Update

Apologies for dropping off the map there—turns out moving and starting a new job in the midst of a pandemic takes up some bandwidth!  

Now that I've found my feet a bit, I just wanted to post a few quick blog updates:

• What's next?
  • My "blog ideas" folder is overflowing, so expect a series of short, fun explorations of apparent biases in the coming months. 
  • We'll play with simple Bayesian models of why beliefs persist after corrections, in what sense rationalization is rational, how (standard, precise) Bayesians can be averse to ambiguity, and even (maybe) why being hungry and tired can (unfortunately!) make it rational to grade more harshly.  Stay tuned!
• What happened to rational polarization?
  • As followers of this blog will have noticed, the Reasonably Polarized series never really wrapped up. That's because there's a bunch more to say—about how evidential ambiguity can make "overconfidence" and motivated reasoning rational, how it can help explain why polarization is increasing, and even how it fits with the fact that both sides of our political disagreements think that the other side is irrational.  
  • But instead of focusing on the blog versions, I'm currently (finally!) focusing on writing up the academic paper. Once that's done, I'll revisit those topics here.
  • In the meantime, if you want to get a whirlwind tour of the most recent version of the argument for rational polarization, check out the recording of this recent presentation I gave (handout here).
• What am I going on about?
  • I get a lot of questions of the form, "You say evidence is 'ambiguous' when it warrants higher-order uncertainty, which we can model with higher-order probabilities. But does higher-order probability even make sense? (Or sometimes: didn't Leonard Savage show in the 50s that higher-order probability is confused?)"
  • Great question. It does. (And he didn't.) The fact that we can have probabilities about our probabilities is no more puzzling than the fact that we can know things about what we know, or believe things about what we believe. 
    • If you have a basic familiarity with modal logic, here's a short writeup that explains how to model and think about higher-order probability in a simple concrete case (the word-completion task).
    • If you want more in-depth explanation of how to think about such models, check out this paper or this handbook article.

​More coming soon!