How updating works

Changing your mind is the smart move

To “update your priors” is Bayesian shorthand. You start with a belief and a sense of how sure you are (the prior). You meet new evidence. You end with a revised belief (the posterior).

Most of what you learned in school was right when you learned it. Some of it has since been overturned, redrawn or renamed. A few things were never true at all; we call those never-facts. Updating isn't losing an argument. It's what careful people do when the facts change.

P(A | B) = P(B | A) · P(A) / P(B)
posterior odds = prior odds × strength of the evidence

The drip

One update at a time, in your inbox

Pick a pace. Weekly sends one prior update every Monday. Monthly sends the month's four in one letter on the first. No news cycle, no hot takes, just what changed and how we know. This list is separate from the daily Daily Explainer email.