As I read this it occured to me that this is actually a lot like functions and fields/variables in programming. A function could be compared to a question where the result/answer it returns can change every time it's called/asked based on the current state of the system. A field holds an answer that is only valid for a time. The field gets "old" when it's not actively updated, but the function keeps being "fresh" because it's evaluated every time. It also compares nicely to answers being fast as a cache and functions being slow because the answer to the question has to be evaluated every time. Maybe a cache invalidation system for our brain would help us unstuck from held beliefs. I don't know. Just a few thoughts.