Once Zhuangzi dreamt he was a butterfly, a butterfly flitting gaily about. He knew nothing about Zhuangzi. Then suddenly he awoke and he was at once solidly and unmistakably himself, Zhuangzi. But he didn’t know whether he was a man who dreamt he was a butterfly or was a butterfly dreaming he was a man. Surely there’s a difference between Zhuangzi and a butterfly. This is what we call the transformation of things.
—from the Zhuangzi, a Daoist text (authored by Master Zhuang)