Yi Qiu was the finest Go player in the land.
If he were to teach two students, one would listen with rapt attention, fully absorbed in the lesson. The other, while seemingly listening, would be thinking instead: 'If a swan were to fly by, how could I shoot it down with my bow and arrow?' Although both learn from the same master, the latter's results would be far inferior.
Is this because he is less intelligent? Certainly not. It is simply because he does not dedicate his mind to the task.