200 dinars

Under Islamic law, a husband could divorce his wife but a wife could not divorce her husband. The wife in the story, having received a windfall due to the Vizier’s carelessness in promising her gold instead of silver–a dinar was worth about ten times as much as a dirhem–wants to get rid of her husband, still poor. She cannot divorce him. She can however make  being married to her sufficiently unpleasant to force him to divorce her. Even for the Vizier, enormously more wealthy and powerful, a matching donation to the husband is an easier solution than trying to force the wife to maintain her side of the implicit contract of her marriage.

The story, written and set in the Islamic world of a thousand years ago, reveals a problem with the market model of our system for allocating marriage partners. A man can try to persuade a woman to marry him by offering her especially favorable terms, promising to wash all the dishes and live near her friends and family instead of his, and similarly for the same situation with partners reversed. But once they are married many of the terms of the contract cannot be enforced even if the authorities want to enforce them, because performance cannot be observed from outside the marriage. No wife, so far as I know, has ever gotten more favorable terms in a divorce settlement by showing that her husband was less deferential to her preferences than he had promised. No husband, so far as I know, has ever gotten more favorable terms by arguing to the court that his wife deliberately cooked, or made love, badly. There is still the possibility of enforcing the terms by the threat to leave the marriage, at least in a society with reasonably easy divorce. But that threat becomes less believable as the marriage partners acquire joint assets, most obviously children, best enjoyed jointly.

Marriage in our system is some mix of the market with implicit prices earlier described and a straight sorting algorithm where the only price either partner can offer the other is himself, the bundle of characteristics that make him a desirable match—the most desirable woman marrying the most eligible man and so on down the list.[1] Plus, perhaps, a certain random element:

“Women have simple tastes. They get pleasure out of the conversation of children in arms and men in love.” (H.L. Mencken)

The dating/sex/marriage market suffers from a number of problems, in addition to unenforceable contracts, that help explain why there are so many people who would like a lover or spouse and don’t have one and why so much time and energy go into attempts to solve that problem. Most exchanges let us separate

Another thing I found interesting about the story was what it revealed about wealth inequality in a past society. A windfall of two hundred dinars is enough to make a poor woman feel rich enough to want to get rid of her poor husband. In another story in the same book, a prince casually asks his vizier to find him five hundred thousand dinar for a project. In a third story, a wealthy man, being treated badly by the vizier currently in power, threatens to bribe the Caliph to replace that vizier with another. The bribe he plans to offer is two million dinar, ten thousand times the amount that, for the poor woman in the first story, was enough to change poverty to wealth.

[1] For a more detailed account of the two models, see Chapter 21 of my webbed Price Theory.