What is a sense of humor? Surely not the ability to understand a joke. It comes rather from a residing feeling of one's own absurdity. It is the ability to understand a joke, and that the joke is on oneself.
We prefer to think that the absence of inverted commas guarantees the originality of a thought, whereas it may be merely that the utterer has forgotten its source.
Name me any liquid — except our own blood — that flows more intimately and incessantly through the labyrinth of symbols we have conceived to mark our status as human beings, from the rudest peasant festival to the mystery of the Eucharist.