We learn by example and by direct experience because there are real limits to the adequacy of verbal instruction.
It is those who are successful, in other words, who are most likely to be given the kinds of special opportunities that lead to further success. It’s the rich who get the biggest tax breaks. It’s the best students who get the best teaching and most attention. And it’s the biggest nine- and ten-year-olds who get the most coaching and practice. Success is the result of what sociologists like to call “accumulative advantage.
We spend a lot of time and effort trying to figure out who's going to be a good NFL quarterback, and we do a very bad job of it. We don't really know. And we also spend a lot of time trying to figure out who will be a good teacher, and we're really bad at that too. We don't know if someone is going to be a good teacher when they start teaching. So what should we do in those situations in which predictions are useless?