The honeyed trope goes as follows:
Once, the celebrated Chinese philosopher Zhuangzi dreamt in a silvered dream that he was a butterfly. He floated into the wind and drifted with it. He beat his wings and fought against it. He settled on a multitude of sweet flowers and, putting forth his questing proboscis, was rewarded with their nectar. Drunk on the soma of the flowers, he rested...
...and awoke, Zhuangzi, the celebrated philosopher. He rubbed his eyes, scratched his head. Between his fingers he tested the tensility of his silken robe, the polish on the wooden floor, the alarming shortness of his tongue. He stepped out of his chamber and into the pavilion. At the heart of the gravel and benches, drifting above the pond full of carp, was the plum tree. On its furthest branch, a butterfly rested, its wings shut like parentheses.
Built to Spill - Carry the Zero - 2006
From that day on, until the end of his long and celebrated life, Zhuangzi was unsure of his life, which seemed tenuous and predicated on mysteries. He was never sure whether he was Zhuangzi, who had dreamt that he was a butterfly, or whether he was a butterfly, who was resting on a branch, dreaming he was Zhuangzi.
If David Hume were to walk through his pavilion at dusk, the elegant, bewigged Scotsman, and to take a pinch of snuff below the drifting plum tree, it could pass that Zhuangzi would motion him aside, and call him to the corner.
"Beware, Mr Hume", he might say, since all these things are possible, "that you do not disturb the butterfly."
Hume, frowning at the inscrutable mores of the orientals, might reply, "Why, pray, must we so be so solicitous of the convenience of this single butterfly?"
"It is entirely possible, Sir, that if this butterfly were to awake, we would disappear."
David Hume, who ideally would have preferred to have consented to such an arrangement, might dispute it thus:
"Preposterous, Sir! Surely this is impossible, for your mind is capable of conceiving of such a thing as a butterfly, whereas no part of the butterfly could conceive of you and I."
Zhuangzi peered at him closely. "Forgive me. You must be very wise indeed, Sir, to know so intimately the dreams of butterflies".