This chapter, following Franz Brentano, defines intentionality as the essential feature of the psychological, and, following Immanuel Kant, an a priori temporal–spatial format. It is argued, against Kant, that the format can be placed in the extra-mental world by making it a corollary to the second law of thermodynamics. Living beings can only exist under this law if they are regularly sustained by an outside source of energy, food in the case of animals, and it is argued that the self-initiated locomotion toward this food brings the format of intentionality into existence. It is further shown how locomotion through the interspace between organism and goal passes through four distinct phases, each of which has been the focus of a major field of psychology.