Classical theories are defined by a tendency towards biological analogy and notions of social evolutionism:
Functionalist thought, from Comte onwards, has looked particularly towards biology as the science providing the closest and most compatible model for social science. Biology has been taken to provide a guide to conceptualizing the structure and the function of social systems and to analyzing processes of evolution via mechanisms of adaptation ... functionalism strongly emphasises the pre-eminence of the social world over its individual parts (i.e. its constituent actors, human subjects).
While one may regard functionalism as a logical extension of the organic analogies for societies presented by political philosophers such as Rousseau, sociology draws firmer attention to those institutions unique to industrialized capitalist society (or modernity). Functionalism also has an anthropological basis in the work of theorists such as Marcel Mauss, Bronisław Malinowski and Radcliffe-Brown. It is in Radcliffe-Brown's specific usage that the prefix 'structural' emerged. Radcliffe-Brown proposed that most stateless, "primitive" societies, lacking strong centralized institutions, are based on an association of corporate-descent groups. Structural functionalism also took on Malinowski's argument that the basic building block of society is the nuclear family, and that the clan is an outgrowth, not vice versa.
Émile Durkheim was concerned with the question of how certain societies maintain internal stability and survive over time. He proposed that such societies tend to be segmented, with equivalent parts held together by shared values, common symbols or, as his nephew Marcel Mauss held, systems of exchanges. Durkheim used the term mechanical solidarity to refer to these types of "social bonds, based on common sentiments and shared moral values, that are strong among members of pre-industrial societies". In modern, complex societies, members perform very different tasks, resulting in a strong interdependence. Based on the metaphor above of an organism in which many parts function together to sustain the whole, Durkheim argued that complex societies are held together by organic solidarity, i.e. "social bonds, based on specialization and interdependence, that are strong among members of industrial societies".
These views were upheld by Durkheim, who, following Auguste Comte, believed that society constitutes a separate "level" of reality, distinct from both biological and inorganic matter. Explanations of social phenomena had therefore to be constructed within this level, individuals being merely transient occupants of comparatively stable social roles. The central concern of structural functionalism is a continuation of the Durkheimian task of explaining the apparent stability and internal cohesion needed by societies to endure over time. Societies are seen as coherent, bounded and fundamentally relational constructs that function like organisms, with their various (or social institutions) working together in an unconscious, quasi-automatic fashion toward achieving an overall social equilibrium. All social and cultural phenomena are therefore seen as functional in the sense of working together, and are effectively deemed to have "lives" of their own. They are primarily analyzed in terms of this function. The individual is significant not in and of himself, but rather in terms of his status, his position in patterns of social relations, and the behaviours associated with his status. Therefore, the social structure is the network of statuses connected by associated roles.
It is simplistic to equate the perspective directly with political conservatism. The tendency to emphasize "cohesive systems", however, leads functionalist theories to be contrasted with "conflict theories" which instead emphasize social problems and inequalities.