It seems to me like a reasonable generalization of the part where experts don't talk authoritatively about things outside their fields. You have degrees in CS and Philosophy, but I doubt you'd write about as related to your field as CPU manufacture, much less completely unrelated fields like aircraft design or particle physics. Staying out of shakespeare, political science, art history, and archaeology is just a broader extension of the same principle. In the reverse direction, if you know nothing about statistics, using statistics in your reasoning is probably a bad idea, and if someone brings in statistics you should pull in someone that knows how to do statistics so you're not making a decision that you don't understand. "Staying out of things you're not qualified to talk about" could prevent a lot of problems.