6 “Actuality in the First Sense” and the Question of Human Nature in Aristotle John Russon Introduction In Book II, Chapter 1, of On the Soul, Aristotle distinguishes two senses of entelecheia, “actuality,” in order to express his defnition of the soul. I will explore some of the logical and ontological parameters of this very powerful distinction. I will frst consider how the distinction accords with characteristics of reality with which we are naturally familiar in everyday life. I will then refect upon the metaphysical complexity inherent to this notion and especially relate this to the life of a natural organism. From here, I will turn to my real interest: the human soul. We will see that when applied to the human being, the distinction takes on a signifcantly diferent form. We will ultimately see that it is this metaphysical distinction between the two forms of actuality that gives rise to ethics as a dimension of human life. I. Te Metaphysics of Everyday Life It is central to Aristotle’s method to “account for the phenomenona” (apodōsein ta phainomena), that is, to begin from, and to hold his analyses answerable to, what is immediately apparent. 1 In keeping with this methodological commitment, Aristotle argues, in Physics, Book II, Chapter 1, that phusis is obvious (dēlon) and that such obviousness must be the starting point for thought. 2 Tere is a similar obviousness, it seems to me, that lies behind the defnition of soul that Aristotle gives in Book II, Chapter 1, of On the Soul. Aristotle defnes soul as “the frst actuality [entelecheia hē prōtē] of a natural body capable of life.” 3 Tis defnition relies on a distinction that Aristotle draws at a number of points between two senses of “actuality,” a distinction that makes an important metaphysical point and draws its force from familiar features of everyday life. 4 He writes as follows: Aristotle on Human Nature.indb 81 Aristotle on Human Nature.indb 81 29-11-2022 20:32:54 29-11-2022 20:32:54