The fingers are relatively independent of one another and have relative autonomy in their movements. But, on the other hand, they are inseparable (in France one says of two friends: "Ilssont unis comme deux doigts de la main") and receive their very sense only from their togetherness. They thus offer a highly pertinent model for social groups of individuals: the unity and peculiar co-efficacy among small subgroups of larger collectivities could not be symbolized more impressively.

Georg Simmel, The Sociology of Georg Simm…, loc. 4769