Why should the law care about enforcing contracts? We tend to think of a contract as the legal embodiment of a moral obligation to keep a promise. When two parties enter into a transaction, they are obligated as moral beings to play out the transaction in the way that both parties expect. But this overlooks a broader understanding of the moral possibilities of the market. Just as Shakespeare's Shylock can stand on his contract with Antonio not because Antonio is bound by honor but because the enforcement of contracts is seen as important to maintaining a kind of social arrangement, today's...