BMCR 2005.11.17

Aristotle and Other Platonists

, Aristotle and other Platonists. Ancient commentators on Aristotle. Ithaca: Cornell University Press, 2005. 1 online resource (viii, 335 pages).. ISBN 9781501716966. $49.95.

This is one of the most important and challenging books on Aristotle in recent memory. I think Lloyd Gerson is unlikely to persuade everyone of the truth of what he says. Nor perhaps will he convince anyone of the truth of all the things that he says. But if this book does not succeed in disturbing some dogmatic slumbers, I will be very surprised and more than a little disappointed.

Over the past decade or so we have seen a marked increase in the research done on the philosophy of late antiquity among Anglo-American scholars. The Neoplatonic Aristotle commentaries are being translated by Sorabji’s Ancient Commentators on Aristotle Project.1 Various Plato commentaries have appeared or will soon appear from various publishers.2 Sorabji’s latest contribution — the three volume Philosophy of the Commentators sourcebooks — seeks to sum up what this research has told us about the philosophy of late antiquity.3 But what does this strange Neoplatonist stuff mean for the study of Plato and Aristotle? Gerson’s is the first monograph-length treatment of this question in English. The thesis of his book is bold and easily guessed from the title: Gerson explores the Neoplatonic harmonization of Aristotle and Plato, and argues that there is far more merit to this position than is widely appreciated. At points Gerson stops short of fully endorsing the thesis of harmony between Plato and Aristotle. At points he stops short of fully endorsing it. It will be enough, he says, to clarify what an advocate of the Neoplatonic harmonia thesis must say about particular passages so that we can have a real debate about it (p. 23). Though Gerson has a lot to say about the various Neoplatonists and their slightly different understandings of the harmonia thesis as he goes along, his real objective is the harmonia thesis itself (p. 16). It is a book from which one can learn a lot about Neoplatonism, but it is most fundamentally a book about how the Neoplatonists can show us the right way — or at least a rather plausible way — to read Aristotle.

In order to argue meaningfully about this, Gerson must say what is meant by the purported harmony of Aristotle with Platonism and, secondly, what is meant by ‘Platonism’. The question of harmony should not be thought of as a matter of whether Aristotle thought of himself as in agreement with Plato, for certainly he did not (p. 10). Rather, Gerson says, the Neoplatonists thought of the harmony in terms of, first, a set of shared principles and, second, a philosophical division of labour. Plato was authoritative about intelligible reality, while Aristotle was authoritative about the sensible world. Nonetheless, Aristotle’s thought was deficient in not recognising a principle higher than thought thinking itself. This defect, together with their shared principles, meant that ‘Aristotelian philosophical claims could be subsumed under the more capacious and ultimately true Platonic system’ in a way analogous to the way in which sentential logic can be subsumed under predicate calculus or Newtonian mechanics under General Relativity (p. 4).

What then is Platonism and what are these shared principles? Gerson is clear that we must speak of Platonism, not merely the contents of Plato’s dialogues, when it comes to the Neoplatonists. Their conception of Platonism is one that runs contrary to several presuppositions that are widely shared by modern writers on Plato. First, they eschewed any developmentalist approach to the dialogues (p. 29). Moreover, they also relied on Aristotle for evidence of Plato’s Unwritten Doctrines (p. 30). It is crucial to keep in mind that the harmony that Gerson is investigating is that between Aristotle and this notion of Platonism broadly interpreted.

Gerson does not turn the critical spotlight on the content of the Platonism constructed from these materials. His mission is rather to identify the key themes in it and evaluate Aristotle’s Platonic credentials in light of them. The first feature of Platonism is what Gerson calls a ‘top down’ approach to the resolution of philosophical problems. Rather than seeking to explain phenomena by identifying the basic constituents from which they are composed (bottom-up-ism, exemplified by the atomists), the top down approach posits ‘higher’ irreducible principles whose existence entails the phenomena in question. More specifically, Gerson sets out the following core claims for Platonism: (1) the universe forms a systematic unity; (2) this systematic unity forms an explanatory hierarchy within which the simple and the intelligible are both ontologically and conceptually prior to the complex and the sensible; (3) the divine constitutes an irreducible explanatory category and, (4) so does the psychological; (5) persons belong to this systematic hierarchy, and happiness for them consists in a return to a position that they have lost; (6) moral and aesthetic valuation follows the hierarchy in such a way that the higher a thing is in the hierarchy the better and more beautiful it is; and (7) the epistemological order is included in the metaphysical order (pp. 32-4).

One may object that this is a capacious Platonism indeed and it is hardly any wonder if it should encompass Aristotle within its limits. Why, one might ask, is there not explicit mention of the theory of Forms? Gerson’s reply is that this list of core claims is intended to encompass all forms of Platonism and so must be drawn broadly (p. 34). This, however, seems to beg the question at issue. More concretely, Gerson points out that the Neoplatonists disagreed among themselves about the Forms. What was not in doubt was that there were intelligibles that were incorporeal and ontologically prior to sensibles. The Neoplatonists disagreed among themselves about the status of these noêta. Moreover, whatever Plato may have thought, the Neoplatonists did not regard these noêta as ontologically ultimate: there was still the One beyond Being. I think Gerson’s argument here is that it therefore makes no sense to regard the separation of the Forms as the issue that divides Platonists from non-Platonists. For, once we have accepted the One or the Good, the Forms or noêta are not themselves ontologically basic. Thus, we’ve already said goodbye to the separation question as we moderns understand it.

It matters quite a lot to the argument of the book how Gerson characterises Platonism. Suspecting (rightly) that those not congenial to the Neoplatonic reading of Plato will find this characterization tendentious, Gerson tries another approach. Take the philosophical views that are rejected in Plato’s dialogues. Assume that, if Plato argues vigorously against P, then the rejection of P and the consequences of such a rejection should be a part of Platonism (pp. 37-42). The rejection of Eleatic monism, Gerson argues, is tantamount to a rejection of any form of nominalism.4 The treatment of the giants in the Sophist shows that any Platonism must include a denial of materialism. The treatment of the friends of the Forms in that dialogue indicates that Platonism must include the activity of intellection together with the objects of intellect — a step toward the Neoplatonic conception of the Forms as a unified community of self-cognising intellects. The core of Platonism seen in this negative way consists in the drawing out of the consequences of the rejection of nominalism and materialism. Gerson claims that someone who failed to draw all the consequences from this rejection that Plato did may still be reasonably thought to be in harmony with Plato (p. 42). More positively, the remainder of Gerson’s book seeks to show that Aristotle did join Plato in drawing many of the same consequences from the rejection of nominalism and materialism.

I have two comments on this method. First, the theses enumerated as 1-7 above are not all entailed by the rejection of nominalism or materialism. There is thus significant gap between Gerson’s positive characterisation of the core theses of Platonism and his via negativa. Second, the juxtaposition of these two paths raises a question in my mind about what Gerson’s agenda really is. I think theses 1-7 do capture key themes in the Neoplatonic reading of Plato. If this is what one means by Platonism, then Aristotle’s Platonic credentials look pretty good. I also think that Plato rejects nominalism and materialism. But to suggest that this rejection plausibly yields the Neoplatonic version of Platonism is to suppose, not only that Plato’s dialogues can be read as the Neoplatonists read them, but that they must be. I think I am probably willing to concede much more plausibility to the Neoplatonists’ reading of Plato than many people in the business. But I’d not like to argue that they are the inevitable working out of the pointers that Plato gives us. I sometimes wonder whether Gerson doesn’t really think so deep down. That’s not meant as a criticism. It is just that it is an additional premise — one clearly beyond the scope of the book — that it seems to me sometimes intrudes into the argument.

It is said that the proof of the pudding is in the eating. And so it is with this book. After these opening moves, Gerson gets down to the job of reading Aristotle through the lens of the Neoplatonic harmonia thesis. Even if the reader was not wholly satisfied with the case made from on high, the particular detailed cases are worthy of careful attention.

Chapter 2 considers Jaeger’s thesis that Aristotle’s exoteric works represent an early, Platonic phase of his career, while the esoteric works reveal his evolution beyond Platonism. Gerson notes the contortions that are required here: parts of On Philosophy that are critical of the theory of Forms seem hard to square with the Jaeger thesis. From the harmonist perspective, however, Aristotle’s criticisms of the theory of Forms is a disagreement within Platonism about the status of intelligibles. Since Aristotle accepts the existence of an immortal intellect (viz. the prime mover), he must equally accept the existence of eternal objects of intellection or noêta. The question at issue, then, between him and Plato is only one about the nature of the intelligibles, not their existence.

Criticism of Jaeger’s developmentalist approach to Aristotle’s works is a key theme throughout the book. Gerson is anxious to press the claim that, viewed in the context of the harmony hypothesis, Jaeger’s view looks question-begging. Certain works of Aristotle must be early because they are too much like Platonism. But Aristotle is not a Platonist since he criticised the Forms. But this line of argument assumes, without argument, that the mature Aristotle is anti-Platonist through and through. It does not leave room for the thought that Aristotle is better thought of as a ‘dissident Platonist’ — a characterisation more in keeping with Gerson’s view and that of the Neoplatonists.

Chapter 3 takes up the question of the extent to which one must see the author of the Categories as anti-Platonist. Gerson notes that a developmentalist assumption makes a lot of difference here. Since the Neoplatonists hold no such assumption, they take the skopos of the work to be ‘words in as much as they signify things’. It is not a work of ontology. If Aristotle says here that this particular man or that horse are primary substances while he implies otherwise in Metaphysics, that is because in Categories he is concerned with language. With respect to our linguistic expressions, sensibles are primary substance, while with respect to nature, intelligibles are primary (cf. Porphyry, in Cat. 91, 19-27). Nor does the distinction between ‘present in’ and ‘said of’ conflict with Platonism. Plotinus is happy to acknowledge that there is a sense in which ‘Socrates is pale’ says what Socrates is like, while ‘Socrates is man’ says what Socrates is. But he rejects the claim that one should answer the question, ‘Is this man?’ in the same way with respect to both Socrates and the Form. Essential predication should identify, but Socrates is much besides what the Form of Man is (p. 89). The Neoplatonic interpretation of the Categories has had extensive treatment in the literature. However, Gerson draws together the considerations about Alexander’s treatment of individuals, natures and universals with the Neoplatonist material. He also offers replies to those, like Daniel Graham, who suppose that Aristotle must have changed his mind between Categories and Metaphysics.

The next chapter is dedicated to an examination of Aristotle’s physical theory and his account of explanation. In the former case, Gerson argues that the Neoplatonists simply saw a division of labour, not conflict. In the latter case, the Neoplatonists added to Aristotle’s four causes ‘the paradigmatic cause’ (Simplic. in Phys. 3, 16-18). This is an illustration of the subsuming of Aristotle’s theory of nature under a more complete Platonism. Gerson suggests that the harmonist view helps shed light on the problem of matter and definitions (cp. Metaphys. 1045a34 with 1039b27), the relation of final to formal causality, and the influence of the prime mover. In a densely argued chapter, Gerson seeks to show that in each case, the best resolution of these puzzles is one that moves Aristotle closer to the concept of a paradigmatic cause and to a picture of god functioning like the Demiurge in the Timaeus.

Chapter 5 takes up the question of soul and intellect. Gerson argues against those who seek to downplay the importance of intellect in Aristotle or to discount the claim that it is separable. Moreover, it is intellect in the singular that is at issue: Gerson argues that De An. III.5 does not introduce a second, active intellect, nor is the subject of this chapter the divine intellect. He quotes the exegesis of this passage by Ps-Simplicius ( in DA 246,17-248,16) and builds a case that the author is not wrong to see basic agreement between Plato and Aristotle. Most Neoplatonists take Plato to be committed to the immortality of the rational part of the soul, i.e. the intellect. Since Aristotle is too, they are basically in agreement.

But what, you may say, about the Metaphysics ? Surely this is anti-Platonic in a variety of ways. First there is the question of what Aristotle takes first philosophy — the science of being — to be a science of. Is it the study of being qua being? Or is it theology? Neither of these seems to be the same as the study of Forms. There is, of course, a vexed history of trying to figure out the relation between Aristotle’s apparently competing answers. The Neoplatonists supposed that they were one and the same: the being of separate, non-sensible, intelligible objects (i.e. gods) is the focal meaning of ‘being’. Theology and the study of being qua being thus coincide. It is true that the Neoplatonists object to Aristotle’s Prime Mover as the first principle of all things. The Prime Mover’s activity of self-intellection has a complexity that they claim presupposes a further, more fundamental simplicity — the One (p. 189). Moreover, Gerson sides with the Neoplatonists who suppose that Aristotle’s God thinks all intelligible objects, not just himself. He notes the convergence between the Neoplatonist’s view and Kahn’s characterisation: ‘the Prime Mover is simply the formal-noetic structure of the cosmos as conscious of itself.5. Such an interpretation, Gerson suggests, makes better sense of divine causality in Aristotle (p. 204).

Then there are Aristotle’s criticisms of the theory of Forms. Here Gerson first gives the Neoplatonic view of the Forms. They do not accept an unlimited One over Many assumption when it comes to the range of Forms. Moreover, by their lights, there is more common ground between Aristotle and Plato on the relation of the Forms to the divine. While the Forms are not thoughts ( noêmata) in the mind of the Demiurge, these noêta are not separate from the divine nous either. Gerson says that the Forms and the activity of the divine intellect are ‘extensionally equivalent’ (p. 215) or ‘cognitively identical’ (p. 218). If I understand him correctly, the latter is the relation that results when essentially self-reflexive cognition of a cognizable object takes place. In such cognition, the object of cognition is present in the intellect and the intellect is aware of itself as that in which the object is present (p. 139). This seems to involve a duality that yet falls short of numerical distinctness. Finally, the Neoplatonist interpretation of Plato’s Forms makes them products of higher principles, such as the One and the Indefinite Dyad.

When Plato’s theory of Forms is read in this way, how will Aristotle’s criticisms of it appear? In the interest of space, I will concentrate on what Gerson himself regards as the objection that seems to set Aristotle most at odds with Plato. If Forms are universals and thus predicable of many, then they cannot be separate and substances, for all substance signifies ‘some this’ or tode ti ( Metaphys. 1003a7-13; 1038b35ff). By making Forms both separate and predicable of many, Plato makes them impossible objects — things that are both universals and particulars. For the Neoplatonist response to this line of argument, Gerson refers to Asclepius commentary on Metaphys. I.9. According to him, Aristotle here disagrees with those who posit the Ideas as existing apart from Intellect.

How does this insistence that the intelligible Forms are not outside the Intellect help with Aristotle’s problem? Gerson thinks that it does so by permitting a distinction between the Form and its nature (p. 222). The Form, while it is thought universally in the Demiurgic mind, does not function as a universal. It is the participated form — the Nature — that is predicated of the many. It seems to me that Gerson takes the Neoplatonic distinction between the unparticipated and participated Forms to involve a division of labour. The unparticipated Form is substance and cause. The participated form, or enmattered form, is the Nature common to all the things of which the predicate is true. But the unparticipated, transcendent Form is not explanatorily idle insists Gerson. While the enmattered form explains why this man and that man can both be called ‘men’, the unparticipated Form grounds the eternal possibility that anything could be a man (p. 226). This ‘paradigmatic cause’ is alien to Aristotle’s framework of the four causes. In his Metaphysics Commentary, Asclepius is happy to agree with Aristotle that ‘man begets man’, i.e. the transcendent Form does not enter into the explanatory framework of particular events or things. But the possibility that many things should be identical to one another in respect of being man is still presupposed. This is what the paradigmatic cause explains. Asclepius counts Aristotle on the side of Plato because Aristotle shares with Plato a commitment to the idea that the very possibility of a universal that is one and the same nature across the many instances is something that stands in need of an explanation (p. 226).

But is Asclepius right to do so? It seems to me that if anything secures the possibility that ‘man’ is predicated of many for Aristotle, it is the universal plus the eternity of the species. What else is there that needs to be explained? Since there always have been and always must be human beings, the possibility of more things of the same kind is secured without recourse to an unparticipated Form. I have toiled long enough in the engine room of Neoplatonic translation projects that I can see how the concepts of participated and unparticipated Forms are connected. (Gerson might have pointed to Simplicius in Cat. 83,10-14 for a differentiation of the transcendent common cause (i.e. unparticipated Form) from the enmattered common nature (i.e. participated form). However, I think more factors than Gerson has discussed here led the Neoplatonists to accept both a common nature and a transcendent cause. There is a mysterious connection between modes of being and causation. (Well, at least it is mysterious to me.) The Neoplatonists must have both the participated and unparticipated Form because a) they posit an ordered series of modes of being — these modes typically being distinguished by adverbial forms — and b) have a principle of explanation in which each property exhibited in a subordinate mode must be explained by appeal to that property exhibited in one of the superior modes. These are linked. What is F in the primary mode ( prôtôs) is F in a causal preparatory way ( kat’ aitian) and is regarded as unparticipated. What is F in a derived way ( deuterôs) is F in actuality ( kath hyparxin) and is regarded as participated. I think Proclus’ Elements of Theology prop. 18 and in Parm. 880,1 ff argue for both the participated and unparticipated Form on the basis of these principles. While I can rehearse these arguments, I cannot in the final analysis understand them, because I cannot really comprehend what it means for there to be ‘modes of being’, nor can I see any philosophical point in the Neoplatonists’ insistence on their explanatory principles. For this reason, I have trouble seeing the Neoplatonic version of either Plato or Aristotle as responsive to metaphysical worries that I can entirely recognise as my own.

Gerson’s chapter on Aristotle and the Forms is not his last word. Another lengthy chapter considers Aristotle’s ethics from the point of view of the Neoplatonic harmonia thesis. He first provides a summary of Neoplatonic moral philosophy, and in particular their conception of the gradations of virtue (Plot. Enn. I.2; Porphyry, Sent. 32). Turning then to Aristotle, it is unsurprising that the question of the inclusivist versus the dominent end reading of Nicomachean Ethics is the first topic. Gerson sees Aristotle writing an ethics for us in our dual identity. On the one hand, we are composites — embodied intellects. On the other, we are divine intellect and we should seek to identify with it as the true self. The current debate about Aristotle’s ethics misses the point about the personal transformation that results from identification with the intellect, a theme that is much discussed in the literature on Plotinus. Gerson concludes by arguing for the Platonic antecedents of the Aristotelian idea of virtue as a mean. Moreover, Gerson argues, such a conception of virtue presumes a Platonic conception of personhood as identification with the intellect and a corresponding subordination of ethical virtues to theoretical virtue.

A final chapter returns to the opening themes and asks whether any consistent Aristotelian must find himself in harmony with Platonism understood as broadly as Gerson understands it. The argument here is too complex to be treated in a review. Gerson argues, in effect, that no rejection of nominalism can stop short of Platonism. Central to this argument is a distinction between form and universal in Aristotle, and also the claim that the Prime Mover thinks all intelligibles, not merely himself. The second element of the chapter concerns the distinction between persons and human beings. According to Gerson, Aristotle’s epistemology places him much closer to a Platonic dualism than those who see him as a proto-functionalist would accept. We do not cognise representations of forms on Aristotle’s view. Rather, the soul really is ‘the place of forms’ ( De An. 429a27) and they are, in a sense, in it when we understand. Thus Cornford’s twin pillars of Platonism — the existence of the Forms and the immortality of the soul — also underpin Aristotle’s Platonism. He accepts the immortality of the cognising intellect and the ontological priority of the forms cognised by it. Aristotle’s philosophy is conditioned by the acceptance of premises that are ultimately Platonic and these Platonic assumptions cannot be successfully disentangled from it (p. 290).

This is a very challenging book. For those who are specialists in the area of the commentary tradition, it will focus your mind on the significance of Neoplatonism for our understanding of Plato and Aristotle. For those who are well versed in the philosophy of Plato and Aristotle, though not perhaps in the commentary tradition, it will be a steep learning curve. Nonetheless, there is an extensive bibliography, an index locorum and a ‘who’s who’ of all the players in the commentary tradition. I urge anyone who is feeling somewhat stifled by the status quo in Aristotle scholarship to take a good hard look at this book. Even if you disagree profoundly it will — and I think should — open your mind to some new possibilities.


1. Duckworth and Cornell University Press. The first in the series was Philoponus’ Against Aristotle on the Eternity of the World, trans. C Wildberg (1987). There are now 61 volumes, the most recent being Michael Share’s translation of Philoponus’ Contra Proclum (2005).

2. Australia is growing its export economy through Neoplatonic Plato commentaries. See Jackson, Tarrant and Lycos, Olympiodorus: Commentary on Plato’s Gorgias (Brill: 1998), and Baltzly, Runia, Share and Tarrant, Proclus: Commentary on Plato’s Timaeus, 5 vols (Cambridge, forthcoming).

3. Richard Sorabji, The Philosophy of the Commentators: A Sourcebook, 3 vols. (Cornell University Press and Duckworth Press, 2005).

4. The connection here is not immediately transparent. Gerson is borrowing a line of argument from R. E. Allen, Plato’s Parmenides (Univ. Minnesota Press, 1983), 80.

5. Charles Kahn, ‘On the intended interpretation of Aristotle’s Metaphysics’ in Aristoteles Werk und Wirkung: Aristoteles und seine Schule, J. Wiesner (ed), (Walter De Gruyter: Berlin, 1985), p. 327.