 Although the reference here to parts or aspects of the soul is cursory, it is influenced by Aristotle’s theories in the de Anima. Fundamental to the human soul and to all living things, including plants, is nutrition and growth (415a20 ff). Next is sensation and locomotion; these functions are characteristic of animals (416b30 ff). Aristotle associates appetite and desire with this part of the soul (414b1–5). Thus we have a rough sketch of animal life: animals, moved by appetite for food, go toward the objects of desire, which are discerned by sensation. To these functions is added thought in the case of humans. Thought is both theoretical and practical (427a 15–20). The bulk of the de Anima is devoted to explaining the nutritive, sensory, and rational functions; Aristotle considers desire and appetite as the source of movement in other animals (432a15 ff), and these plus reason as its source in humans. In Nicomachean Ethics he focuses on the role that appetite and desire, together with reason, play in the moral drama of human life.