Quite a few people have signed up for these updates recently. Welcome! And welcome back to all the long-term readers. These newsletters’ original intent was to replace the public lectures that I had stopped giving because of Covid. Locked up at home, I missed the forced reflection of a stage, a mic, and a smart audience. In practice, the updates have become a random collection of the things that matter to me at any given moment. This week, that topic is ‘radicalization.’