True, but some sort of heuristic is necessary. Without a heuristic for guessing what would be important ahead of time, we wouldn't have paging on computers, an

True, but some sort of heuristic is necessary. Without a heuristic for guessing what would be important ahead of time, we wouldn't have paging on computers, and then where would we be? If the heuristic is right more often than not, at least it's useful.