This joke was told to me by an Irishman, late in the evening in a seedy pub in Edinburgh. For some reason, it raises all sorts of deep questions about language, Wittgenstein, the meaning of meaning: none of which I can articulate.
A group of cavemen are sitting around their fire. They're hungry. Just then, the hunter comes in, carrying a strange animal that nobody has seen before.
After they've roasted and eaten it, they fall to debating what to call this new-found creature. All sorts of suggestions are bandied around, until the hunter loses his patience and says:
"It's called a rabbit!"
The company mutter and consider this suggestion. Finally one of them breaks, and asks:
"So, why's it called a rabbit, then?"
The hunter raises his eyes and stares disdainfully at the questioner.
"Because it looks like a fucking rabbit!"