CMT's fundamental philosophical principles come from diverse sketches of the body-mind problematic in western philosophy. Up until today Descartes' dualism (body and mind as separate entities) marks our thinking. The transition from philosophy to psychology through Ehrenfels, Koffka and Köhler, the Gestalt psychologists, brought about the change to a unifying concept. In the field of philosophy, the phenomenologist and existence philosopher Gabriel Marcel made a significant contribution to the overcoming of the body-mind split with his "Etre et avoir" theory. He arrives at the formulation "I have a body and am my body" ("corp que j` ai et corps que je suis") as does Maurice Merleau-Ponty in his "Phenomenology of Perception": "One's own body is in the world the way that a heart is in an organism: The body is what keeps the entire visible spectacle alive; it innerly nourishes and fills one with life and builds a single system with the spectacle."