¹ I think it is clear that both Aristotle and Plato are committed to the inference pattern in some cases. Aristotle explains the truth of “Socrates is human” and “Socrates is pale,” for example, by claiming that humanity belongs to Socrates as something that is said of him, while pallor belongs to him as something that is in him. (Aristotle introduces the “said of” and “in” relationships at Categories 1a20ff. as the two ways in which predicates belong to underlying subjects.) Plato explains the statue's being beautiful and large by reference to its participation or sharing in Beauty Itself and The Large. Aristotle may use the inference in the case of the broadly functional distinction among kinds of souls.

² For this terminology, see Armstrong, D. M., Universals: An Opinionated Introduction (Boulder, CO: Westview Press, 1989), p. 38.Google Scholar

³ See Wedin, Michael, Aristotle's Theory of Substance (New York: Oxford University Press, 2000), p. 398Google Scholar. Similarly, Code and Moravcsik write: “Rather, [Aristotle's statements about the soul] attempt to characterize what it is that enables some elements of reality to have life in them. In the course of this Aristotle appeals to certain powers and definable structures. This is analogous to characterizing flexible materials in terms of various powers and structures that they need in order to be flexible” (Code, Alan and Moravcsik, Julius, “Explaining Various Forms of Living,” in Essays on Aristotle's De Anima, edited by Nussbaum, M. and Rorty, A. [New York: Oxford University Press, 1992], p. 133).Google Scholar

⁴ An earlier version of this article proceeded as a kind of criticism of Wedin's use of dual complexity. Written comments from Wedin clarified my position and helped me focus on the issue of substantial unity. This is not to say that Wedin accepts the argument as I now present it.

⁵ Rodriguez-Pereyra, Gonzalo, Resemblance Nominalism (New York: Oxford University Press, 2002), pp. 45–46.CrossRefGoogle Scholar

⁶ Shields, Christopher, “Simple Souls,” in Essays on Plato's Psychology, edited by Wagner, E. (Lanham, MD: Lexington Books, 2001), pp. 137–56.Google Scholar

⁷ Unless otherwise noted, translations of Aristotle are those of Irwin, Terence and Fine, Gail, Aristotle Selections (Indianapolis, IN: Hackett Publishing, 1995).Google Scholar

⁸ In giving the basic essence as a Special Unity a role to play in explaining the unity of the composite, I am aligning myself with what David Charles calls the “explanatory interpretation,” as opposed to the “dissolutionist.” According to the latter, the unity of the composite is taken as basic and then abstracted from to reach form as unity. I am attracted to many of the aspects of Charles's explanatory view, including especially the idea that the basic essence has an intrinsic telos that explains why the form/matter composite is as it is. See Charles, David, Aristotle on Meaning and Essence (New York: Oxford University Press, 2000), pp. 283–309.Google Scholar

⁹ Among the recent commentators are: Halper, Edward, One and Many in Aristotle's Metaphysics: The Central Books (Columbus, OH: Ohio State University Press, 1989), pp. 184–95Google Scholar; Harte, Verity, “Aristotle's Metaphysics H6: A Dialectic with Platonism,” Phronesis, 41 (1996): 276–304CrossRefGoogle Scholar; and Wedin, , Aristotle's Theory of Substance, p. 209.Google Scholar

¹⁰ Additionally, my view requires that basic essences be wholly without material. I have argued for this in detail in Butler, Travis and Rubenstein, Eric, “Aristotle on Nous of Simples,” Canadian Journal of Philosophy, 34 (2004): 327–54.CrossRefGoogle Scholar

¹¹ As argued by Fortenbaugh, W. W. in “Aristotle on Slaves and Women,” in Articles on Aristotle, edited by Barnes, J., Schofield, M., and Sorabji, R. (London: Duckworth Publishing, 1975), Vol. 2. pp. 135–41.Google Scholar

¹² Kraut, Richard, Aristotle: Political Philosophy (New York: Oxford University Press, 2002), p. 285.Google Scholar

¹³ See Irwin, T. H., Aristotle's First Principles (New York: Oxford University Press, 1988), pp. 414–16.Google Scholar

¹⁴ Something like this may be what Halper has in mind when he claims that an essence “lacks anything to make it many” (Halper, , One and Many in Aristotles's Metaphysics, p. 185Google Scholar). Similarly, David Charles claims that the basic essence is an incomposite that lacks a certain kind of internal structure (Aristotle on Meaning and Essence, p. 292Google Scholar). However, he later seems to doubt whether a strong simplicity doctrine is required by the theory of essence (ibid., p. 304).

¹⁵ My view of the regress here is consonant with Harte's claim that Aristotle sees a problem for the Platonist about the unity of concrete particulars that is parasitic on a problem about the unity of forms (“Aristotle's Metaphysics H6,” p. 301Google Scholar). I have also been helped on the regress by Halper (One and Many in Aristotle's Metaphysics, p. 186).Google Scholar

¹⁶ Armstrong, D. M., “Against ‘Ostrich Nominalism,’” in Properties, edited by Mellor, D. H. and Oliver, A. (New York: Oxford University Press, 1997), pp. 108–11.Google ScholarPubMed

¹⁷ Ibid., p. 108.

¹⁸ I do not think this view would render the basic essence indefinable, since (i) the basic essence can be thought of as the entity signified by the definiens of a genuine definition, and (ii) there may be logical relations among the definiens and other bits of formulae such as those that refer to other differentiae and the genus. These logical relations would mirror metaphysical relations that hold among the basic essence and other entities. I think something like this is intended by Halper, (One and Many in Aristotle's Metaphysics, pp. 196–97Google Scholar). Charles, David writes: “Thus, even if non-composite, the essence can be discovered by uncovering the specific differentiating entity which is explanatorily basic; for, one can come to know it by detecting its distinctive causal role” (Aristotle on Meaning and Essence, p. 293).Google Scholar

¹⁹ Reeve, C. D. C., Substantial Knowledge: Aristotle's Metaphysics (Indianapolis, IN: Hackett Publishing, 2000), pp. 161–63.Google Scholar

²⁰ Here I have been helped by Freudenthal, Gad's Aristotle's Theory of Material Substance (New York: Oxford University Press, 1993), p. 55.Google Scholar

²¹ A further benefit may be a more plausible explanation of Aristotle's claim that thinking about simples is contact and cannot be false (Metaphysics, 1051b23–1052a2). If a simple essence has structural complexity, it is not clear why it would be impossible to succeed in contacting it in thought while still going on to think falsely about it. On the other hand, if an object lacks all internal complexity, it seems more plausible to identify necessary conditions for thinking of it at all with sufficient conditions for thinking of it inerrantly.

²² Thanks to David Sedley and Michael Wedin for comments on a much earlier version. Special thanks to two anonymous referees for this journal.