If you're a director and you want to instruct an actor - you can either say to him 'Okay, now move your arm towards him like that', or you can say to him, 'Imagine who you are meant to be, and who he's meant to be. Now what do you do to him?'.
You see what I mean? It's like going a step further back in the composition process. So, instead of specifying the precise identity of something, you specify the little seed that will create an identity. You don't have to actually write it in its details.Brian Eno