Abstract: Modern capitalism, argued Mort Horwitz in the Transformation of American Law, 1780-1860, arrived with a new approach to contract. The claim was one of the most controversial that Horwitz made-and he made quite a few. I want to pick it up and push it from an angle that Horwitz never intended, although I like to think that he might endorse it. In honor of Horwitz, I will suggest that capitalism, so commonly identified with "commodification," came about precisely when society moved beyond commodification and into a world made possible by new forms of liquidity. Those forms of liquidity, the social relationships that they engendered, and the distribution of wealth that they supported were distinctively governed by a new approach to contract-an approach to contract that, with its sanctification of the ex ante terms of a promise for value, was very like the one that Horwitz flagged as the modern turn in his book.