Montaigne met a man who had lived twelve years among cannibals
He listened carefully, then turned the word 'barbarian' around and aimed it at his own country.
Sometime in the 1560s, Michel de Montaigne sat down with a man who had spent more than a decade in Brazil among the Tupinambá. He had questions. The man described people who went to war naked, used no iron, and practiced ritual cannibalism — eating the bodies of slain enemies as an act of revenge.
Montaigne transcribed the description without flinching. Then he turned to his own culture.
The Tupinambá, he wrote in his Essays, ate their enemies after death. Europeans, by contrast, racked prisoners while still alive, burned heretics by slow fire, and did it all under the name of religion. Who, exactly, were the barbarians?
This was not a defense of cannibalism. It was a precision instrument aimed at the assumption that one's own customs are the natural standard for all others. Montaigne was among the first European writers to use the word relativism as something other than an accusation. Custom, he argued, is a tyrant: it persuades us that whatever we do is reasonable simply because we have always done it.
He was writing in the middle of the French Wars of Religion, while his neighbors slaughtered each other over doctrine. The cannibals, at least, were honest about their motives.
The essay — 'Of Cannibals,' from Book I — is still the cleanest introduction to what moral relativism actually means: not that anything goes, but that the judge needs examining as much as the accused.