Well, given my background I knew virtually no philosophy. So I have taught myself most of the philosophy I know by teaching it. If I wanted to learn about something, I would teach a course on it (keeping a couple of weeks ahead of the students). I have learned a lot of philosophy this way, and it’s been a blast.
That’s Graham Priest (CUNY) in the What Is It Like interview.
I’m curious how common it is for philosophy professors to learn a new subject by teaching it. It isn’t unusual to throw a few new works one might not have read yet onto a syllabus as a way of having an opportunity to read and discuss them, but that’s less ambitious than what I’m asking about, which is teaching a course you hadn’t before, on a subject you don’t know, in order to learn the subject.
Have you done this? What was the subject? How unfamiliar were you with it in advance? What level of course was it? And how did you figure out what to put on the syllabus?