P.D. Ouspensky
Author: P.D. Ouspensky
Publisher: Vintage (1971)

You hear something which has a right place in the system, and if you can put it where it belongs, you cannot forget it and it will remain there; but if you just remember what was said without putting it into its right place, it is quite useless. Each small thing you hear you must try to understand, and to understand means to find the place where it belongs among other ideas. You must have a general idea of the system and everything new must have its place in it— then you will not forget, and every new observation you make will find its place. It is as though you have a drawing without details and observation fills in the details. If you have no drawing, the observation is lost