More generally: LW is about developing human rationality, but is it appropriate for questions about already solved aspects of rationality?

Most posts here are written by someone who understands an aspect of rationality, to explain it to those who don't. I see no reason not to ask questions in the open thread. I think they should be top-level posts only if you anticipate a productive discussion around them; most already-solved questions can be answered with a single comment and that would be that, so no need for a separate post.