The porcupine's right distance

In a famous fable, Schopenhauer describes porcupines that, numb with cold, huddle against one another, but whose quills force them apart; by trial and error they find the middle distance where one keeps warm without being pricked, and this distance, he says, is called politeness. The stance to cultivate: neither the fusion that wounds nor the solitude that freezes, but a warmth held at the right distance, all the wider the more one carries within oneself the means to keep oneself company.