Alexander of Aphrodisias's Account of Universals and Its Problems

Alexander of Aphrodisias’s Account of Universals and Its Problems RIIN SIRKEL the philosophical problem of universals is traditionally framed as the problem about the ontological status of universals. It is often said that the ontological status of universals is a post-Aristotelian problem that was bequeathed to the Middle Ages by a famous sentence in Porphyry’s Isagoge.1 Porphyry raises but then refuses to answer three questions about the ontological status of genera and species, saying that they are too “deep” for the present investigation.2 Although Porphyry is the first to announce the problem, it was Boethius’s commentary on Porphyry, rather than the Isagoge itself, that made this sentence famous and that is therefore responsible for the problem of universals in the Middle Ages. However, when Boethius presents his solution to the problem of universals in his second commentary on Porphyry’s Isagoge, he claims to be following Alexander of Aphrodisias. Although Alexander’s contribution to the problem of universals is not yet generally recognized, his views on universals play an influential role in the development of the problem. Their influence can be found in Porphyry and Boethius, but also among the Arabic philosophers and the Scholastics.3 1 See, for instance, A. C. Lloyd, Form and Universal in Aristotle [Form and Universal] (Liverpool: Francis Cairns, 1981), 4. 2 Porphyry, Isagoge, 1, 10–14. The numerals refer to a page and lines of Greek text published in the series Commentaria in Aristotelem Graeca [CAG] vol. 4, part 1, ed. A. Busse (Berlin: G. Reimer, 1887). English translation of Porphyry’s Isagoge can be found in Texts on the Mediaeval Problem of Universals: Porphyry, Boethius, Abelard, Duns Scotus, Ockham [Five Texts], ed. and trans. P. V. Spade (Indianapolis: Hackett Publishing Company, 1994), 1–19. Porphyry’s three famous questions are “(a) whether genera and species are real or are situated in bare thoughts alone, (b) whether as real they are bodies or incorporeals, and (c) whether they are separated or in sensibles and have their reality in connection with them” (Spade’s translation, Five Texts, 1). 3 See Martin M. Tweedale, “Duns Scotus’s Doctrine on Universals and the Aphrodisian Tradition” [“Scotus’s Doctrine”], The American Catholic Philosophical Quarterly 67 (1993): 77–93; and “Alexander of Aphrodisias’ Views on Universals” [“Alexander’s Views”], Phronesis 29 (1984): 279–303. Tweedale argues that Avicenna, in particular, may have drawn on Alexander, as the common elements in their views are too numerous to be coincidental. * Riin Sirkel is a Doctoral Student of Philosophy at the University of Western Ontario. Journal of the History of Philosophy, vol. 49, no. 3 (2011) 297–314 [297] 298 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 Alexander of Aphrodisias’s views are important not only for understanding the medieval discussions of the problem of universals, but also for understanding Aristotle’s views on universals. Alexander, who was known to later generations as “the Commentator” (until Averroes took over that title), is usually taken to be a faithful follower of Aristotle, who rejected the Platonic account of universals in favor of Aristotle’s account. In light of this, it is noteworthy that Alexander’s views differ from the traditional understanding of Aristotelian universals. According to the traditional interpretation, an Aristotelian universal is a form: “Plato’s Idea put back into the individual.”4 This, in turn, implies that when Aristotle rejected Plato’s theory of forms, he did not reject the position that forms are universals but only the view that forms are separate universals. Consequently, the problem of universals is, in part, viewed as the opposition between two alternative positions: whether forms are or are not to be posited as existing on their own. On Alexander’s view, this problem is not primarily the problem of universals. For Alexander, the notions of form and universal do not necessarily coincide, since a form need not be universal (though it can be). Thus Alexander seems to be the first post-Aristotelian philosopher who explicitly defends a distinction between what it is to be a form, on the one hand, and what it is to be a universal, on the other. The aim of this paper is to explore Alexander’s account of universals, the difficulties it entails and the possible solutions to those difficulties. I focus on presenting a broad picture of Alexander without delving into particular and often controversial interpretive issues. I begin by analyzing the Aristotelian definition of a universal as that which is predicated of many things. In the second part of the paper, I will outline Alexander’s distinction between being a form and being a universal, as I understand it. In the third and fourth parts, I consider two problems this distinction introduces, viz. the problem about the ontological status of the form, and that of the universal. In the last part of the paper, I will briefly examine Boethius’s solution to the problem of universals, which he claims to take from Alexander, and which clarifies some of the problems raised by Alexander’s account. 1. The starting point for Alexander’s discussions of universals is the Aristotelian notion of a universal (katholou) as that which is predicated or said of many things. The locus classicus for Aristotle’s definition of a universal is De Interpretatione VII: Some things [pragmata] are universals, others are particulars. By universal [katholou] I mean that which is by nature predicated of many things; by particular [kath’ hekaston], that which is not; human being, for instance, is a universal, Callias a particular. (17a38–b2) This passage presents universals and particulars as two kinds of things, pragmata. This suggests, at the very least, that there are universals, i.e. universals exist. None- 4 George Brakas, Aristotle’s Concept of the Universal (Hildesheim: Georg Olms Verlag, 1988), 11. For a well-written overview of the traditional or “orthodox” interpretation, see Aristotle’s Concept of the Universal, 11–16; and Lloyd, Form and Universal, 1–2. Although the traditional picture has been challenged in recent decades, it is still the dominating interpretation of Aristotelian universals. alexander of aphrodisias on universals 299 theless, it is noteworthy that Aristotle’s definition of a universal, in and of itself, does not resolve the problem about the ontological status of universals. It does not tell us what precisely is predicated of many things, and can be interpreted as compatible with both realism and nominalism (or conceptualism).5 Accordingly, this definition leaves unclear the precise nature of the relationship between universals and particulars. In the Categories (2a34–b6), Aristotle famously argues that universals, i.e. things said of a subject, depend on particulars as basic subjects for their existence. When we understand his definition of a universal in light of the Categories, then it follows that universals cannot exist independently of particulars of which they are predicated. Stated otherwise, they cannot exist uninstantiated. However, Aristotle’s denial of the existence of uninstantiated universals does not follow from his definition of a universal alone. This definition may be interpreted as being compatible with universals that exist without being instantiated.6 I will not delve into the question about the ontological status of Aristotelian universals. Rather, I wish to draw attention to the question that concerns their instantiation. What does it mean to say that a universal is, by nature, predicated of many things? There are two possible interpretations. Aristotle’s assertion that universals are by nature predicated of many things might mean that for something to be a universal (i) it must be actually predicated of many things, or (ii) it must be such that it can be predicated of many things. What is at stake here? On interpretation (i), for a given universal to exist it must be multiply instantiated, i.e. its existence requires the existence of more than one particular. So if just one human being exists, the universal, human being, does not exist. The universal exists only when more than one human being exists. On this interpretation, the contrast between Callias and a human being can be expressed as a distinction between what is (non-homonymously) predicated of only one thing (Callias himself) and what is predicated of many things (say, Callias and Socrates) in common. This interpretation has one remarkable, though often overlooked, consequence. It seems that if we accept (i), then we cannot, at the same time, unambiguously assert that Aristotelian universals are forms. That is, if we accept that universals are actually predicated of many and we identify universals with forms, then it seems to follow that if there is only one particular in existence, this particular does not have its form. This result is clearly impossible, since for Aristotle form is the essence (ousia, to ti e-n einai) of a thing; it makes the thing be what it is.7 The implicit assumption here is that it is impossible for a thing to exist if its essence does not exist. So, if we accept (i), then we need to assume that the notions of form and universal do not necessarily coincide, or else we need to find some other way to deal with this bizarre consequence. On interpretation (ii), a given universal need not be multiply instantiated in order to exist. This interpretation allows us to assert that universals are forms, 5 As Lloyd says, this definition “allows at least three categories of things to be ‘said of’ or predicated of something: (a) linguistic entities, i.e. predicate expressions, (b) extra-linguistic entities, i.e. properties, (c) entities which are possibly intermediate, i.e. the ‘terms’ of his [Aristotle’s] logic” (Form and Universal, 3–4). 6 I am thankful to my anonymous referee for pointing this out. 7 See, for instance, Aristotle’s Metaphysics Z.1032b1–2, 1037a29, 1041b4–9; ∆.1017b15–16. 300 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 while avoiding the bizarre consequence mentioned above. For if there is only one particular, then it does not follow that its form does not exist, because the form can be shared by many things. However, this interpretation seems to entail another difficulty, for it does not make it necessary for universals to be instantiated in order to exist. If one holds that a universal is one which, by nature, is such that it can be predicated of many, then it is not clear why we should assume that it must be actually predicated of something at all. If a universal may hold of a plurality of things, even if there is, now, only one in existence, why should we not allow that some such universals hold of nothing at all? Thus, this interpretation seems to open a back door to Platonism, i.e. the view according to which universals exist regardless of whether or not they are instantiated. It is evident that Aristotle would not accept the position that a universal is something that can be predicated of many things even if none of them are in existence. Aristotle makes this very clear in the Categories, where he asserts that “if the primary substances did not exist it would be impossible for any of the other things to exist” (2b5–6). Aristotle is making a strong claim, viz. the existence of everything other than particular substances would be impossible were there no particular substances. From this it would follow that a universal conceived of as capable of existing on its own, independently of particulars, is an impossible entity—a fiction perhaps. Furthermore, in Metaphysics Z.13 he famously, and controversially, insists that universals are not substances. This suggests, minimally, that universals, unlike the Platonic forms or anything resembling them, cannot be said to exist as independent substances. So if one accepts (ii), then one needs to give an account of why universals are not, by nature, ontologically independent or separate from particulars. Interpretation (i) thus entails the troublesome possibility of a thing existing without its own form (assuming that forms are universals), and interpretation (ii) seems to lead to the Platonic position. What makes Alexander’s account of universals interesting is that he accepts, in a way, both of these interpretations yet applies them to different things. He accepts (i) and assumes that a universal is something that is actually predicated of many things.8 Consequently, he distinguishes between what it is to be a universal and what it is to be a form, and thus avoids the first difficulty mentioned above. However, Alexander seems to think that a form or nature is such that it can be shared by many particulars. Hence he also accepts (ii) and thus needs to deal with the difficulty concerning the ontological status of a form. I will begin my exposition of Alexander’s account with Quaestio 1.11 (and 1.3), where the distinction between the universal and the form is introduced and developed. 8 Thus Alexander’s position differs from what appears to be a majority view among modern scholars (if we can speak of the majority view at all in this case), who adopt interpretation (ii). See, e.g. R. W. Sharples, “Alexander of Aphrodisias on Universals: Two Problematic Texts” [“Alexander on Universals”], Phronesis 50 (2005): 43–55, at 44; Richard Sorabji, The Philosophy of the Commentators, 200–600 AD: A Sourcebook, vol. 3, Logic and Metaphysics [The Philosophy of the Commentators] (Ithaca, NY: Cornell University Press, 2005), 150. Sorabji writes, “This point, dependence on the existence of more than one particular, goes beyond Aristotle, for Aristotle’s definition of universals at Int. 17a39-40 requires only that a universal is shareable, whereas Alexander’s is actually shared” (150). alexander of aphrodisias on universals 301 2. Quaestio 1.11 is probably the most important and influential text on universals by Alexander. Its aim is to give an explanation of what is meant by the assertion in the first book of Aristotle’s De Anima that “animal, universal, either is nothing or is posterior.”9 Alexander’s explanation, however, goes far beyond Aristotle’s intention in the De Anima. He tries to understand what is meant by this claim in general, and takes up a definite position of his own on the question of universals. Alexander explains that in saying that “animal, universal, either is nothing or is posterior,” Aristotle added “universal” to “animal” to indicate “animal” as a genus. So, following Aristotle, he identifies the genus with a universal. Alexander begins by claiming that this universal is not merely nothing, but something (some being, ti on), for “it is not the case that, being nothing, it is universal and a genus and predicated synonymously” (Quaestio 1.11, 23, 22–23).10 So when Aristotle said “either nothing” he meant, Alexander explains, that the universal is not a thing in its own right (pragma ti kath’ hauto), being in the primary or proper sense, but something that is an accident of that thing. The origin of Alexander’s explanation can be found in Aristotle’s frequent criticism that Plato, in positing forms, made universals into particular substances, but that universals are not substances.11 If universals exist but not as particular substances, it is tempting to draw the conclusion that universals are some sort of accidents. It is controversial whether Aristotle would have accepted this conclusion.12 Alexander, however, is clearly committed to what Martin Tweedale calls the 9 This assertion occurs near the beginning of the first book of the De Anima, where Aristotle is setting the scene for his investigation of the soul: “[U]p to the present time those who have discussed and investigated soul seem to have confined themselves to the human soul. But we must be careful not to lose sight of whether there is one account of it, as of animal, or a different one for each—as of horse, dog, human being, god. The universal, animal, either is nothing or is posterior, and so too every other common predicate” (402b4–9; J. A. Smith’s translation modified). 10 References to Quaestiones give page and line numbers of Greek texts published in Supplementum Aristotelicum, vol. 2, part 2, ed. I. Bruns (Berlin: G. Reimer, 1892). References to Alexander’s commentaries on Aristotle give page and line numbers of Greek texts published in CAG. I will refer to his commentaries on the Metaphysics and on the Topics, which may be found, respectively, in CAG vol. 1, ed. M. Hayduck (Berlin: G. Reimer, 1891), and in CAG vol. 2, part 2, ed. M. Wallies (Berlin: G. Reimer, 1891). English translations of these texts are published in the Ancient Commentators on Aristotle series, ed. Richard Sorabji (Ithaca, NY: Cornell University Press, 1987–), and contain references to pages and lines of Greek texts in CAG (or Supplementum Aristotelicum). I rely on these translations, but I have revised them and retranslated words and entire sentences. 11 Aristotle argues against the Platonic approach in Metaphysics Z.13, 1038b35–1039a3; Z.16, 1040b26–30; M. 9, 1086a32–35. 12 There are few passages in Aristotle’s writings that suggest that he treats universals as some sort of qualities. In the Categories, for instance, he claims that genera and species signify a “quality of substance” (3b10–21). Although he insists that they do not signify simply a certain quality, as white does, one gets the impression that genera and species belong in the category of quality (see also Sophistici Elenchi, 178b38–179a10; Metaphysics, 1003a9, 1039a1). On the other hand, however, there are indications that genera and species represent for Aristotle a distinct sort of universal that cannot be reduced to or analyzed in terms of quantities, qualities, or other “accidents.” For instance, in the Categories he emphasizes more than once that genera and species are not “in a subject” (1a20–22, 8a7–15), which serves to distinguish them, or so it seems, from quantities, qualities and other categories. 302 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 “accidentality thesis,” viz. the idea that a universal is an accident of whatever it is that is universal.13 Alexander says the following: That of which the universal is an accident [symbebe-ken] is some thing [pragma ti], but the universal is not some thing in the proper sense [kyrio-s], but something that is an accident [symbebe-kos] of that thing. For example, animal is something and reveals [de-lo-tikon] some nature [physis], for it signifies [se-mainei] an animate being with sensation—and this in its own nature is not universal. (Quaestio 1.11, 23, 25–29) Alexander calls the thing in the proper sense (to which the universal belongs as an accident) a “nature” (physis). Elsewhere (e.g. Quaestio 2.18) he characterizes “nature” as the “source of change.” But here (as well as in Quaestio 1.3) “nature” is equivalent with “form” (eidos) and indicates a source or cause of being: something that makes the thing to be what it is.14 In Quaestio 1.3, Alexander says that “a human being is a human being in virtue of a nature of this sort, whether there are several sharing in this nature or not” (8, 15–16). Although a universal reveals or signifies a nature (e.g. “a human being” reveals “a mortal rational animal,” and “an animal” “an animate being with sensation”), Alexander insists that a nature in itself is not universal. This implies that the nature (i.e. form) is prior to the universal. Therefore, the universal either is nothing or is posterior because the universal is accidental to the nature of a given thing, and an accident is posterior to that of which it is an accident. Alexander offers the following argument to show that a nature is prior to the universal: That it is posterior to the thing is clear. For given the existence of an animal, it is not necessary for the animal as genus [genos zo-on] to exist (for it is hypothetically possible that there is just one animal . . . ). But if the animal as genus should exist, it is necessary also for an animal to exist. If an animate being with sensation were done away with, animal as genus would not exist (for it is not possible for what is not to exist in many), but if animal as genus were done away with, it is not necessary for animate being with sensation to be done away with, for it could exist, as I said, even in one thing. And it is for these reasons that he said: “either is nothing or is posterior.” (Quaestio 1.11, 24, 9–16) According to this line of argument, a nature is prior to the universal because a nature can exist without the universal, but not vice versa. Thus the sort of priority Alexander attributes to natures is the so-called ontological priority according to which one thing is prior to another, when the former can exist without the other, but not vice versa.15 Alexander argues if there were only one animal in existence, 13 See Tweedale, “Scotus’s Doctrine,” 79. In his commentary on Book III of Metaphysics, Alexander attributes this “thesis” to Aristotle himself: “For things which are universal have their being in the manner of accidents [tois gar katholou kata symbebe-kos to einai], as Aristotle will say further on” (233, 20–21). Although Aristotle does not say in Book III that universals are accidents, he does say that they are not substances. 14 In his commentary on Book V of Metaphysics (357, 5–360, 16), Alexander states that form is the fundamental sense of nature, and argues that the form is the intrinsic source of both change and being of natural things. Since Alexander does not distinguish between “form” and “nature” in Quaestiones 1.11 and 1.3, I will use them interchangeably. 15 Aristotle speaks about this priority “in nature and substance” in Metaphysics ∆.1019a2–4; see also Categories 14a30. Alexander explains in his commentary on Book V of Metaphysics that things prior in this sense are “those whose removal involves the removal of other things but that are not themselves removed when the other are” (387, 5–6). alexander of aphrodisias on universals 303 the animal nature (“animate being with sensation”) would exist, but the animal as genus would not. And since a nature can exist in only one particular, it is accidental to that nature whether it has more than one instance. Hence it follows that the universal is accidental to the nature. Alexander uses similar argument also in Quaestio 1.3 to show that the nature of human being need not be common to many particulars. If there were only one human being in existence, the nature of human being (“mortal rational animal”) would exist, even though the universal (human being as species) would not. Thus Alexander clearly assumes that a universal is something that is actually predicated of many things, i.e. the existence of a universal (e.g. human being as species) requires the existece of more than one particular. Simplicius, for example, attributes to Alexander the view that “it is impossible for there to be anything common (koinon) without the particular, but there are particulars without the common, e.g. the sun, the moon, and the universe.”16 So according to Simplicius, Alexander seems to think that although there is a sun, there is not a corresponding universal, since (according to the astronomy Alexander accepts) there are not many suns for it to be predicated of. A nature, on the other hand, is such that it can be common to many particulars, although in virtue of its own nature it need not belong to more than one. Thus Alexander avoids the above-mentioned difficulty that results from not keeping a form (i.e. nature) distinct from a universal by claiming that if there is only one particular in existence, then, although there is no basis for (actual) universal predication, the particular still has its nature. Alexander’s position that the universal is posterior to the nature of particulars implies that the universal is also posterior to the particulars that fall under it. Universals cannot exist without the particulars but not vice versa, since it is “hypothetically possible” that there exists just one particular. However, at the very end of Quaestio 1.11, Alexander suddenly and surprisingly makes the following claim: If one of the things that fall under what is common [to koinon] were done away with, what is common is not done away with along with it, since it exists in many. But if what is common were done away with, none of the things that fall under what is common would exist, since their being lies in having that [what is common] in them. (24, 19–22) The most evident problem is posed by the last sentence, which asserts that the common thing is prior to particulars on the grounds that their being consists in possessing (or instantiating) the common things. This problematic sentence can be interpreted in different ways. If we assume that ‘what is common’ (to koinon) is equivalent to ‘the universal’ (to katholou), then the last sentence of 1.11 conflicts blatantly with the account Alexander has just given of universals, according to which universals are posterior to particulars. Because of this conflict, Lloyd regarded the last paragraph as inauthentic.17 On the other hand, if we take this sentence as expressing Alexander’s own view, then he apparently gives more reality to universals than is usually thought.18 Porphyry, for example, makes particulars depend 16 Simplicius, Commentary on Aristotle’s Categories (CAG vol. 8), ed. C. Kalbfleisch (Berlin: G. Reimer, 1907), 85, 13–14. 17 Lloyd, Form and Universal, 51. 18 It is noteworthy that the last sentence of Quaestio 1.11 is not the only place where Alexander expresses such a view. In his commentary on Book V of Metaphysics he says, “For universals are prior in 304 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 for their existence on genera and species (see Isagoge 15, 12–13; 17, 9–10), and it has been suggested that he is following Alexander’s treatment of universals.19 However, this problematic sentence can be interpreted in a way that does not conflict with Alexander’s earlier account of universals. One way to avoid the conflict is to distinguish between the meanings of ‘what is common’ (to koinon) and ‘the universal’ (to katholou). For example, Pines has argued that while ‘to koinon’ refers to something that can exist in only one thing, ‘to katholou’ refers to something that must be predicated of more than one thing.20 Nonetheless, the problem with this interpretation is that Alexander seems to treat ‘to koinon’ as equivalent to ‘to katholou.’ A closer look at Quaestio 1.11 does not reveal any differentiation between the meanings of these notions, but rather an ambiguity with regards to ‘to katholou’ itself. That is, ‘to katholou’ can refer to what is actually predicated of many things (universal as universal, e.g. animal as genus), or to that which can be so predicated (to which being a universal attaches as an accident, e.g. animal as nature). Assuming that Alexander uses ‘to koinon’ and ‘to katholou’ interchangeably, it is reasonable to suggest that when he attributes to the common thing priority over particulars, he is not referring to the universal (as universal) but to a nature that can be universal or common.21 Now, the above interpretation is compatible with the account of universals according to which universals are posterior both to particulars and their natures. However, in suggesting that natures are prior to particulars, it invokes the problem concerning the ontological status of natures. This problem cannot be avoided regardless of how one interprets the last sentences of Quaestio 1.11, but it is especially obvious and pressing in light of the above interpretation. Does Alexander commit himself to the view according to which natures (i.e. forms) enjoy ontological priority over particulars in the sense that natures can exist without their particular instances, whereas particulars cannot exist without their natures? The ontological problem of natures will be the focus of the next part of the paper. their formula [logos], and they are also prior without qualification by nature . . . ; but in sense perception particulars are prior, and they seem to possess priority so far as we are concerned, but they are not prior without qualification” (386, 27–30). 19 See Sorabji, The Philosophy of the Commentators, 156–57. 20 Shlomo Pines, “A New Fragment of Xenocrates and Its Implications,” Transactions of the American Philosophical Society 51 (1961): 3–34, at 29. Pines continues, “The differentiation made by Alexander in this context between to katholou and to koinon appears to be an early formulation of the distinction between essences and universals which was to give rise to many mediaeval discussions” (30). 21 A similar interpretation is developed by Tweedale, who argues that although Pines is, in a way, right to suggest that Alexander’s view implies the above-mentioned distinction, “it is not a distinction which requires distinguishing the meaning of ‘common item’ and ‘universal’” (“Alexander’s Views,” 296). Sharples also seems to agree that when Alexander speaks of the common thing, he should be understood as speaking about a thing that can be universal. However, he modifies Tweedale’s interpretation on the grounds that the sentences just before the very last sentence of 1.11. make it clear that Alexander is speaking about the genus (and not the nature). He argues that Alexander may have applied to genus what actually applies only to nature and this “seems to be a slip resulting from the fact that species with only one member are the exception rather than the rule” (“Alexander on Universals,” 43). alexander of aphrodisias on universals 305 3. Although Alexander puts a lot of effort into showing that a nature is prior to the universal, he does not explain what precisely the relation is between natures and particulars. Alexander is usually considered to be a faithful follower of Aristotle, rejecting the Platonic account of universals in favor of Aristotle’s. However, there is some indication that his position is closer to the Platonic position than is usually thought. First of all, Alexander goes beyond Aristotle in his account of the Platonic position. Aristotle seems to take it for granted that Plato’s theory of forms is a theory of universals. If forms are not universals, then they are merely useless duplications of particular substances. Alexander, however, finds the distinction between forms and universals already in Plato’s philosophy. In his commentary on Book I of Metaphysics, where Alexander describes the Platonic position, he says the following: Having taken over from Socrates, then, the inquiry concerning definitions and the universal, Plato supposed that definitions are of natures of another sort and not of any particular sensible thing or of the universal over those sensibles [epi toutois katholou], because sensibles and all the things in them, and among these latter even the universal, are always in flux and changing and never remain [attached to] the same nature [epi te-s aute-s physeo-s menein]. . . . And these natures that are apart [para] from sensible things, and to which definitions belong, he called “forms” . . . (50, 7–15) Alexander suggests that the main difference between Plato’s and Socrates’ positions is that while Socrates sought definitions of universals and did not separate universals from sensibles, Plato supposed that definitions are of natures (i.e. forms) that are separate from sensible particulars, and not of universals present in sensibles. Alexander also emphasizes in his commentary on Book III of Metaphysics that the Platonists are committed to a position according to which forms are natures (or substances) in their own right, and exist “not in the manner of accidents [ou kata symbebe-kos], as the things that are common seem to do; for the existence of things that are common is not in their own right, but rather in the manner of an accident” (234, 32–34). The view Alexander attributes to the Platonists does not seem to be that different from his own position as it is expressed in Quaestio 1.3: “ . . . definitions are not of things that are common as common, but of those things to which it attaches as an accident [symbebe-ken] that they are common” (8, 12–13). In other words, the objects of definitions are not strictly universals but natures (i.e. forms) which need not be universal though they can be. Does Alexander, then, endorse some version of a Platonic theory of forms, freed from the burden of being a theory of universals? Secondly, Alexander seems to think that a particular is just the combination of a nature with material circumstances and individuating differences. So he says in Quaestio 1.3, “For mortal rational animal, if it is taken along with the material circumstances and differences that accompany their existence and that are different in different cases, produces [poiei] Socrates and Callias and particular human beings” (8, 1–3). It is difficult to see how a nature would be able “to produce” a particular, if not by having ontological priority over it. Does this imply that a nature can exist even if there are no particulars possessing it? 306 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 Alexander does not give explicit answers to the above-mentioned questions, but there is every indication that he would not admit that natures could exist without any particular instance. He takes pains to distinguish the view he is developing (and which he assumes to correspond to Aristotle’s view) from the Platonic view that posits separate forms. In Quaestio 1.3, Alexander emphasizes more than once that definitions are not “of some incorporeal nature that is separate from the particulars” (8, 7). Furthermore, near the end of Quaestio 1.3, he claims that the common things are “imperishable through the eternity of succession of the particulars in which they are” (8, 22–23). His claim that the common things are imperishable in so far as they are in particulars that eternally succeed one another also confirms that the existence of natures depends on the existence of particulars. So it seems that Alexander wants to endorse both the Platonic position that draws a distinction between being a form and being a universal, and the Aristotelian position that denies the separate existence of forms. One way to accommodate Alexander’s different claims is to rely on the solution proposed by Porphyry. In his commentary on Aristotle’s Categories, Porphyry struggles with the question of how to reconcile the Aristotelian claim that particular substances are primary with his own position that universals are ontologically prior to particulars.22 Porphyry suggests that although a universal is prior to each single particular that falls under it, it is certainly not prior to all particulars, for “you must not base the argument on a single human being but recognize that it is not one of the particulars which is a particular substance but rather all the particular human beings [in common] . . . ” (90, 30–32). Porphyry’s suggestion implies that a universal can exist without any given particular, although it cannot survive the removal of all particulars. Likewise, Alexander might have thought that the answer to the question of whether natures are ontologically prior to particulars is “yes” and “no,” depending on how the question is understood. The answer is “yes” if the particular is taken to mean any given particular. The nature has priority over particulars in a sense that its existence does not depend upon the existence of any given particular instance. But the answer is “no” if ‘prior to particulars’ is understood to mean prior to all particulars, for the existence of a nature requires that there is some instance of it. Indeed, near the end of Quaestio 1.11, Alexander says that “if one of the things that fall under what is common were done away with, what is common is not done away with along with it” (24, 19, my emphasis). If there were no horses, then there would not be a nature of a horse (“horseness,” as Avicenna would say). However, it is conceivable that this or that horse does not exist and yet there are horses, i.e. the horseness is present in some instances.23 Having said all this, it is still unclear what precisely is the status of a nature. Alexander only emphasizes in Quaestio 1.11 that the nature “in virtue of its own nature is not universal.” But does this mean that the nature is particular, or that 22 See Porphyry, Commentary on the Categories (CAG vol. 4, part 1), ed. A. Busse (Berlin: G. Reimer, 1887), 90, 12–26. In his commentary on the Categories, Porphyry does not attribute this position to himself, but he appears to be committed to it in his Isagoge (15, 12–13; 17, 9–10). 23 See also Sharples, “Alexander on Universals,” 52, who develops similar interpretation of the priority of a nature. alexander of aphrodisias on universals 307 the nature in itself is neither universal nor particular? There is some evidence supporting the latter alternative. The strongest evidence comes from Quaestio 1.3, where Alexander speaks of the nature as producing sensible particulars, when taken along with the material circumstances and individuating differences. This suggests that there is something which is prior to sensible particulars but which is somehow not (or not “yet”) a particular. But this is hardly satisfactory without further explanation, for it might suggest that a nature could exist without existing in particulars. This would be a Platonism that Alexander evidently wants to reject. Moreover, Alexander’s argument for the distinction between being a nature and being a universal relies on the hypothetical cases involving the existence of only one particular. But how could a nature existing in only one particular be something that is not itself particular? On the other hand, if we assume, as Lloyd24 does, that Alexander is committed to the position that forms are particular, then we seem to face another difficulty. Quaestio 1.11, in particular, suggests that a nature is something that can exist in many things, even though existing in many is accidental to the nature. How could a particular form or nature be the sort of thing that could exist in many things? I will return to these questions in the last part of the paper. In the next section, I will turn to the question concerning the ontological status of universals. 4. In Quaestio 1.11, Alexander treats universals as depending for their existence on the existence of particulars. More precisely, a universal exists only if a nature or form has at least two instances. It seems that the requirement of more than one instance does not make universals thought-dependent, since the existence of more than one particular does not depend on our thinking. Tweedale has suggested that Alexander’s universal is some sort of “accidental entity,” a Matthews-style “kooky object” that comes into being when a nature happens to have more than one instance and stops existing as soon as there is no longer more than one thing.25 It is unclear whether Alexander thinks of a universal as a real entity (“real accident”) that somehow pops into existence as multiple particulars come and go. But it is at least clear that Alexander’s account of universals has a realist side. Nonetheless, Alexander occasionally makes claims that appear to turn universals into something thought-dependent. In his commentary on Aristotle’s Topics, he clearly rejects the idea that genera are “mere thoughts without existence,” like the centaur (355, 12–14). But although universals are not mere fabrications of human imagination, they seem to somehow depend on the thought. In Quaestio 1.3, Alexander says that “the mortal rational animal, if it is taken along with the material circumstances and differences that accompany their existence and that are different in different cases, produces [poiei] Socrates and Callias and particular human beings, but if it is taken apart from these it becomes [ginestai] common” (8, 1–4). This suggests that while the nature “produces” the particular by being combined with material circumstances, it “becomes” common by being thought 24 Lloyd, Form and Universal, esp. chapter 4. Tweedale, “Alexander’s Views,” 295–96. 25 308 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 apart from matter. Likewise, in a passage from the De Anima26, Alexander speaks of things that are common or universal as “becoming common or universal,” and adds that “if they are not thought, they no longer are, so when they are separated from the intellect that thinks them they perish, if their being [einai] is in being thought” (90, 5–9). This suggests that universals cannot exist without being thought, i.e. apprehended by the intellect. Thus it seems that a universal ceases to exist when the apprehension of it ceases.27 These statements raise difficult questions. First of all, what is it that depends on the intellect for its existence? The suggestion that it is a form or nature is clearly problematic, for it implies that when no thinking of universals is occurring, then things do not have any natures. This implication can be avoided by suggesting that natures depend on thought not for their existence, but for their universality.28 So the form of human being, for instance, would not be universal or common to many, if there were no minds to think about it. On this suggestion, then, universals are mental constructions (as might be suggested by Alexander’s talk of form’s “becoming” common); there is no universality or commonness until thought gets to work. However, one might say that this suggestion is not wholly satisfactory either. For example, R.W. Sharples argues that it would not be odd to say that forms are only universal because they are being thought of, if Alexander would treat universals as mental constructions, but “Alexander seems rather to regard our awareness of what things have in common as a recognition of a nature that is already present in each of the individuals.”29 Indeed, Alexander treats the form as something that can be universal or common to many things, even if there is only one particular thing in existence. But if the form is a sort of thing that can be common to many, it is hard to see what stops it from being universal. Why should it also need to be thought? Sharples develops an interpretation according to which the thought is required for the form to be recognized as common or universal. This implies that there must already be some commonness for the thought to recognize. On this interpretation, what depends on thinking is not strictly a form’s commonness but the recognition of its commonness. Thus, it is not clear what precisely thought brings about in Alexander’s account of universals. Furthermore, it is not clear why universality should depend on thinking rather than on the existence of at least two particular instances. Are thoughtdependence and existence in more than one particular two different (or perhaps alternative) ways of being a universal? It seems that Tweedale would answer this question affirmatively. He claims that Alexander’s theory “borders on incoherence,” 26 Alexander’s De Anima (which is not yet published in English) may be found in Supplementum Aristotelicum, vol. 2, part 1, ed. I. Bruns (Berlin: G. Reimer, 1887). 27 Furthermore, in Quaestio 2.28 (78, 18–20) Alexander goes as far as to say that a genus taken as a genus is a “mere name,” not a thing that underlies, and it is common only in thought (noeisthai), not in reality (hypostasis). 28 A similar suggestion is made by Tweedale, who argues that “what ceases to exist when the form is not thought is an accidental entity called the universal man or the universal animal” (“Alexander’s Views,” 299). However, Tweedale emphasizes that the philosophical question Alexander leaves unresolved is the question of why the form’s commonness (and therefore the accidental entity which is the universal) should depend on the form’s being thought. 29 Sharples, “Alexander on Universals,” 47–48. alexander of aphrodisias on universals 309 for his “conceptualist tack seems at cross purposes with his often expressed view that universality or commonness lies simply in belonging to many.”30 Nevertheless, if we assume (in contrast to Tweedale) that thought-dependence and existence in at least two instances are not two different requirements for something being common or universal, then how can they be combined into a unified account? There are some indications that Alexander insists on both of these requirements.31 First of all, he gives a unified account of mathematical objects, but mathematical objects do not seem to differ from universals. In fact, Ian Mueller has argued that Alexander may have been a major contributor to the tendency to run together mathematical objects and universals.32 Alexander gives his account of mathematical objects in his commentary on Book I of Metaphysics, where he says, But mathematical objects reveal their likeness [to one another] in the many things, i.e. in sensible particulars, existing as they do in these; for these mathematical objects do not subsist [hyphestanai] independently, but by thought [epinoiai]; for after the matter and the motion have been separated [cho-rizesthai] from enmattered things, the things according to which and with which mathematical objects have their subsistence, these objects are left, revealing that likeness in enmattered things that are both many and different according to their accidental material circumstances. (52, 14–19) So mathematical objects do not exist in their own right, apart from material particulars. Alexander says that they are dependent on particulars and subsist in them. However, it is only when our thinking has separated the matter with which they subsist in particular things that these objects are left behind. This suggests that mathematical objects are some kind of abstractions.33 Thus, Alexander seems to hold that mathemathical objects exist in particular things and by thought (epionoiai) in the sense of being abstracted from material particulars. This might similarly apply to universals, since Alexander claims in his De Anima that “the products of abstraction [ta ex aphaireseo-s], such as the objects of mathematics, are similar to common things” (90, 9–10). However, Alexander does not expand on this analogy between mathematical objects and universals, and his account of mathematical objects is brief and at the most important point obscure. He does not explain what kind of abstractions the universals (and mathematical objects) are. Are they simply mental constructions, or is abstraction more like a discovery of something that is already present in enmattered things? In the above passage, the mathematical object is presented as a leftover of the mind’s separation of material circumstances. This might support the view that what is left behind must have been there before abstracting, though perhaps in a concealed form. In Quaestio 2.28, however, Alexander says that universals (genera) are “constructed [syntithenai] by a separation in thought [te-i 30 Tweedale, “Scotus’s Doctrine,” 81. See Sorabji, The Philosophy of the Commentators, 150–51. Sorabji thinks that Alexander has a unified account of universals. 32 Ian Mueller, “Aristotle’s Doctrine of Abstraction in the Commentators,” in Aristotle Transformed: The Ancient Commentators and Their Influence, ed. R. Sorabji (London: Duckworth, 1990), 463–80, at 469. 33 Mueller, (“Aristotle’s Doctrine of Abstraction in the Commentators,” 467) considers this passage as the most explicit statement of Alexander’s abstractionism. For a discussion of abstraction in Alexander, see Lloyd, Form and Universal, 55–56; and Sorabji, The Philosophy of the Commentators, 293. 31 310 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 epinoiai cho-rismos] of the other things which exist along with them” (79, 17–18). This seems to offer support for the view that universals are simply mental constructions. So although the above passage suggests that Alexander does not regard thought-dependence and existence in particulars as different requirements, it is not very clear how he intends them to be combined into one. A further piece of evidence in support of the view that Alexander combines thought-dependence and existence in many particulars into a unified account of universals comes from Boethius. In his second commentary on Porphyry’s Isagoge, Boethius claims to be adopting Alexander’s view, and the view he attributes to Alexander seems to be a unified view on universals. Boethius’s solution to the problem of universals will be the focus of the last part of the paper. 5. In his second commentary on Porphyry’s Isagoge, Boethius repeats Porphyry’s problems about genera and species and goes on to appeal to Alexander in presenting his solution. Just how Boethius’s solution is related to Alexander’s view is a controversial issue, not only because Alexander’s view is open to different and conflicting interpretations, but also because Boethius’s solution is difficult to interpret. In what follows, I will develop an interpretation of what I take to be Boethius’s solution. At the same time I will treat it as a possible interpretation of Alexander’s view, which helps to clarify some controversial aspects of Alexander’s account. Boethius’s solution to the problem of universals is, foremost, an answer to the first question raised by Porphyry, viz. whether genera and species really exist (sunt et subsistunt) or are merely thought of (i.e. formed by the thought alone) without existing in reality (see 83A).34 In order to understand his solution, I will briefly summarize Boethius’s discussion of this question and his arguments for and against the existence of universals. Boethius begins by arguing that everything that exists exists because it is one, and “everything that is common to many things at the same time [omne quod commune est uno tempore pluribus] cannot be one” (83A–B). Since genera and species are common to many at the same time, it follows that they do not really exist. This argument seems to imply that universals cannot exist at all, i.e. they are not entities (not even Tweedale’s “accidental entities”).35 If genera and species do not really exist, then they must be formed by the intellect and by thought alone. Boethius argues that although all thoughts are of 34 References to Boethius’s commentary give a column number followed by a letter (indicating the part of the page the text appears) of the Latin text published in Patrologia Latina [PL] vol. 64, ed. J.–P. Migne (Paris: Près la Barriere d’Enfer, 1847). An electronic version of the complete Patrologia Latina is available at http://pld.chadwyck.co.uk/. I rely on a passage from Boethius’s commentary which occurs in PL vol. 64, 83A–86A. The same passage is translated by Paul Vincent Spade, Five Texts, 20–25; and by Martin M. Tweedale, Abailard on Universals [Abailard] (Amsterdam: North-Holland Publishing Company, 1976), 64–86. 35 This central argument is reinforced by the curious infinite regress argument (83B–C), the point of which is not altogether clear. For an insightful discussion of this argument, see Paul Vincent Spade, “Boethius against Universals: The Arguments in the Second Commentary on Porphyry,” http://pvspade. com/Logic/docs/boethius.pdf. alexander of aphrodisias on universals 311 something, some of them derive from a subject thing “as the thing itself is” (ut sese res habet) and some do not. If thoughts that are genera and species derive from a subject thing “as the thing itself is,” then they would not be mere thoughts—they would also exist in reality, which is already rejected. But if they derive from the thing “as the thing itself is not” (ut res sese non habet), then they must be empty and false, where ‘false’ means something that is “understood otherwise than the thing is” (84B). So it seems that all enquiry into genera and species should be abandoned. If genera and species really exist, then it is difficult to see how they can be common to many. But if they do not exist in reality but are formed by thought alone, then it seems to follow that in thinking them the mind thinks of nothing. Boethius’s solution, which he claims to take from Alexander, seems to proceed by adopting the position that genera and species are formed by thought alone. It consists in rejecting the position that thinking of something in a way “as the thing itself is not” is always false or empty. More precisely, Boethius makes a distinction between two ways of forming a thought. The thought might derive from composition, e.g. “if someone joins a horse and a human being in imagination, and portrays a centaur” (84C). Such a thought, being a product of imagination (putting together what are separate in reality), is false and empty. But thoughts can also be formed “as the thing itself is not” by what Boethius calls “division” (divisio) or “abstraction” (abstractio). Thoughts formed in this way are not, Boethius says, false and empty. Thus Boethius appeals to a distinction that is already implicit in Alexander’s texts, namely, denying that the universals are “mere thoughts without existence,” like a centaur. Boethius illustrates the idea of abstraction with the example of a line. A line cannot exist separately from a body, for it owes its existence to the body to which it belongs. Yet the intellect can abstract it from the body and consider it without any consideration of the body. Like lines, the species and genera of corporeal things are bound up with bodies. Boethius argues that in their case, too, the intellect “distinguishes what is delivered by the senses as confused and joined with bodies in such a way that it may gaze and see the incorporeal nature by itself without the bodies in which it concretely exists” (84D, see also 85A). Thus he appears to adopt Alexander’s account of the abstraction of mathematical objects, but applies it more explicitly to genera and species. So far Boethius has been developing the position that universals do not really exist, but are formed by the intellect. But now difficulties emerge, for he continues by saying that universals do exist and that they exist in individuals: Thus these [species and genera] certainly exist in particulars, and are thought of as universals. A species is considered to be nothing else than the thought [cogitatio] gathered from the substantial likeness of numerically dissimilar particulars. A genus, on the other hand, is the thought gathered from the likeness of species. This likeness becomes sensible when it exists in particulars, and becomes intelligible when it is in universals. And in the same way, when it is sensible it persists in particulars; when it is thought of it becomes universal. Therefore, they subsist in the realm of sensibles but are thought of as apart from bodies. For it is not precluded that two things in the same subject are diverse in definition. . . . For the same line is concave as is convex. So too, for genera and species—that is, for particularity and universality—there is one subject. But it is universal in one way, when it is thought, and particular in another, when it is sensed in the things in which it has its being. (85B–D) 312 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 In this difficult passage Boethius tells us that the species is a thought (cogitatio) gathered from the particulars and that the species is a likeness (similitudo) that exists in particulars. What he means by ‘likeness’ is not overly clear. Sometimes he seems to think that the likeness is between particulars or species, and that it assists the mind in abstracting universals.36 More often, however, “likeness” seems to be the same thing as what Alexander calls a “nature” or a “form.” In Boethius’s account, it is the likeness that exists in sensible particulars and as a thought: in particulars it is sensible and particular; in thought it is universal. Boethius’s talk of “becoming” universal or sensible suggests that likeness (i.e. nature) in itself is neither universal nor particular. It “becomes” (fit) universal when it is thought of, and it “becomes” sensible when it exists in particulars. Boethius illustrates this idea with the analogy of a line that can be viewed as concave and as convex, depending on the point of view. The suggestion that the nature in itself is neither particular nor universal does not imply that the nature could exist without being one or the other (or both). Boethius, who takes himself to be presenting Alexander’s solution, does not embrace here the Platonic view of independent natures.37 He makes it clear that insofar as its being in sensible particulars is concerned, the nature is particular. So, even though nature is not particular in itself, it could not exist without being particular. The question then is what does really exist, and what is thought-dependent? It seems that Boethius takes the arguments against the reality of universals seriously and denies that the universal as such (as common to many things) could have real existence. Nonetheless, Boethius obviously wants to claim that the natures of sensible particulars really exist. Hence there is a sense in which universals exist too, viz. they exist in so far as the natures that can “become” universal really exist. His position that a nature exists in particulars as a particular implies that Socrates and Callias each have their own humanity and their own animality. Yet, through the process of abstraction the intellect views these numerically distinct humanities as one nature. Thus Boethius says in his commentary on Aristotle’s De Interpretatione that “humanity, gathered together from the natures of particular human beings, is reduced in a certain way to one [act of] comprehension [intelligentia] and one nature.”38 It seems that Boethius wants to deny that the nature, as it exists in particulars, is some one thing, prior to its apprehension by abstraction. This appears to be the point of his claim that species is a thought “gathered from substantial likeness of numerically dissimilar individuals.” So the natures of particular human beings are similar, but there is something they have in common, something one and the same for all only after the intellectual apprehension. Furthermore, Boethius’s talk of “likeness” could imply that he agrees with Alexander that at least 36 Alexander, too, speaks about “likeness” in this sense, when he says in his De Anima that “any apprehension which is a grasping of the universal by means of the likeness [homoiot tos] of the particular sensibles is an intellective act” (83, 11–12). Alexander talks about “likeness” also in the passage regarding mathematical objects that I presented earlier. 37 It should be pointed out that Boethius, unlike Alexander, is a Platonist, and in other texts he expresses views that are more Platonic (and Augustinian) than the view under consideration here. 38 Boethius, Commentary on Aristotle’s De Interpretatione (PL vol. 64), 464A. alexander of aphrodisias on universals 313 two instances of a nature each like the other must be involved before we have any chance of getting a universal.39 Therefore, when Boethius says that species (and genera) exist in particulars, he can be understood as referring to the particular humanities of Socrates and Callias. But when he says that species is a kind of thought, he is referring to the universal humanity that depends for its existence on being abstracted from the matter. It is those particular natures, “natures of particular human beings,” that are independent of the thought. What is thought-dependent is the universal concept that the intellect forms on the basis of their similarities.40 How does Boethius’s solution help to clarify Alexander’s account? First of all, Boethius gives a clearer answer to the question about the status of natures. Alexander only emphasizes that a nature in itself is not universal, thus raising the question of whether a nature is particular, or in itself neither universal nor particular. Boethius attributes to Alexander the position according to which a nature is something which in itself is neither universal nor particular, but which becomes universal when it is thought of, and becomes sensible when it exists in sensible particulars. Boethius’s proposal that the nature is particular when it exists in sensible particulars is more explicit than Alexander’s claim that in the particular things the nature is combined with material circumstances and differences. Boethius insists that natures “subsist in the realm of sensibles,” and thus avoids the troublesome implication that the nature could exist without existing in particulars. Secondly, Boethius gives a clearer answer to the question of what precisely is thought-dependent. He clearly rejects the suggestion that a nature depends on thinking for its existence. This makes his account compatible with the possibility that the natures of sensible particulars exist even when they are not thought of. Boethius adopts the view that natures depend on thinking not for their existence, but for their being universal. On his account, a nature exists in many particulars as a multiple thing—only after it becomes an object of thought will there be one nature, something that can be called the universal. Thus his account has the advantage of showing why Alexander might have thought of universals as dependent on thinking. However, in so far as Boethius seems to reject the suggestion, inherent in Alexander’s writings, that thought only discovers form’s commonness (rather than creates its commonness), he faces the difficulty of explaining what guarantees that universals as mental constructions are not false or empty. Abstraction abstracts something, and if what it abstracts has no existence before being abstracted, then abstraction becomes more like a fictitious invention than a construction that is not false. Boethius thinks that the intellect forms the universal concept on the basis of similaritities between particular natures, but one might doubt whether the appeal to similarity is a satisfactory solution.41 39 This suggestion is made by Sorabji, The Philosophy of the Commentators, 151. For a more detailed and critical interpretation of Boethius’s solution, see Tweedale (Abailard, chapter 2), who holds that Boethius’s solution is incoherent, as he “wavers back and forth between some conception of the universal as a reality independent of thought and another view of it as a ‘likeness’ in the mind” (83). 41 Clearly, this problem is not peculiar to Boethius’s account, but can be raised with regard to any nominalist position that appeals to the similarity or resemblance. Since resemblance is resemblance of something in some respect, it is tempting to reduce resemblances to universals. 40 314 j o u r n a l o f t h e h i s t o r y o f p h i l o s o p h y 4 9 : 3 j u ly 2 0 1 1 Thirdly, Alexander’s account seems to have both a realist side (universality lies in belonging to many) and a conceptualist side (universality depends on thinking), and it is not clear how those two sides can be combined into a unified account. Hence Tweedale concludes that Alexander’s account “borders on incoherence.” Boethius, however, offers (and ascribes to Alexander) a unified account of universals, and insists on both requirements for something being common or universal: the nature must subsist in at least two particulars and the intellect must abstract the universal on the basis of their similarities. So he seems to take realism and conceptualism as compatible alternatives. Boethius’s solution to the problem of universals suggests that he is a realist in so far as he thinks that universals have a basis in reality (the “basis” being particular natures); but he is a conceptualist in so far as he thinks that those natures are made universal by being conceived in thought.42 The aim of this paper was to explore Alexander’s account of universals, which has played an influential role in the formulation of the problem of universals. The interpretation I have developed suggests that the cornerstone of Alexander’s account is the distinction between a form (nature), on the one hand, and a universal, on the other. Thus his account differs from the traditional interpretation of Aristotelian universals according to which universals are forms. Alexander thinks that this distinction is clear if we consider that when there is only one particular possessing the nature, then the universal does not exist, but the nature itself does. I proposed that this explanation relies on a certain understanding of an Aristotelian definition of a universal as what is predicated of many things. For Alexander, a universal is not something that can be predicated of many, even if there is now only one thing in existence, but something that is actually predicated of more than one thing. By distinguishing being a universal from being a form, Alexander avoids the troublesome implication of a thing existing without its form or nature—if there is only one thing in existence, then there is no basis for universal predication, but the thing still has its nature. Although Alexander’s account avoids some of the difficulties that result from not keeping the universal distinct from the nature, it raises further problems. I focused on the problem of the ontological status of a nature, suggesting that Alexander’s position is closer to Platonism than is usually thought, and on the problem of the ontological status of a universal, suggesting that Alexander might be committed to the unified view of universals. In the last part of the paper, I sketched out Boethius’s solution to the problem of universals and suggested that Boethius, in so far as he treats natures as existing in particulars, and universals as existing in the mind, clarifies some of the problems raised by Alexander’s account.43 42 Boethius’s position is usually characterized as a “moderate realism.” This characterization might be misleading, for Boethius denies the reality of universals. His position is better captured by the scholastic description as a post rem cum fundamento in re, i.e. a conceptualism with a “real foundation.” 43 I am grateful to Henrik Lagerlund, Devin Henry, Richard Sorabji, Martin M. Tweedale, and Eik Hermann for their helpful suggestions and encouragement. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.