Schopenhauer's parable about how humans seek closeness for warmth but are driven apart by each other's negative qualities, discovering politeness as the proper distance for coexistence.
"One cold winter's day, a number of porcupines huddled together quite closely in order through their mutual warmth to prevent themselves from being frozen. But they soon felt the effect of their quills on one another, which made them again move apart. Now when the need for warmth once more brought th"