The value of thinking in terms of levels of abstraction has been suggested by Gibson and Horvath (1983; Horvath and Gibson, 1984). Interested in the character of, and possibilities of change within, the capitalist mode of production, they have recommended the development of concepts at various levels of abstraction, and in a manner already prefigured by Marx. For example, Marx proposed a crucial distinction in levels of abstraction between transhistoric transhistoric categories (means of production, immediate producers, and so on) and the historic forms assumed by these (capital, wage labor) that are specific to a given mode of production. At a still lower level of abstraction there are particular social formations (for instance, the contemporary South African social formation), which are structures of social relations specific to particular times and particular geographical areas (at various scales). The contribution of Gibson and Horvath is to propose an intermediate level of abstraction between ‘mode of production’ and ‘social formation’, a level at which one can identify what they call sub-modes of production. Within capitalism they identify four sub-modes: transitional, competitive, monopoly, and global. Although one can quarrel with the details the essential character of their method is clear.