For decades, Soviet psychologists were engaged in the search for the cell (unit) of the psyche. The idea to transfer the ‘goods’ (the classical cell of the political economy of Marxism) into the sphere of psychological constructions seemed tempting. During the subsequent critical review, each of these “cells” has never emerged as the sole creator of the mental. The paper proposes a different interpretation of the mental world: it is formed not by a single “cell” in its development, but by a complex, multi-stage, internally connected, but qualitatively specific system of categories that finds sources for the development and internal organization in nature and society. The categories were inentified that form pleiads and clusters in theoretical psychology, the “theory of theories”, in which psychology reflects itself. The pleiade of the categories of natural causality indicates phenomena that can be documented by objective methods, “from the outside” (biophysical data). The pleiade of protopsychological categories contains noumena (intelligible entities). A pleiade of basic psychological categories refers to phenomena that are available for introspection. The pleiade of metapsychological categories contains ideas (unity of the thought and the conceivable, self-fulfilling representations). The pleiade of extrapsychological categories are controversies (discretions that instigate a diverse reinterpretation of existence and the mutual criticism of ideas about it by different researchers). Each of the clusters of categories reflects a fundamental dimension of human existence. Such are substantiality (organism, being, subject, the I, personality); orientation (deficit, need, motive, value, ideal); activity (metabolism, reflex, action, оbject activity, freedom); cognitivity (signal, sensation, image, consciousness, mind); bias (selectivity, affectivity, experience, feeling, meaning); co-being (synergy, coexistence, interaction, communication, involvement); and reality (environment, field, situation, objectness, world). There are different logical mechanisms of the horizontal (pleiades) and vertical (clusters) integration of the categories inherent to the process of their theoretical synthesis, which reflects the logic of the phylo-, socio- and ontogenesis of human beings in their becoming and development.