 A certain type of hate-crime, for instance, might be usefully analyzed as constituted in part by a speech act. That may be useful for social science or law, whether or not we can say much about the nature of speech acts. In economics, general equilibrium models are often designed to represent sets of households (as opposed to individuals), endowments of resources, sets of firms, goods, and other entities such as bonds and governments (Mas-Colell et al. 1995: Ch. 19). In models like these, some ontological work is implicitly done, in their partial analysis of economic systems into components. It is also common in sociological theory to analyze social entities into other social parts (see section  5.3).