The Master was strolling with some of his disciples along the bank of a river.
He said, "See how the fish keep darting about wherever they please. That's what they really enjoy.
A stranger overhearing that remark said, "How do you know what fish enjoy? You're not a fish."
The disciples gasped at what they took for impudence. The Master smiled at what he recognized as a fearless spirit of inquiry.
He replied affably, "And you, my friend, how do you know I am not a fish? You are not I."
The disciples laughed, taking this to be a well-deserved rebuff. Only the stranger was struck by its depth.
All day he pondered it, then came to the monastery to say, "Maybe you are not as different from the fish as I thought. Or I from you."