The physiological sketch given by Statius in the twenty-fifth canto, introduced to account for the spiritual body, is in logical order an introduction to Dante’s ethics and psychology; and is remarkable both in its agreement with Aristotle and its divergence from him. The occasion for it is found in a question raised by Dante, and suggested to him by the appearance of the shades in the circle which they have just left: namely, how beings who have no need to go through the ordinary process of nutrition, can feel the desire for food (as Forese has explained that they do) and grow lean through the deprivation of it. In order to solve this difficulty, Statius sketches briefly the stages of the development of the human being, from his first conception until he has an independent existence, showing how the embryo progresses first to vegetative then to animal life, and how finally, when the brain is complete (this being the last stage in the organisation), the “First Mover” breathes the human soul into the frame. The soul, having thus an independent existence, when the frame decays sets itself loose therefrom, taking with it the senses and passions, as well as the mental faculties of memory, understanding, and will. The latter are still in full activity, but the former have only a potential existence until such time as the soul has found its place in the other world. Then it takes to itself a bodily shape, formed out of the surrounding air (as a flame is formed by the fire), and equips it with organs of sense; and thenceforward this shape is adapted to express all the natural emotions and desires, including of course those of hunger and thirst. This remarkable exposition is based on Aristotle’s theory of the generation of the body, and the introduction into it of the soul; but there is an important difference. The Greek philosopher, though his language is not very explicit, has apparently no idea of any survival of the personal identity after death. At all events, so he was interpreted by Averroes and later by Aquinas. With him the source of all movement is the father, from whom only (though here again Aristotle is not quite clear) comes the gift of a soul. Dante, on the contrary, refers these back to the Prime Mover, namely God, and conceives a special creative act as performed on behalf of every human being that is brought into the world. As will be easily seen, this conception is the necessary complement to Dante’s system of ethics, based on individual free-will, and postulating a newly-created soul, fresh from the Maker’s hand; a _tabula rasa_, with no attributes save the natural propension towards that which gives it pleasure.