  When turning to these individual faculties of the soul, Aristotle considers nutrition first, for two related reasons. The first is straightforward: psychology considers all animate entities, and the nutritive soul belongs to all naturally living things, since it is “the first and most common capacity of soul, in virtue of which life belongs to all living things” (De Anima ii 4, 415a24–25). The second is slightly more complex, being at root teleological. Given that the higher forms of soul presuppose nutrition, its explication is prior to them in the order of Aristotle’s exposition.