 This perspective does not diminish the ontological importance of structures, systems, and ideologies in history. It simply forces the historian, like the social scientist, to be attentive to the problem of articulating the relationship that exists between actors and structures. A system of norms, a property system, and a moral ideology of feudal loyalty can all be understood as being both objectively present at a time and place, and being ontologically dependent upon the mental frameworks, actions, and relationships of the individual actors who make up these systems. This problem has been thoroughly discussed in the philosophy of social science under the rubric of "ontological individualism" (Zahle and Collin, 2014). Higher-level social entities are indeed causally powerful in the social world; and they depend entirely for their causal powers on the characteristics of the individual actors who constitute them. This is the requirement of microfoundations: extended social structures and causes depend upon microfoundations at the level of the individuals who constitute them (Little 2017). In particular, we need to have some idea about how individuals have been brought to think and act in the ways required by the structures and ideologies in which they function as adults. On this approach, history is the result of the actions and thoughts of vast numbers of actors, and institutions, structures, and norms are likewise embodied in the actions and mental frameworks of historically situated individuals. Such an approach helps to inoculate us against the error of reification of historical structures, periods, or forces, in favor of a more disaggregated conception of multiple actors and shifting conditions of action. This is the conception to which we are drawn when we understand history along the lines proposed by Bloch.