Reading and conversing upon a subject will never make a man master of it, without close and steady thinking, and a fair and full decision. And no man can make a fair and full decision upon any abstract or intricate point, until he has thoroughly examined it on all sides. Hence the importance of attending to but one subject at a time, and of not leaving it before we come to a satisfactory decision.
Also attributed to: Emmons
The point
Mastery of a subject requires focused, disciplined thinking on one topic at a time, not just reading and talk.
