庄子与惠子游于濠梁之上,庄子曰:"银鱼出游从容,是鱼之乐也."惠子曰:"子非鱼,安知鱼之乐?"庄子曰:"子非我,安知我不知鱼之乐?"惠子曰:"我非子,固不知子矣.子固非鱼也,子之不知鱼之乐全矣."

Zhuangzi went out for pleasure with his friend Huizi on
the bridge over River Hao.
"How happily those little silver fish are swimming in
the water! (I wish I were a fish, too,)(加上这句为求生动)" said Zhuangzi.
At this Huizi said:"You aren't a fish, are you? How
can you know whether the fish are happy or not?"
"You aren't me," retorted the other, " how do you know
that I do not know the happiness of the fish?"
"Quite so," Huizi said, taking advantage of what the
other had said."It is true that I don't know your happiness
because I am not you, and for the same reason, you don't
know the happiness of the fish, because you are not a fish
.Isn't it clear enough?"
抛砖引玉,希望有更多更佳的译文.