In the article described the psychological bases of the P-syllogism: Piaget's theory of the development of intellectual operations and theory of early cognitive development. On material of researches within cultural-historical approach was shown the possibilities of interpretation of empirical data, proceeding from the assumption of existence of two universally true and irreducible types of the apodictically evidence. The literature data can be interpreted as a divergence of physical and social representations. Physical representations characterize the sphere of reality about which is a researcher's task. Social representations characterize understanding of researcher's assessment of the answer by the probationers. Divergence of physical representations of mental healthy and adaptive probationers can be considered insignificant. Divergence of probationers answers are defined by orientation of probationers culture to the S-syllogism or the P-syllogism. Draw a conclusion from the assumption of the validity of the P-syllogism. In literature was described not ideas of probationers about reality (physical representations), but cultural norms of the reasoning’s, clear, i.e. "correct" from the point of view of representatives of the corresponding culture (social representation). Given are two version of the P-syllogism. in the P-syllogism is psychologically important the restriction of a possibility of evaluative judgment. On the example of decision making about vaccination finded possibility of the productive interaction between partners.