La plus difficile de nos vertus

The economic rationale for long term relationships in business (and elsewhere)

Writing to his mistress, Sophie Volland, in August 1759, the great encylopedist, man of letters and serial womaniser Denis Diderot congratulated himself (and presumably his chére Sophie) on the longevity of their relationship by writing

“La magie de la constance! La plus difficile et la plus rare de nos vertus.”

[The wonder of constancy! The rarest and mo…