Plotinus’ Platonism shares sundry traits with that of the previous three centuries, but also introduces innovations in both method and content, which had lasting effects on later Platonism and the broader history of philosophy. Among them are an unprecedented critical engagement with Aristotle, a predominant focus on metaphysical questions and a multi-layered view of the structure of reality, based on a distinctive concept of causality.
This book addresses key issues at the intersection of these innovations, focusing on Plotinus and his two chief Platonist successors, Porphyry and Iamblichus, with additional substantive discussions of Peripatetics such as Alexander of Aphrodisias and Boethus of Sidon. It collects and revises eight papers published by C. in the last decade, adding two unpublished ones (‘Plotinus on Motion as Activity’ and ‘Universals and Secondary Substances’) and organising the total into three sections: (1) ‘Plotinus’ Ontology’; (2) ‘The Interpretation of the Categories’; (3) ‘Knowledge and Ethics’.
While the book announces no single overarching thesis, one can extrapolate from it the lineaments of a general picture of Early Neoplatonism. This emerges as a period of intense reflection, far less philosophically uniform than often thought, and in which confrontation with Aristotelianism sets considerable parts of the philosophical agenda. This picture is, I think, accurate, and the book does much to articulate it insightfully. Plotinus initiates a new phase, not an orthodoxy; and the history of Neoplatonism is not a succession of variations on a theme. That said, the greatest value of the book lies in the analysis of individual problems, arguments and texts, discussed with the philosophical depth, intimate knowledge of primary and secondary sources, and expository clarity to which C. has accustomed his readers, who will now be pleased to have these contributions conveniently collected in a single and nicely produced volume.
The opening paper, ‘Plotinus on Intelligible Qualities’, tackles the status of quality in Plotinus’ metaphysics, focusing on Ennead VI.2.14. Contrary to L. Lavaud's view that here and throughout VI.2 Plotinus distinguishes two levels of intelligible substance (primary, undifferentiated ousia, structured through the greatest kinds, and qualified ousia, articulated into particular ousiai thanks to intelligible qualities that act as differentiating factors), C. contends that qualities as such are absent from Plotinus’ intelligible world and have no role in either the structuring or the articulation thereof. Critical to this debate is the meaning in VI.2.14 of ‘particular substance’ (tis ousia), which Plotinus calls ‘composite’: for Lavaud it refers to each determinate intelligible species or Form (composed of genus and differentia), for C. to sensible substance (composed of sensible features). Strongly in the latter's favour militates the explicit mention at 14.6–8 of ‘numbers’, ‘quantities’ and ‘qualities’. But C. should have done more to show that in the chapter's closing lines ‘the human being itself’ is not an instance of ‘particular substance’.
The second and third papers, ‘Plotinus on Demiurgic Causation’ and ‘Plotinus’ Metaphorical Reading of the Timaeus’, deal with Plotinus’ interpretation of the Timaeus. C. convincingly illustrates it as a selective, non-literal and demathematised interpretation, counter to earlier post-Hellenistic Platonists. C. focuses on two guiding claims, suitably explained against the background of second-century ce debates between Platonists and Peripatetics. First, the demiurge is a metaphor for the Intellect; and its cognitive activity and causal efficacy are not expressions of practical rationality (since C. stresses a conflict with the littera of Plato's Timaeus, a comparison with modern non-literal readings of the dialogue would have been fruitful). Plotinus, like the Peripatetics, denies that cosmic order results from craftsman-like production, intelligent design and calculative deliberation, but also criticises their hylomorphic essentialism and natural teleology. Instead, he explains cosmic order through reference to metaphysical dependence upon extra-physical causes (here C.'s argument would have benefited from further clarification on how the Intellect causes order and what role the One-Good has in it). Second, Plotinus’ physics downplays the role (pivotal in the Timaeus) of geometric atomism and mathematics, favouring instead a ‘pseudo-hylomorphism’, which adapts Peripatetic ideas within a Platonist framework. One may wonder, especially in consideration of later Platonist joint developments of mathematics and metaphysics, what ultimately motivated this interpretative twist, in addition to Plotinus’ probable idiosyncrasy towards the mathematical aspects of Platonic thought.
The fourth, previously unpublished, paper, ‘Plotinus on Motion as Activity’, revisits Plotinus’ engagement with Aristotle's distinction between kinēsis and energeia. C. retracts his earlier interpretation of VI.1.16 according to which here Plotinus, criticising Aristotle's definition of kinēsis (motion as such is not incomplete, but an activity), distinguishes two types of motion and claims that only motion that is stricto sensu activity is produced by a supersensible cause. Re-discussing this text in relation to VI.3 (and criticising along the way M.F. Burnyeat's pronouncements on this issue), C. contends that it is in the latter that Plotinus addresses the proper causes of motion, by supplying the ‘kinematic’ perspective of VI.1 with a ‘dynamic’ one and drawing from Plato's Sophist (a point deserving further inspection).
Papers 5–7 deal with questions about the status of universals in both Peripatetic and Platonist interpretations of the Categories. The fifth, ‘Forms, Qualities, and Differentiae: Boethus of Sidon and Porphyry’, discusses Boethus of Sidon's view that only matter and compounds are substances, while form is a quality ‘in’ matter, and Porphyry's reaction to this Categories-centric ‘physics of inherence’, by drawing from Alexander, who hovers close at hand in Porphyry's ontology of the sensible. The sixth, previously unpublished, paper, ‘Universals and Secondary Substances’, perceptively outlines salient construals of secondary substance in Categories 5, contrasting Boethus’ particularism (no genera and species exist), with Alexander's essentialism (secondary substances are abstractable natures existing in particulars) and Plotinus’ rejection of the idea that primary and secondary substances fall under the same genus. The seventh paper, ‘Genera and Predication: Plotinus, Porphyry and Iamblichus’, reconstructs a momentous debate about genus, essential predication and metaphysical hierarchy. Its focus is Porphyry's original application of the genealogical conception of the genus in his account of the metaphysical hierarchy. This move, which breaks with Plotinus’ claim of the radical homonymy between intelligible and sensible substance, is attacked by Iamblichus in his lost commentary on the Categories and in his Reply to Porphyry (aka De Mysteriis).
The eighth paper, ‘Essence and Existence’, has a primarily negative intent: to argue, against various scholars (e.g. P. Hadot and L.P. Gerson), that Greek Neoplatonism did not formulate a distinction between essence and existence, nor did it claim their identity in the first principle. Providing a Stoic and Peripatetic context to pronouncements by Plotinus and especially Porphyry, C. argues that the distinction at issue is rather between a maximally indeterminate determinable of ‘what is real’ and determinate being or essence. Here I cannot discuss details, but it seems to me that both parties uncritically assume a rather narrow (scholastic) notion of existence and investigate whether it is found among Greek Neoplatonists. The latter could, however, still have a philosophical concept of existence (note that C. does not deny that they have an ordinary, pre-philosophical concept of existence) without thereby being ante litteram Thomases or Scotuses.
The last two papers explore the relationship between pre-philosophical and philosophical dimensions in epistemology and ethics. The ninth, ‘Common Conceptions and Philosophical Enquiry: Plotinus and Porphyry’, addresses the Plotinian view of the transition from common conceptions to philosophy (providing a persuasive context in Galen's De methodo medendi), then turns to Porphyry and situates the problem at hand within his discussion of philosophical disagreements. The final paper, ‘Ethics and the Hierarchy of Virtues from Plotinus to Iamblichus’, addresses the doctrine of degrees of virtue of Plotinus, Porphyry and Iamblichus, but with a distinctive emphasis on its connection to their metaphysical hierarchies.
One may raise doubts about this or that aspect or conclusion of these papers. But they invariably display conscientious, lucid, informed and philosophically stimulating scholarship, encouraging engagement by anyone concerned with Platonism, Aristotelianism and the history of ontology more generally.
