The teacher had a life before he learnt the art he teaches. That life brought him to the art. It also taught him vital lessons which enabled him to excel at the art he now teaches. These lessons he probably will not be able to teach. He probably doesn't even know that he embodies them. And yet they are crucial for learning the art. This is the predicament of the good student. She must be able to look beyond the art and see what the teacher has from before, and try her best to catch it.