Including external forms in the secret unifies the society’s total interest sphere

Evidence

The striking feature in the treatment of ritual is not only the rigor of its observance but, above all, the anxiousness with which it is guarded as a secret. Its disclosure appears to be as detrimental as that of the purposes and actions, or perhaps of the very existence, of the society. The teleological aspect of this is, probably, that the total action and interest sphere of the secret society becomes a well rounded unity only through inclusion, in the secret, of a whole complex of external forms. — Georg Simmel, The Sociology of Georg Simmel, 8697