Author considers cognitive assumptions of practical consciousness: social and natural objects is based. Author follows the "constructivist" program in social theory in its classic version which is represented by social phenomenology and phenomenological sociology of knowledge (A. Sch.tz, P. Berger, T. Luckmann). Author analyzes some latent axioms and presuppositions, "idealizations" and mechanisms of everyday consciousness which constitute individual social experience at the level of micro-interactions with the objects and the "others". This analysis also refers to the intellectual heritage of classical theory of knowledge (epistemological ideas of I. Kant, E. Husserl). Author considers the status of the Other in the elementary systems of social interaction; discusses the necessity to assume the relative constancy and uniformity of the objective world elements including the existence of an integral self-identical "I" (actor's personality). The organized process of social experience uninterruptedly operated by cognitive schemes of practical consciousness is considered as one of the main conditions of reproduction of coordinated routines which support social order and institutional structures of the society.