The Habermas' model of “rational reconstructions” represents the main thread of the surveys about the structures of the lifeworld (culture, society and personality) and their respective functions (cultural reproductions, social integrations and socialization). For this propose, the dialectics between “symbolic representation” of the structures subordinated to all worlds of life (internal relationships) and the “material reproduction” of the social systems in their complex (external relationships between social systems and environment) has to be considered. This model finds an application, above all, in the theory of the social evolution, starting from the reconstruction of the necessary conditions for a phylogenesis of the socio-cultural life forms (the “hominization”) until an analysis of the development of social formations, which Habermas subdivides into primitive, traditional, modern and contemporary.