*Psychology*.--Since the mind grows and develops, it comes under the class of things which have a "source of motion internal to themselves," and psychology is therefore, for Aristotle, a branch of Physics. To understand his treatment of psychological questions we need bear two things in mind. (1) _Psyche_ or "soul" means in Greek more than "consciousness" does to us. Consciousness is a relatively late and highly developed manifestation of the principle which the Greeks call "soul." That principle shows itself not merely in consciousness but in the whole process of nutrition and growth and the adaptation of motor response to an external situation. Thus consciousness is a more secondary feature of the "soul" in Greek philosophy than in most modern thought, which has never ceased to be affected by Descartes’ selection of "thought" as the special characteristic of psychical life. In common language the word _psyche_ is constantly used where we should say "life" rather than "soul," and in Greek philosophy a work "on the _Psyche_" means what we should call one on "the principle of life." (2) It is a consequence of this way of thinking of the "soul" that the process of bodily and mental development is regarded by Aristotle as one single continuous process. The growth of a man’s intellect and character by which he becomes a thinker and a citizen is a continuation of the process by which his body is conceived and born and passes into physical manhood. This comes out in the words of the definition of the soul. "The soul is the first entelechy (or actual realisation) of a natural organic body." What this means is that the soul stands to the living body as all form realised in matter does to the matter of which it is the form, or that the soul is the "form" of the body. What the "organic body" is to the embryo out of which it has grown, that soul is to the body itself. As the embryo grows into the actual living body, so the living body grows into a body exhibiting the actual directing presence of mind. Aristotle illustrates the relation by the remark that if the whole body was one vast eye, seeing would be its soul. As the eye is a tool for seeing with, but a living tool which is part of ourselves, so the body is a like tool or instrument for living with. Hence we may say of the soul that it is the "end" of the body, the activity to which the body is instrumental, as seeing is the "end" to which the eye is instrumental. But we must note that the soul is called only the "first" or initial "entelechy" of the body. The reason is that the mere presence of the soul does not guarantee the full living of the life to which our body is but the instrument. If we are to _live_ in the fullest sense of the word, we must not merely "have" a soul; we "have" it even in sleep, in ignorance, in folly. The soul itself needs further to be educated and trained in intelligence and character, and to