Ennead II.5 is a crucial text for understanding Plotinus’ use of the terminology of potentiality (τὸ δυνάμει), actuality (τὸ ἐνεργείᾳ), active power (δύναμις) and activity (ἐνέργεια). This treatise begins with an exposition of Aristotelian theses concerning these terms, unfolds in criticising the Peripatetic schemes, and comes to Plotinus’ re- interpretation: potentiality is excluded from intelligible being on the one side and actuality from sensible matter on the other side; actuality and activity are considered identical in the intelligible world, but are to be differentiated in the sensible world: the one is the compound of matter and form, the other the immanent form. The anti-Aristotelian conclusions are two. While sensible reality, according to Aristotle, involves continuity of change based on the actualisation of proximate matter, Plotinus breaks this continuity by defining matter only as prime matter which can never be actualised. While Aristotle mentions in De Anima II.5 a certain potentiality in the soul, Plotinus argues that it is rather active power than passive potentiality.
This text is difficult due to Plotinus’ dense style. Based on the inclusion of important research in recent years, such as that of Narbonne1 and Kalligas2, and on the author’s own contributions, Cinzia Arruzza’s new English translation is an improvement compared with the older ones. And her clear commentary not only sheds light upon the difficult text, but also offers innovative investigation of and answers to the controversial problems in this treatise.
In some cases, Arruzza’s reading and translation of the text differ from that of Armstrong, but reflect the current understanding of Plotinian scholarship. In 1.4 for example, Arruzza adopts the emendation suggested by Henry- Schwyzer 33 and Narbonne4: εἴ τί ἐστιν ἐνεργείᾳ, τοῦτο καὶ ἐνέργεια (‘is what is in actuality also activity?’), not following Henry-Schwyzer 1-2 and Armstrong: εἴ τί ἐστιν ἐνέργεια, τοῦτο καὶ ἐνεργείᾳ. Her references to 1.5-6 and 3.34-5 support this reading (pp. 63-4).
1.17-20: Δεῖ τοίνυν τὸ δυνάμει τι ὂν ἄλλο ἤδη . . . δυνάμει λέγεσθαι. In contrast to Armstrong (‘already potentially something else’) and Harder (‘welches potentiell etwas anderes ist’) who construed τι ὂν ἄλλο ἤδη with δυνάμει, the new generation of translators regard τι ὂν ἄλλο ἤδη as a circumstantial participle to τὸ δυνάμει: ‘a potential being must be called potential, while already being something else in actuality’ (Arruzza), ‘tout en étant déjà en acte quelque autre chose’ (Narbonne). ‘In actuality’ and ‘en acte’ here are the interpretation of the translators. Plotinus here exposes Aristotle’s definition of potential being. To say that potential being is from another point of view ‘already in actuality’ is sound according to Aristotle. But to say that potential being is already potentially something else is not so usual: already (ἤδη) adds nothing in this translation. The fact that Harder has not rendered ἤδη suggests this. Arruzza’s argument based on this word ἤδη is convincing (p. 71). As evidence in support of her understanding, one can refer to 1.15 ἤδη παρῆν as well. ‘Already’ here is connected with ‘presence’, that is to say ‘actuality’, not with ‘potentiality’.
In 3.13, Arruzza follows the manuscript family y and Narbonne in reading ἐροῦμεν instead of ἐροῦσιν in Henry- Schwyzer and Armstrong. Contextualized, this reading is better. Since intelligible matter is acknowledged by Plotinus himself (II.4), the question raised here should be: what will we say, what will we refute, if someone were to infer potentiality in the intelligible world from our acceptance of intelligible matter? And the following lines 3.14-5 are Plotinus’ own answer.
In 3.15, Ἢ οὔ· εἶδος γὰρ ἦν αὐτῆς, Arruzza rightly translates ἦν ‘we did say’, against Armstrong who treated the imperfect as unreality ‘would be’. It is not counter-factual that the intelligible form is the form of intelligible matter, but a fact that Plotinus has recognized as true. The imperfect here is a philosophical imperfect. This use of imperfect is not rare in Plotinus (cf. III.2.2.9).
Arruzza’s commentary is also praiseworthy. First, she enriches the citation of ancient sources beyond the range given in the previous commentaries. For example, in adopting Corrigan’s 1996 research,5 she refers Plotinus’ description of matter as πάντα δυνάμει (4.4) to Alexander of Aphrodisias, On Aristotle’s Metaphysics 292.25 (pp. 136-7, 158). This is important information that clarifies the background of Plotinus’ writings.
Secondly, she introduces several thorny issues that are discussed in the academic debates and gives her own comments on and solutions to these. For example, it was noticed by scholars that the description of matter in II.5, III.6 and I.8, and that in IV.8, were inconsistent. In II.5, III.6 and I.8, matter is said to be ‘separated’, ‘non-mixed’ with form; but in IV.8.6.18-23, Plotinus speaks of the continuity of causality, in which matter should not be isolated from the soul. This passage is very controversial and has prompted a variety of interpretations.6 After reporting the solutions of other scholars, Arruzza explains this inconsistency by the various contexts: in IV.8, from the viewpoint of the soul, forms bestows something on matter, but in II.5, III.6, I.8, from the viewpoint of the matter, participation in form is impossible because of its own incapacity (pp. 159-62). This interpretation is subtle.
Thirdly, some investigation in the commentary is innovative and merits more attention and discussion. In interpreting 1.17-21, Arruzza offers a different understanding than that of Narbonne in his commentary. According to Narbonne, Plotinus here exposes the Aristotelian distinction between qualitative change (1.18, μένον μετὰ τοῦ ἐκεῖνο ποιεῖν) and substantial change (1.19, παρέχον αὐτὸ ἐκείνω ὃ δύναται φθαρὲν αὐτό), and illustrates qualitative change with the example of the bronze becoming a statue (1.20), and substantial change with the example of water becoming bronze and air becoming fire.7 Arruzza considers the transformation of bronze into a statue a particular kind of substantial change or generation. She bases this interpretation on Physics 7.246a 1-4, where change of shape (e.g. transformation of bronze into a statue) is to be distinguished from qualitative change or alteration. Hence, the distinction made in 1.17-21 is, according to Arruzza, between two different kinds of substantial change in the Aristotelian tradition and not between qualitative change and substantial change (pp. 72-8).
Since the three passages, 1.17-21, 2.12-5 and 3.4-8, are correlative, the divergence of interpretation with 1.17-21 leads to different understanding concerning 2.12-5 and 3.4-8 as well. Since Arruzza holds that the change of bronze into statue is a substantial change, she concludes that Plotinus in 2.12-5 only means that there is no actualisation of what is potential in substantial change. One can not infer, according to Arruzza, that Plotinus denies the actualisation of what is potential in every kind of change (pp. 91-5). On the contrary, Narbonne holds that every kind of change in the sensible world can be understood along the lines of the change of bronze becoming statue, and Plotinus’ critique concerns every kind of change without exception.8 This divergence in interpretation already touches what is significant to the understanding of Ennead II.5. Arruzza has incisively grasped Plotinus’ main intentions in this treatise and has noticed the correlation between this treatise II.5  and the following two treatises: III.6  and IV.3 . Plotinus’ critique in II.5 is, according to Arruzza, directed to Aristotelian hylomorphism (pp. 41, 141); and this point will be developed in III.6, where matter is compared to a mirror without affection, and the sensible object to the reflection in the mirror that lacks its reality. Meanwhile, she has also noticed some subtle problems that are not as evident as the main topics.
First, she mentions the tension between Plotinus’ two attitudes: he speaks of potential being in the case of sensible realities (1.6-7), but according to II.5 prime matter is not itself ever actualised as it takes on a succession of different forms (pp. 64-5). Furthermore, concerning the evaluation of sensible beings, one can ask, if Plotinus’ rejection of Aristotelian hylomorphism is really consistent with his own interpretation of sensible compound as actuality and immanent form as activity in II.5.2. If the rejection of hylomorphism is thorough, there is no room to interpret the sensible compound as actuality.
Secondly, Arruzza has called attention to the fact that Plotinus has not addressed in II.5 all aspects of the terminology of potentiality, actuality, and so on (pp. 41-2). While Plotinus in II.5 rejects the use of the term ‘potentiality’ (τὸ δυνάμει) in the case of intelligible being, he uses it in IV.8.3.14-6. The theme of intelligible potentiality has not escaped the notice of the scholars.9
These two difficulties, the inconsistency inside II.5 and between II.5 and other treatises concerning the evaluation of sensible being and the intelligible potentiality, are not discussed in detail in the commentary, but belong among the most challenging issues in the interpretation of the Enneads.
1. Jean-Marc Narbonne, Traité 25 (II, 5) (Paris, Éditions du Cerf, 1998).
2. Paul Kalligas, The Enneads of Plotinus. A Commentary, Volume I. Translated by E. K. Fowden and N. Pilavachi (Princeton and Oxford, Princeton University Press, 2014).
3. Addenda and Corrigenda in Paul Henry and Hans-Rudolf Schwyzer, Plotini Opera (Paris; Bruxelles, 1951-1973).
4. Jean-Marc Narbonne, Traité 25 (II, 5) (Paris, Éditions du Cerf, 1998), 39.
5. Kevin Corrigan, Plotinus’ Theory of Matter-Evil and the Question of Substance in Plato, Aristotle, and Alexander of Aphrodisias (Leuven, Peeters, 1996).
6. See the five interpretations listed in Plotin. Traités 1-6, traductions sous la direction de Luc Brisson et Jean-François Pradeau (Paris, GF Flammarion, 2002), 266.
7. Jean-Marc Narbonne, Traité 25 (II, 5), (Paris, Éditions du Cerf, 1998), 26, 79.
8. Jean-Marc Narbonne, Traité 25 (II, 5), (Paris, Éditions du Cerf, 1998), 79, 87.
9. Richard Dufour, ‘Actuality and Potentiality in Plotinus’ View of the Intelligible Universe’, Journal of Neoplatonic Studies 9 (2004), 193-218.