For futures trading to be possible, the underlying asset has to be standardized, and that involves a version of Callon's "disentanglement" and "framing." The grain to which a futures contract makes reference may not even have been harvested yet, so a buyer cannot pick out a representative sack, slit it open, and judge the quality of the grain by letting it run through his or her fingers. "Five thousand bushels of Chicago No. 2 white winter wheat" has to be definable, even if it does not yet physically exist.

Donald MacKenzie, An Engine, Not a Camera, loc. 70