Clearly, the central argument of the opponents to marriage is that it is an institution whose purpose is to stabilize something that cannot be stabilized, to make something last that will not last. All are agreed that physical love is as natural an instinct as huger or thirst, but the permanence of love is not instinctive. If, as is the case with so many men, physical love must have change, then why the promise of a life's devotion?
Un Art de Vivre (The Art of Living) (1939) - The Art of Marriage