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AVERROES AND AQUINAS ON ARISTOTLE'S CRITERION OF SUBSTANTIALITY

Published online by Cambridge University Press:  23 September 2009

GABRIELE GALLUZZO
Affiliation:
Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa, Italy Email: g.galluzzo@sns.it

Abstract

The paper analyses Averroes's and Aquinas's different reconstructions of Aristotle's ontology in the central books of the Metaphysics. The main claim the paper argues for is that Averroes endorses an explanatory criterion of substantiality, while Aquinas favours an independent existence criterion. The result of these different choices is that the Arabic commentator believes that the forms of sensible objects are more substances than the objects of which they are the forms, while the Dominican Master sticks to the traditional picture that sensible objects hold some kind of priority over their ontological constituents in general and over form in particular. For Averroes, therefore, the central books of the Metaphysics mark a major departure from the Categories ontology, where particular sensible objects are regarded as fundamental entities and so primary substances. On Aquinas's reconstruction, by contrast, sensible objects are still thought of in the Metaphysics as primary substances in spite of their being analysable into matter and form.

Résumé

Le présent article étudie les différentes reconstructions, proposées respectivement par Averroès et Saint Thomas d'Aquin, de l'ontologie aristotélicienne des livres centraux de la Métaphysique. Sa thèse principale consiste à soutenir qu'Averroès voit dans la substantialité un critère explicatif, tandis que Saint Thomas l'associe au fait d'avoir une existence indépendante. Le résultat de ces choix différents est que pour le commentateur arabe, les formes des objets sensibles sont davantage substance que les objets dont elles sont les formes, tandis que le maître dominicain en reste à la position traditionnelle selon laquelle les objets sensibles ont une certaine primauté sur leurs constituants ontologiques en général et sur leur forme en particulier. Pour Averroès, par conséquent, les livres centraux de la Métaphysique constituent une rupture majeure par rapport à l'ontologie des Catégories, oeuvre qui tient les objets sensibles particuliers pour les entités fondamentales, donc pour les substances primaires. Selon la reconstruction de Saint Thomas, en revanche, les objets sensibles sont considérés comme des substances premières jusque dans la Métaphysique, en dépit du fait qu'ils peuvent être analysés en matière et forme.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2009

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References

1 Cf. Aristotle, Cat., 5, 2a11–14.

2 Cf. Aristotle, Cat., 5, 2b5–6c.

3 Cf. Aristotle, Met., Z 7, 1032b1–2; 10, 1037a28.

4 For a critical reconstruction of the literature concerning Metaphysics Z I take the liberty of referring to: G. Galluzzo – M. Mariani, Aristotle's Metaphysics Book Z: The Contemporary Debate, Scuola Normale Superiore (Pisa, 2006).

5 In so far as the interpretation of Met. Z is concerned, I would like to point to the following general aspects where Averroes's influence on Aquinas is particularly evident: (i) the understanding of Met. Z's logical character and the consequent claim that the whole of Book Z is logical; (ii) the individuation of a robust anti-Platonic line within Z's argument, which runs all through the book and affects in particular the interpretation of Z 6, Z 7–9 and Z 13–16; (iii) the interpretation of the notion of subject (for this aspect, see below, pp. 172–4 and 180–2).

6 Cf. Aristotle, Met., Z 2, 1028b8–13. But see also: Met., Z 3, 1029a2–3; 11, 1037a28; H 1, 1042a24–31; 3, 1043a29–31; 1037a29–21.

7 Ibid., Z 7, 1032b1–2; 10, 1037a28.

8 See for instance: Aristotle, Met., Z 7, 1032b1–2; 10, 1035b15–17; 1037a29–31; 1041b8–9.

9 Cf. Aristotle, Met., Z 7, 1032b1–2; 10, 1035b15–17; 1035b32; 17, 1041a28.

10 This interpretation, which is strongly defended among others by Frede and Patzig (see in particular: M. Frede – G. Patzig, Aristoteles ‘Metaphysik Z’. Text, Übersetzung und Kommentar, 2 vols. [München, 1988], vol. II, pp. 166–220; M. Frede, The Definition of Sensible Substances in Metaphysics Z, in D. Devereux – P. Pellegrin [eds.], Biologie, logique et métaphysique chez Aristote [Paris, 1990], pp. 113–29), seems to reflect the main argumentative line in Met. Z 10–12. See, however, Met. Z 10, 1035a22–b1; 11, 1036b21–32; H 2, 1043a14–28; 3, 1043b23–32 as examples of texts which seem to suggest that matter should not be left out of the definition of sensible substances (for this interpretation see for instance: D. Morrison, Some Remarks on Definition in Metaphysics Z, in Devereux – Pellegrin [eds.], Biologie, logique, pp. 131–44; M.J. Loux, Primary Ousia. An Essay on Aristotle's Metaphysics Z and H [Ithaca / London, 1991]). That matter is part of the essence and definition of sensible substances is Aristotle's standard doctrine in his physical works (see for instance: Phys., B 2, 193b22–194a12; De An., A 1, 403a29–b19) and in general in texts where he describes sensible substances as physical objects (Met., E 1, 1025b28–1026a6). For a general reconstruction of the debate over Aristotle's doctrine of essence and definition see: Galluzzo – Mariani, Aristotle's Metaphysics, pp. 135–65.

11 For two particularly striking examples of incompatibilism see: D. Graham, Aristotle's Two Systems (Oxford, 1988); Frede – Patzig, Aristoteles ‘Metaphysik Z’.

12 For an explicit endorsement of compatibilism see: M.V. Wedin, Aristotle's Theory of Substance (Oxford, 2000); M. Burnyeat, A Map of Metaphysics Zeta (Pittsburgh, 2001). Of course, many scholars take positions which can be described as intermediate between the two extreme options. A good example of this attitude is: Loux, Primary Ousia.

13 Cf. Aristotle, Cat., 5, 2a11–2b6c.

14 Ibid., 2, 1a20–b9.

15 Cf. Aristotle, Met., Z 3, 1029a10; a18–19; a27.

16 Ibid., 1029a10–30.

17 The general sense as well as the details of the stripping-away argument have been at the centre of a heated debate. Some scholars maintain that the argument is a genuinely Aristotelian one (e.g. Loux, Primary Ousia, pp. 49–71), whilst some others take it as non-Aristotelian (e.g. Frede – Patzig, Aristoteles ‘Metaphysik Z’, pp. 33–56). In the former hypothesis, the argument represents a correct application of the subject criterion, whilst in the latter it is simply the result of a misapplication of the idea of subjecthood. From a different perspective, the question has been raised whether the argument is supposed to lead us to the discovery of a mind-independent entity as opposed to a merely intentional one (see on this issue: M. Schofield, “Metaph. Z 3: Some suggestions”, Phronesis, 17 [1972]: 97–101; D. Stahl, “Stripped away: some contemporary obscurities surrounding Met. Z 3”, Phronesis, 26 [1981]: 177–88). Finally, it is not clear whether the matter Aristotle talks about in the course of the ontological “striptease” is prime matter or ordinary matter (R. Dancy, “On some of Aristotle's second thoughts about substances”, Philosophical Review, 87 [1978]: 372–413). In my reconstruction, I stayed neutral on whether the argument is Aristotelian or not, for nothing of what I wish to say depends on taking one option or the other. I do believe, by contrast, that the stripping-away argument leads to the discovery of a mind-independent and ontologically significant entity, i.e. matter. Moreover, my opinion is that the argument does not concern prime matter but rather the ordinary stuff of which material objects are said to be made, but I am not going to argue in favour of this view in this paper.

18 Cf. Aristotle, Met., Z 3, 1029a23–24. The matter-form predication is a rather obscure piece of doctrine of which scholars have tried to make sense in different ways. See for instance: V.C. Chappell, “Aristotle on matter”, Journal of Philosophy, 70 (1973): 679–96; Dancy, “On some of Aristotle's second thoughts”; J. Brunschwig, “Forme, prédicat de la matière”, inP. Aubenque (ed.), Études sur la Métaphysique d'Aristote. Actes du VI Symposium Aristotelicum (Paris, 1979), pp. 131–58; C. Page, “Predicating forms of matter in Aristotle's Metaphysics”, Review of Metaphysics, 39 (1985): 57–82; F.A. Lewis, Substance and Predication in Aristotle (Cambridge / New York / Port Chester / Melbourne / Sidney, 1991); Loux, Primary Ousia, pp. 147–96. In my opinion, Lewis and Loux set up the problem correctly by asking whether form is accidentally or essentially predicated of matter and go for the first alternative – a view I tend to agree with. Be that as it may, it is clear that the matter-form predication is first of all a special kind of ontological relation tying up matter and form. Therefore, we should not necessarily look out for linguistic formulae expressing such a relation, even though the possibility cannot be ruled out that there might be some.

19 Cf. Aristotle, Met., Z 3, 1029a2; H 1, 1042a26–29; 2, 1042b9; Θ 7, 1049a36.

20 Ibid., Z 3, 1029a27–30.

21 Ibid., H 1, 1042a29–31.

22 On Aristotle's notion of χωριστóν in general see: D. Morrison, “Separation in Aristotle's Metaphysics”, Oxford Studies in Ancient Philosophy, 3 (1985): 125–57; G. Fine, “Separation: a reply to Morrison”, Oxford Studies in Ancient Philosophy, 3 (1985): 159–65; D. Morrison, “Separation: a reply to Fine”, Oxford Studies in Ancient Philosophy, 3 (1985): 167–73.

23 Cf. Aristotle, Met., H 1, 1042a30–31.

24 Ibid., 1042a29.

25 This view is convincingly defended by M.L. Gill, Aristotle on Substance. The Paradox of Unity (Princeton, 1989), pp. 31–8.

26 Cf. Aristotle, Cat., 5, 3b10–23. For the opposition between τóδε τι and ποιόν/τοιόνδε see: J. Kung, “Aristotle on thises, suches and the third man argument”, Phronesis, 26 (1981): 207–47.

27 As is known, the so-called “theory of particular forms” has been strongly defended in recent times by M. Frede (see for instance: M. Frede, “Individuals in Aristotle”, in Id., Essays in Ancient Philosophy (Oxford, 1987), pp. 49–71; M. Frede, “Substance in Aristotle's Metaphysics”, in Id., Essays, pp. 72–80; Frede – Patzig, Aristoteles ‘Metaphysik Z’, esp. vol. I, pp. 48–57). For the indication of a very reasonable sense in which forms can be thought of as non-particular, see: A. Code, “The aporematic approach to primary being in Metaphysics Z”, in J. Pelletier – J. King-Farlow (eds.), New Essays on Aristotle, Canadian Journal of Philosophy, suppl. X (1984): 1–20. The intricate debate over the status of Aristotle's forms is reconstructed in: Galluzzo – Mariani, Aristotle's Metaphysics, pp. 135–211.

28 Cf. Aristotle, Met., Z 17, 1041a9–10.

29 Ibid., 1041a27–30.

30 Ibid., 1041b7–9.

31 Ibid., 1041a32–b9.

32 Ibid., 1041a6–10.

33 Cf. Averrois Cordubensis In Aristotelis Metaphysicorum Libros Commentarium, Lib. VII, t.c. 44, in Aristotelis Opera cum Averrois Commentariis, apud Junctas, Venetiis 1562–1574 (repr. Minerva, Frankfurt a. M. 1962), vol. VIII, f. 197r C. See also: In Met. VII, t.c. 5, f. 156r E ff., where Averroes presents the Ancients' philosophical investigation as an enquiry into the causes of particular sensible substances.

34 Cf. Averroes, In Met. VII, t.c. 5, f. 156r A.

35 For some useful considerations about whether Averroes is compatibilist or incompatibilist, see: M. Di Giovanni, “Individuation by matter in Averroes' Metaphysics”, Documenti e studi sulla tradizione filosofica medievale, 18 (2007): 187–210. In the paper Di Giovanni also convincingly argues that for Averroes Aristotle's forms are not particular in the sense of the modern debate.

36 Cf. Averroes, In Met., VII, t.c. 5, f. 156r F–v G.

37 This principle is stated by Aristotle in Met., α 1, 993b24–25 and clearly approved by Averroes in the corresponding commentary (cf. In Met., II, t.c. 4, f. 30r A–B).

38 Cf. Averroes, In Met. VII, t.c. 3, f. 154r E–F. See also: t.c. 5, f. 155v M.

39 For an interesting discussion of this and some related issues from the point of view of contemporary philosophy, see: E.J. Lowe, The Possibility of Metaphysics (Oxford, 2001), esp. pp. 136–53.

40 For a contemporary supporter of the view that Aristotle endorses a “theory of particular accidents” see: J.L. Ackrill, Aristotle's Categories and De Interpretatione (Oxford, 1966). For a different view see: G.E.L. Owen, “Inherence”, Phronesis, 10 (1965): 97–105; Frede, “Individuals in Aristotle”.

41 This principle seems to be stated for instance in Averroes, In Met. VII, t.c. 8, f. 159r C: “illud, per quod substantia fit substantia, est substantia”. Averroes does not explicitly say that that in virtue of which a substance is a substance is more substance than the substance it explains. However, that this is the sense of his remark is clear from In Met. VII, t.c. 7, f. 158r A–B. See also: In Met. VII, t.c. 7, f. 157v L, where the principle is applied to the relation between particular substances and their ontological constituents.

42 Cf. Averroes, In Met. VII, t.c. 60, f. 208v G.

43 Ibid.

44 Ibid., t.c. 59, f. 207r A–B.

45 In the second part of Z 17 (1041b11–33) Aristotle argues for the view that the principle that keeps together and gives structure to the material parts of a sensible object, i.e. form, is different in nature from such material elements. When commenting on this claim (In Met. VII, t.c. 60, f. 209r B), Averroes observes that a sensible object is made of material elements plus substance, thereby identifying form with the substantial core of a sensible object and treating the material parts as somewhat non-substantial in character.

46 Cf. Aristotle, Met., Z 3, 1029b33–36.

47 Cf. Averroes, In Met. VII, t.c. 7, f. 157v K–L.

48 Ibid. Differently from modern interpreters, but also from Aquinas, Averroes takes “the universal” to refer to the most general kinds, whilst he interprets “the genus” as referring to the lowest kinds, presumably the species in the strict sense of the term.

49 Ibid., t.c. 7, f. 157v L.

50 Cf. Aristotle, Met., Z 3, 1029b36–37.

51 Cf. Averroes, In Met. VII, t.c. 7, f. 157v L and Aristotle, Cat., 2, 1b3–6; 5, 2a11–14.

52 Ibid., t.c. 7, f. 157v L.

53 Ibid., t.c. 8, f. 159v G.

54 Ibid., t.c. 8, ff. 158v L; 159r D; 159r F.

55 In Aristotle's text, the conclusion that matter is primary substance is rejected on the grounds that matter does not satisfy two important requirements for something to be regarded as a substance, namely being separable and being a τóδε τι. Unfortunately, the translation of the Greek Averroes could avail himself of obscures the sense of Aristotle's text. As a result, the Arabic commentor ends up having little to say about being separable and being a τóδε τι. He confines himself to remarking that the concepts that can be understood separately from other concepts, i.e. the predicates that enter into the definition of sensible substances, indicate that form and not matter qualifies as the substance of a sensible object (In Met. VII, t.c. 8, f. 159r F). Thus, Averroes's suggestion is that the substance of particular sensible objects can be discovered through an analysis of essence and definition and not through the notion of subject.

56 Cf. Averroes, In Met. VII, t.c. 8, f. 159r F – v G.

57 See in particular: Averroes, In Met. VII, t.c. 8, f. 159r F: “Sed impossibile est quod materia sola sit substantia”. See also: In Met. VII, t.c. 8, f. 159r D.

58 Cf. for instance: Averroes, In Met. VII, t.c. 11, f. 161r D–F. In the text, Averroes formulates a very general principle according to which in a proper definition the predicates figuring in the definiens must form an essential unity with, i.e. be of the same nature as, both one another and the definiendum. And only things that have a proper definition have also an essence in the strict sense of the term. In the course of Z 4–6's abstract discussion, Averroes refers to the things that have a proper definition and essence by the general term “substances”, but he already hints that by “substances” we should mainly understand “forms” (cf. Averroes, In Met. VII, t.c. 13, f. K–L).

59 Cf. Aristotle, Phys., B 2, 193b22–194a12; De An., A 1, 403a29–b19; Met., E 1, 1025b28–1026a6; Z 10, 1035a22–b1; 11, 1036b21–32; H 2, 1043a14–28; 3, 1043b23–32. For more details on this point see footnote 10 above.

60 This seems to be the contrast Aristotle wishes to draw in the famous passage about Socrates the Younger (Z 11, 1036b21–32). Unlike mathematical objects, material objects are necessarily made of sensible matter. What is not clear, however, is whether he intends to conclude from this remark that sensible matter should be also mentioned in the definition of sensible substances. For an argument against this conclusion see: Frede–Patzig, Aristoteles ‘Metaphysik Z’, esp. vol. II, pp. 211–13. Frede and Patzig argue that matter is not mentioned in the definition of sensible substances, but only implied by it. In other words, from the definition of sensible substances we should be able to infer that they are material objects, but this does not mean that their definition should explicitly mention matter. The distinction between mentioning and implying is congenial to Averroes's view, but I found in his commentary no decisive evidence that he explicitly draws it. On this problem, see: M. Di Giovanni, “Averroes on the doctrine of genus as matter”, Documenti e studi sulla tradizione filosofica medievale, 15 (2004): 255–85. On Averroes's overall understanding of Aristotle's notion of definition see: M. Di Giovanni, “La definizione delle sostanze sensibili nel Commento Grande (Tafsīr) di Averroè a Metafisica Z 10”, Documenti e studi sulla tradizione filosofica medievale, 14 (2003): 27–63; Id., Averroes on Substance, Phd Dissertation, Scuola Normale Superiore (Pisa, 2008), pp. 51–96 (esp. 75 ff.). Although I generally find myself in agreement with the line Di Giovanni takes, I suspect I insist more than he does on attributing to Averroes the view that matter should be left out of the definition of sensible substances.

61 Cf. Averroes, In Met. VII, t.c. 33, f. 184v G.

62 Here I cannot offer a thorough discussion of the textual evidence in favour of my view. However, my suggestion seems to be confirmed by Averroes's somewhat obscure remark at the beginning of t.c. 35 (In Met. VII, t.c. 35, f. 186r E–F; see also: t.c. 35, f. 186v K and M) concerning the two aforementioned kinds of definition. He says that, in the case of the definitions where matter appears, the definition of each part (of the thing) is not part of the definition of the whole, whilst in the case of the definitions where matter does not appear, the definition of each part of the thing is part of the definition of the whole. I think that the only way of making sense of Averroes's remark is to suppose that he is talking about two different formulae of the composite substance. The formula that mentions matter is a rough description of what a composite substance is. Therefore not all the parts of the thing which are mentioned in this formula are also parts of the true definition of the thing: material parts in fact are not parts of the true definition of the thing, which mentions only formal parts. The formula which does not mention matter, by contrast, is the true definition of what a composite substance is. In this case, therefore, all the parts of the thing which are mentioned in the formula are also parts of the true definition of the thing, because this second kind of formula mentions only formal parts. Admittedly, sometimes (In Met. VII, t.c. 33, f. 186v G–H; t.c. 35, f. 186v L). Averroes expresses himself as if the second kind of definition were the definition of form and not that of the composite. But this is perfectly natural because, as we shall see shortly, the true definition of a composite substance is in some sense the definition of its form. The difficulty with Averroes's remark in t.c. 35 stems from his using the term “definition” throughout the text to refer to both a formula in general and the true definition of the thing. A good paraphrasis of what Averroes means could probably be the following: in the case of the formulae where matter appears it is not true that each part (of the thing) is part of the true definition of the whole, whilst in the case of the formulae where matter does not appear each part of the thing is part of the true definition of the whole.

63 Cf. Averroes, In Met. VII, t.c. 33, f. 184r D and F.

64 By using the qualification “essentially” in the formula “a sensible object is essentially a certain kind of form” I want to avoid attributing to Averroes the view that there is no mind-independent distinction between a sensible object and its form and so a sensible object and its form are fully identical. On the contrary my view is that form is identical with the sensible object of which it is the form only from the point of view of essence, i.e. only when we consider what makes of a sensible object what it is. From the point of view of concrete existence, by contrast, a sensible object and its form are distinct, in that form is a constituent of the sensible object as much as the matter in which form exists. My view, therefore, also implies a mind-independent distinction between form and matter. For a particularly insightful discussion of the complex issue of the relation among form, matter and the composite of matter and form see: Di Giovanni, Averroes on Substance, pp. 51–96. Di Giovanni analyses at length the textual evidence in favour and against the view I present here. The issue is also brought to light by C. Cerami, De la philosophie seconde à la philosophie première: l'étude de la génération absolue chez Aristote et Averroès, Phd Dissertation, Scuola Normale Superiore (Pisa, 2007).

65 This point is explicitly stated in In Met. VII, t.c. 37, f. 189r C–D, where matter is described as that whose existence does not imply the existence of the thing, whilst form as that whose existence implies the existence of the thing. Averroes's point must be not that a sensible substance can exist without matter, but rather that form and not matter is what makes of a certain thing the kind of thing it is.

66 The principle is stated for instance also in Met., Z 3, 1029b3–12, but see also: Phys., A 1, 184a16–21; An. Post., A 2, 71b33–72a5.

67 Cf. Averroes, In Met. VII, t.c. 34, f. 184v M; In Met. VII, t.c. 37, f. 189r C.

68 S. Thomae Aquinatis In Duodecim Libros Metaphysicorum Expositio, Lib. VIII, lect. 3, ed. M.-R. Cathala – R. Spiazzi (Taurini / Romae, 1964), n. 1682.

69 Cf. Aquinas, Exp. Metaph., Proem.

70 A locus classicus for this distinction is: S. Thomae De Aquino De principiis naturae, c. 1, Opera Omnia, t. XLIII (Opuscula IV), Editori di S. Tommaso (Roma, 1976), pp. 42, ll. 42–123 (esp. ll. 42–58).

71 Cf. Aquinas, Exp. Metaph., Lib. VII, lect. 2, n. 1276.

72 Ibid., lect. 2, nn. 1281–1284.

73 Ibid., lect. 2, nn. 1278; 1281; 1284.

74 Ibid., lect. 2, nn. 1285–1290.

75 Ibid., lect. 2, n. 1291.

76 Ibid., lect. 2, n. 1292.

77 Ibid., lect. 2, n. 1293.

78 Ibid., lect. 2, n. 1292.

79 This remark of mine should not be misunderstood. In the case of substances and accidents, “being separable” should be clearly interpreted as a two-place asymmetrical relation (x is separable from y): substances are separable from accidents, whilst accidents are not separable from substances. I do not want to imply, however, that when applied to sensible objects and their ontological constituents, the notion of “being separable” should be taken as a two-place relation. In other words, I do not want to say that what Aquinas means is that matter and form are not separable from the composite, whilst the composite is separable from them. On the contrary, in this case “being separable” is a one-place predicate (x is separable) meaning something like “enjoying an independent existence”: the composite is separable tout court, whilst matter and form are not. What I wish to say is simply that this sense of “being separable” (the one-place sense) can help us to understand the relation between a sensible object and its ontological constituents. Of course, on the basis of the sense of separable which applies to the composite we can build up a two-place relation, which concerns, however, not the relation between the composite and its constituents, but rather that between two composite substances. Since each composite substance is separable in the one-place sense, it is also separable from any other composite substance (i.e. exists independently of any other composite substance). Note, however, that in this case the two-place relation is symmetrical and not asymmetrical as in the case of that between substance and accidents. I am separable from the dog in front of me just as she is separable from me. Probably, in this case “separate” would be a better rendering of the Greek χωριστóν.

80 Cf. Aquinas, Exp. Metaph., Lib. VII, lect. 2, n. 1292.

81 Ibid., lect. 2, n. 1293.

82 Cf. in particular Sancti Thomae de Aquino Quaestiones Disputatae De Anima, q. 1, Opera Omnia, t. XXIV, 1, ed. B.-C. Bazán (Roma / Paris, 1996), p. 7, ll. 192–205. But see also : Sancti Thomae De Aquino Sententia Libri De Anima, Lib. II, c. 1, Opera Omnia, t. XLV (Roma / Paris, 1984), p. 69, ll. 97–117; S. Thomae Aquinatis Summa Theologiae, Ia, q. 75, a. 2, ad 1 (Roma, 1962), p. 345; S. Thomae Aquinatis Scriptum Super Librum Sententiarum, Lib. II, d. 17, q. 1, a. 2, ed. R.P. Mandonnet, 2 vols. (Paris, 1929), vol. II, p. 418.

83 A partial exception to this general picture is the case of the human soul (cf. Aquinas, Q. De An., q. 1, pp. 7–10, ll. 192–341, where Aquinas raises the question of how the human soul can be at the same time a substance and the form of the body). Like all the other enmattered forms, the human soul does not satisfy the second of the two conditions for something to be a τóδε τι, i.e. it does not represent by itself a full-fledged member of a certain species. For a complete human being is not just a soul, but a soul in a body. Unlike the other forms, however, the human soul satisfies the first condition, in that it is capable of existing per se. The modal qualification “is capable” is important here, because Aquinas's claim is supposed to provide a philosophical explanation of the fact that the human soul outlives the body and so can exist – and will in fact exist – separately from it, even though it does not do so in this life. Thus, the human soul is not a complete τóδε τι, but is more of a τóδε τι than the other enmattered forms. For more on this doctrine see: G. Galluzzo, “Aquinas's Interpretation of Aristotle's Metaphysics, Book Zeta”, Recherches de théologie et philosophie médiévales, 74(2) (2007): 423–81.

84 Cf. Aquinas, Exp. Metaph., Lib. VII, lect. 2, n. 1293. See also: Sent. De An, Lib. II, c. 1, p. 69, ll. 100–101.

85 Ibid., lect. 9, nn. 1467–1469.

86 This is Aquinas's constant position since as early as the De ente et essentia and all through his career: cf. for instance S. Thomae De Aquino De ente et essentia, c. 2, Opera Omnia, t. XLIII (Opuscula IV), Editori di S. Tommaso (Roma, 1976), pp. 370–71, ll. 1–104; S. Thomae Aquinatis Liber De Veritate Catholicae Fidei seu Summa Contra Gentiles, II, c. 57, ed. C. Pera, 3 vols. (Taurini / Romae, 1961), vol. II, nn. 1329–1330. In his Commentary on the Metaphysics Aquinas attributes the view he defends to Aristotle and Avicenna and contrasts it with Averroes's. In the De ente et essentia, by contrast, Averroes is listed among the supporters of the view Aquinas himself advocates (De ent. et ess., c. 2, p. 373, ll. 274–291). In the light of my considerations in Section 2, it is clear that Aquinas's later account of Averroes's doctrine is more faithful to the Arabic Commentator's original thought. Di Giovanni (“La definizione delle sostanze sensibili”, pp. 56–63) maintains that, in the Expositio Metaphysicorum, Aquinas slightly misdescribes Averroes's position in order to attack some of his Latin followers. Aquinas's polemical intent is undisputable (Exp. Metaph., Lib. VII, lect. 9, n. 1467). However, if my reconstruction is correct, his characterisation of Averroes's general position is entirely correct. Of course, Aquinas translates the Arabic commentator's doctrine into his own philosophical jargon.

87 Cf. Aristotle, Cat., 1, 1a1–12.

88 Cf. Aquinas, Exp. Metaph., Lib. VII, lect. 9, nn. 1467–1469. For a detailed presentation of the distinction, see: De ent. et ess., c. 2, p. 373, ll. 274–291.

89 Aquinas is therefore right to say that according to Averroes forma partis and forma totius are not mind-independently, but only conceptually distinct (Exp. Metaph., Lib. VII, lect. 9, n. 1467). On this issue see: Di Giovanni, La definizione delle sostanze sensibili, pp. 45–56.