Randall Collins explaining functionalism

"Functionalist Ritualism
The generation of anthropologists and sociologists who studied rituals in the middle decades of the twentieth century may largely be called functionalist ritualists, to indicate a divergence in the Durkheimian school. The subcognitivist model was submerged in the functionalist program, but it is also detachable from it.
The aim of the functionalist movement was to show that all of the institutional practices of a society fit together and contribute to the maintainance of its structures as a whole. This approach has subsequently been dismissed as static. Indeed it has become so fashionable to dismiss functionalism that it is worth reconstructing the intellectual motives that once generated enthusiasm for this method of analysis (the best source for this is Goody 1995). As amateur anthropologists and text-oriented classicists gave way to a profession of field researchers, a group of Malinowski's followers began to emphasize that field work should study one whole society at a time, and analyze all of its practices as working institutions in relation to each other. This was carried out especially by Evans-Pritchard and Meyer Fortes, who examined each of several of African tribes with an eye to how its economy, political structure, kinship system, religion, and other institutions all functioned as part of a mutually supporting system. No institution could be understood in isolation: all were adapted to each other, and piecemeal changes in one component were not possible without either unraveling the whole or setting in motion countervailing changes that would bring the system back into equilibrium. This functionalist program opened up a promising set of tasks for field researchers, and also served as a polemical contrast to the methods of the older generation of amateur or library-based anthropologists. What the functionalists rejected were historicist interpretations that took a particular item out of context in its society as currently functioning, and interpreted it instead as a "survival" giving evidence of some earlier period of history. Functionalists turned their backs on history in order to reject speculative historical explanations (since isolated cultural items must have a contemporary function) and to get on with the business of showing structure in operation. The functionalists were consciously systematic, aiming at a general theory of how societies operate; a systematic theory of interconnected structures took priority over a theory of how structures changed, since the latter could be constructed scientifically only on the basis of the former.4
The functionalist program was easiest to apply in isolated tribal societies, or at least what appeared to be isolated and self-contained societies. Its guiding image was a set of structures functioning together as a unit, and thus distinct from other such functioning units outside its boundaries. Later critics would attack this point as well, arguing that the functionalists were too taken with the metaphor of society as a self-reproducing organism, or alternately that they modeled tribal societies on the ideology of the Western nation-state as a self-standing identity. Later it would be argued that tribes, too, have histories, and that they not only change over time but are to a considerable degree constituted by their "foreign relations" of trade, cultural prestige, military geopolitics, and kinship alliances (Chase-Dunn and Hall 1997). Such difficulties came especially to the fore after the functionalist program was generalized into a program for all sociological science, and applied to complex modern societies. The lead here was taken by Talcott Parsons and Robert Merton.5 Functionalist theory became a systematic listing of the basic functions that any society needs to carry out; a model of change as the differentiation of structures specializing in those functions; and a study of the strains that occur when functions are not properly met, and of the responses that the system makes to restore equilibrium. Parsons added an emphasis upon a shared value system that orients each specific social system, together with sets of norms that provide blueprints implementing these values in actors' behavior. The functionalist program as grand theory became bogged down in debates from the 1940s through the 1960s over what is functional or dysfunctional, what determines which functional alternatives are implemented, as well as whether the functionalist outlook is conservative in that it casts stratification and inequality in a favorable light, while ignoring conflicting interests inside a society. Eventually the whole research program lost adherents. Some rejected it because of presumed ideological bias; others because it seemed impossible to make progress toward empirically demonstrable explanations of what actually happens under what conditions."