I was trying to explain Bayesian probability to my eldest daughter Adela Luisa the other day. (She is only 13, but she is super smart.) In the process of explaining Bayes’ theorem to her, however, I realized that many areas of life seem to be largely immune from the process of Bayesian updating.

Consider politics, for example. Why are otherwise sensible and fair-minded people so dogmatic or closed-minded when it comes to their political beliefs? That is, why do so many people refuse to update their “political priors” no matter how much new evidence they receive from the media or other sources of information?

One possible answer is to compare political beliefs to “aesthetics” (or value judgments about art and beauty). If politics is just as subjective or personal as art and beauty, then it’s not clear how one would go about “updating” one’s political priors or one’s definition of beauty. This answer, however, poses a deeper and more difficult question: what is the relation between truth and beauty? Stated formally, are our personal preferences about art and beauty immune from Bayesian methods?