Jennifer Roback Morse, in the same essay in The Meaning of Marriage that I wrote about yesterday, goes through the argument that marriage is a contract. She makes the point that contracts are most suitable for short-term and arms-length relations.
The sexual revolution, she says, has had some disastrous consequences for marriages because it changed the theory of sexual contracts. Under a marriage theory, sex is reserved for the most permanent, most intimate relations. Under the sexual revolution theory, by contrast, sex became a want best satisfied on the spot market.
The most intriguing point she makes, I think, is that for the most intimate and long term economic relations, the market finds that even long-term contracts are not enough. For permanent economic relations, the market invented the "firm."
Marriage is not a short-term contract for sex. It is not even a long-term contract for childrearing and companionship. A marriage is a firm, the most permanent, multi-faceted firm possible. In an ordinary firm or partnership, if they can no longer provide their distinctive good or service profitably, they dissolve. In a marriage, though, if the original product no longer works, they keep the firm and change what the firm produces.
Marriage is the firmest firm.