bullet
I often disagree with people who know more about a given topic than I do. … I reason, if I did immerse myself in the modern literature, it’s a lot more likely that I would arrive at a sophisticated version of my current view than that I would radically change my mind. … When I argue with people who are better-informed than I am … [I ask] "If I saw and read everything that you’ve seen and read, what would I conclude?" … Even though the disputants are not on a level playing field, that isn’t the real reason why they hold different views. …
I suspect that Robin Hanson will be disturbed by my heuristic. After all, its lets every person retain his view that his prior is "special." You could even call my method the Anti-Hansonian Heuristic, because it deliberately ignores the fact that lots of smart people persistently disagree with you. In response to Robin, though, I’d say that (a) it’s almost impossible to convince anyone that his prior isn’t special – and my heuristic improves the quality of beliefs despite this impasse; and (b) since my prior is special (laugh if you must!), this is a great heuristic for me to live by.
I’d like to say Bryan bites a bullet here, but alas he just gums it, as he doesn’t engage the hard questions: what exactly is his better-origin scenario/story, and what evidence supports that story over less-flattering stories? That is, how could Caplan tell the difference between a situation where his prior was good and mine bad, vs. a situation where his prior was bad and mine good? If he grants that a reasonable person, long before our births, would have thought these two situations equally likely, what later evidence could have convinced this reasonable person that Bryan’s prior turned out better?
Rather, I think the question suggests the expert evaluate how attached to his bias he is. Rationalization is highly powerful under a guiding ideology. Reasoning is subject to multiple levels of indirection. Is it true? Is it important? How does one deal with uncertainty? What does one value most? Economists are experts at self-justification.
His method is interesting. He's essentially asking experts if the disagreement he as a non-expert has with them exists between experts in their field. This is a good heuristic, I think, and will often get to the meat of a disagreement while avoiding a lot of argument. I think by saying "my prior is special" he's merely embracing the inevitability of this bias and using it toward his methodological end, rather than claiming some special reason for his prior to be special.