A set-theoretical and phenomenological case study of the concept of the "value" in K. Marx's "Capital" is sketchily presented. The intent is to go beyond the traditional concept of concepts and concept formation that has been adopted in the long history of psychological concept formation studies. The "value" concept is set-theoretically formulated as the set of sections of a relation, and is phenomenologically explicated as the sedimentation of the determinations by the external social horizon. With this case study, these two formulations, the author believes, are shown to go beyond the traditional concept: "Disregarding the particulars and extracting the common features" and/or "common response to dissimilar stimuli". Thus, the article attempts to draw the attention of fellow psychologists to the relevance of both the Set theory and Husserlian Phenomenology to the psychological study of "real" concepts and concept formation.