Zhuangzi and Huizi were strolling along the bridge over the Hao River.
Zhuangzi said, "the minnows swim about so freely, following the openings wherever they take them.
Such is the happiness of fish"
Huizi said, "You are not a fish, so whence do you know the happiness of fish?"
Zhuangzi said, "You are not I, so whence do you know I don't know the happiness of fish?
- Zhuangzi : Essential Writings, translated by B. Zyporyn