Plotinus Ennead II 5. On What is potentially and What Actually, Parmenides Publishing, Las Vegas/Zurich/Athens, 2015.
Ennead ii.5. On what is potentially and what actually, with an introduction, translation and commentary by Cinzia Arruzza, is the sixth volume out of the nine already published in the Plotinus Series (The Enneads of Plotinus with Philosophical Commentaries) of Parmenides Publishing. As in the previous volumes, the book opens with an Introduction to the Series (p. 1-10) by its editors, presenting the most important facts of the life of Plotinus, together with the fundamental themes and intuitions of his philosophy. It is followed by a list of Abbreviations (p. 11-2)—comprising the editions of the Enneads, the Addenda to the text and the instruments concerning the Greek language and the history of Ancient philosophy used in this volume—and the Acknowledgments (p. 13-14) of the author.
Ennead ii 5 is quite small, counting only five chapters, but it is a difficult and important treatise in that it discusses two technical notions with a long philosophical history. In her Introduction to the treatise (p. 15-43) Arruzza gives a useful overview of the basic moments of this history, namely the appearance of the notion of dunamis in Plato; the evolution of this notion, together with its counterpart energeia (or entelecheia), into an explanatory scheme of great philosophical importance in Aristotle; and the notion of dunamis and its correlate logos in the Stoics. Arruzza starts by examining the definition of dunamis in the Republic as the capacity to act or be acted upon, belonging to a specific class of beings; and the formulation in the Sophist of a new definition of the term: it is now the genus ‛being’, itself conceived of as dunamis koinonias, as a “power of communication”, which enables beings to relate with one another. She then turns to the pair dunamis-energeia, which constitute two central notions in Aristotle’s physics, metaphysics and biology. Arruzza gives an enlightening outline of the different meanings of dunamis in Book Δ, of the discussion of the difficulties associated with the use of the pair dunamis-energeia, in Book Θ of the Metaphysics,1 and of the use of dunamis to talk about the faculties of the soul in the De Anima. She shows that a number of points which emerge from this outline are important for Plotinus: the distinction between active and passive potentiality; that energeia, being ontologically prior to dunamis, refers to the form and substantial existence of a thing, whereas dunamis denotes its matter; that dunamis also denotes a capacity to act and in this sense it can be used to refer to the faculties of the soul; that energeia, as the actualization of a dunamis, refers either to an actual thing or to an activity. Finally, Arruzza rightly stresses that in Metaphysics Λ eternal substances are pure acts, containing no potentiality whatsoever. Lastly, she examines the Stoic conception of their active principle as a self-moving dunamis which shapes and informs the universe, noting that although Plotinus rejects the corporealism of the Stoics, his thought is heavily indebted to their conception of the seminal logoi as formative powers. The Introduction continues with an outline of the Plotinian conception of potentiality and actuality in the Enneads. Arruzza examines the notion of active power (dunamis) which Plotinus attributes to the intelligible realities in order to explain their efficient causality. The Introduction closes with a brief outline of Ennead ii 5.
The Introduction is followed by a Note on the Text (p. 45) stating that the Greek text adopted is that of the Oxford edition (i.e. HS2, taking into account the Addenda ad Textum in vol. 3, i.e. HS4); and the Chronological Order of the Enneads (p. 46), presenting the correspondence of the systematic order in Porphyry’s edition with the chronological order, according to his Vita Plotini. The Translation is preceded by a helpful Synopsis (p. 47-50) comprising the basic questions and theses of each of the chapters. The translation itself (p. 51-60) is careful, precise and fluid. There are no notes accompanying the translation, but in the Commentary Arruzza offers careful discussions of the alternative readings she adopts, and of emendations that have been proposed by other translators.2
The Commentary (p. 51-173) takes up the biggest part of the book. I found the discussion of Plotinus’ reading of Aristotle in the first chapter of the Commentary particularly interesting. In the first chapter of the treatise Plotinus interprets Aristotle with the view of establishing the identification of potential being (to dunamei) with passive potentiality only. In order to do that, Arruzza argues, Plotinus does not adopt the Aristotelian distinction between qualitative change (i.e. alteration) and substantial change (i.e. generation). The Aristotelian conception of alteration entails that the substrate remains a tode ti throughout the change. Plotinus, who in the second chapter will argue against any continuity in the process of change, opts instead for another Aristotelian distinction, one between two kinds of substantial change, the schēmatisis, i.e. the taking on of a new shape, and substantial change proper, i.e. generation, because both these kinds of change treat the substrate as matter and not as substance.
In the second chapter Arruzza discusses Plotinus’ position according to which, when a new thing is generated, there is no passage from potential being to actual being. On the contrary, the new form which appears on a substrate does not consist in the actualization of a potentiality already contained in the substrate, but comes from an altogether different instance, namely the adequate formative principle. The thing which comes to be is, thus, different from the potential thing. Arruzza argues that Plotinus holds this to be the case for substantial change only, not for alteration.
According to Arruzza, chapter 3, where Plotinus argues against there being any potentiality in the intelligible, is the “heart of the treatise”. Plotinus establishes that intelligible beings, including souls, are active powers, which are always in actuality, this being in fact identical with their self-referential and self-constituting activity.
Chapters 4 and 5 form a unity dealing with the impossibility for matter to change from a state of potentiality to a state of actuality. This impossibility, Arruzza rightly stresses, rests on Plotinus’ identification of matter with prime matter. Being entails being in actuality; matter is non-being, therefore it is not in actuality. Since matter is not one thing in potentiality, whilst being also something else in actuality, it can never be in actuality. If prime matter is all things in potentiality, then it can be no one thing in actuality. Whether Aristotle held there to be prime matter is a controversial question; Arruzza’s suggestion is that Plotinus may have found the notion of prime matter in Alexander of Aphrodisias. The conclusion of the treatise is to posit matter as utterly separate from anything that belongs to the realm of form.
The book closes with a Select Bibliography (p. 175-188) and two useful indices, an Index of Ancient Authors (p. 189-193), comprising the citations by Arruzza of Plotinus and other ancient authors in the Introduction and the Commentary, and an Index of Names and Subjects (p. 195-201).
The aim of the Plotinus Series is to provide well informed guidebooks for scholars interested in the thought of Plotinus, rather than complete philosophical commentaries. On this account, Arruzza’s book provides the reader with an excellent translation and a clear and informative discussion of Plotinus’ arguments. I can’t help but wish, though, that in her Commentary she had taken into consideration the subsequent development of the arguments of this treatise. As I already mentioned, Arruzza claims that chapter 3 is the core of the treatise since Plotinus’ aim is to establish the efficient causality of intelligible beings, and more precisely of souls with regard to sensible things. Although this is beyond doubt, Plotinus cannot establish this efficient causality fully and completely if he does not do away with any possibility for matter to contribute in any causal way to the constitution of sensible reality. This, in my opinion, explains why the largest part of the treatise deals not with actuality and intelligible beings, but with potentiality and matter. Arruzza rightly notes in her Introduction that the arguments of Ennead ii 5 are further developed in treatises iii 6, concerning the impassibility of matter, and iv 3 about the active power of the soul informing the sensible realm—these two treatises immediately following ii 5 in the chronological order. I believe that had she brought into the discussion the notion of the impassibility of matter, which rests on the break up of the continuity between potentiality and actuality, she would have shed more light on the scope of ii 5.
I don’t agree with the interpretation Arruzza gives of Aristotle’s criticism of the Megarian claim in Metaphysics Θ 3. According to Arruzza, the Megarian claim, which Aristotle thinks should be rejected, stipulates that “something is in potentiality before its actualization and regardless of whether the actualization can take place” (p. 26). It seems to me, though, that the Megarian claim, as stated by Aristotle, is, contrary to what Arruzza writes, that nothing is in potentiality if it is not at the same time in actuality, i.e. that potentiality and actuality are identical. That is why Aristotle presents the Megarian claim as absurd, because it makes both movement and becoming impossible: Μet. Θ, 1046 b 29-1047 a 20.
There are nine such discussions: In 1.4 she follows HS3; in 1.9-10, she follows Kirchoff and Narbonne; in 2.10-11 she takes into account the indication of HS2; in 2.21-22 she follows Igal in the construction of the phrase; in 3.5-6 she follows HS5 and the manuscript family y; in 3.12-13, the manuscript family y and Narbonne (1998); in 3.30, 32 and 33 she follows HS1 and HS2 instead of Kirchoff; in 3.40 she adopts the reading of HS2 against Kirchoff’s emendation; and in 4.12-13 she follows Kirchoff and HS2.