1 Plotinus on Intelligible Qualities

This chapter provides a commentary on Enn. 6.2.14, a text which raises some questions concerning the status of quality in Plotinus’ metaphysics. Some interpreters suggest that Plotinus here distinguishes two levels in intelligible οὐσία and that he expresses this view through the distinction between constitutive features and qualities. This distinction had been developed in the commentary tradition on Aristotle’s Categories and Plotinus focuses on it in treatises 2.6 and 6.1 when discussing sensible substance. I aim to show, instead, that Plotinus does not adapt the classification of properties to his account of intelligible being. Rather, he shows that quality is not one of the greatest genera or kinds that define the structure of the Intellect. So the greatest genera are neither accidental qualities nor constitutive features of intelligible being. Furthermore, Plotinus argues that the distinctive type of multiplicity in the Intellect cannot be expressed through the distinction between subject and property, because at the level of intelligible being all multiplicity is substantial and completely internal.

§1 Two Kinds of Qualities

The status of quality in Plotinus’ metaphysics is a matter of discussion. Plotinus seems to be wavering on this issue: more precisely, his views about the status of qualities in sensible particulars leave certain questions open. In his early treatise 2.6 (no. 17 according to the chronological order) On Substance, or on Quality, he identifies substances with intelligible beings, and qualities with their sensible images (i.e. perceptible properties) (2.6.1.7–8; 2.6.1.13–15; 2.6.1.42–49).1 So the distinction between substance and quality and that between intelligible principles and sensible properties come to coincide. Grosso modo, this stance can be traced back to Plato’s anti-essentialist views on sensible beings as qualitative wholes outlined in the Timaeus.2 Yet, in the same treatise Plotinus draws a distinction between two different kinds of perceptible qualities by opposing qualities that are constitutive or ‘completions’ of substance (ὅσαι λέγονται συμπληροῦν οὐσίας, 2.6.2.20–21) — that is, qualities that go into the making of sensible particulars and make of them what they are — and mere qualities that lie outside all substance (2.6.1.15–16; 2.6.2.20–26). The distinction between constitutive and merely accidental qualities comes from the commentary tradition on Aristotle’s Categories.3 Plotinus integrates the bipartition of qualities into his distinctive metaphysical view of causation and formal principles. Thus he claims that constitutive qualities are actually activities that come from the formal principles and essential powers (2.6.2.20–22: ἐνέργειαι […] ἀπὸ τῶν λόγων καὶ τῶν δυνάμεων τῶν οὐσιωδῶν ἰοῦσαι).4

This view raises some problems. If constitutive qualities come from the intelligible formal principles, we could infer that accidental qualities come from matter; but Plotinus is silent on this issue and, indeed, the idea that matter as such could be causally responsible for some sensible properties is problematic (Plotinus usually conceives of matter as causally inert, although this view is sometimes qualified). So the origin of mere qualities remains unexplained.5 Plotinus’ account of constitutive qualities is controversial too. The view that all sensible properties are qualities and as such are distinct from substance (i.e. from intelligible and extra-physical essential principles) appears to conflict with the distinction between constitutive and merely accidental qualities, since constitutive qualities seem to be too close to substance, so to speak, or rather internal to it: they actually make a sensible particular what it essentially or properly is. As Porphyry was to put it, ‘items constitutive of substances are substances [τὰ συμπληρωτικά … τῶν οὐσιῶν οὐσίαι]’ (Ιn Cat. 95.33).

Plotinus does not go as far as Porphyry: he does not claim that constitutive qualities are οὐσίαι. Yet in 2.6.2.21–22 he says that constitutive qualities come from formal principles or substantial powers. In the later treatise 6.1 (42) (the first section of Plotinus’ tripartite treatise On the Genera of Being) Plotinus argues that specific differentiae can only be regarded as qualities equivocally (i.e. homonymously: see Aristotle, Cat. 1.1a1–6) and that they are rather activities or λόγοι, or parts of λόγοι (see 6.1.10.20–24). Differentiae show what a thing is, even if they seem to show a qualified substance.6 Despite some minor differences, this passage is consistent with 2.6.2. Both passages suggest that the notion of ‘quality’ or ‘qualified’ can be taken in both a broad and a narrow sense.7 In a broad sense, all properties of sensible particulars are qualities (and differ, as such, from intelligible essences). In a narrow sense, however, only accidental properties can be regarded as qualities, since they are ‘outside all substance’ (2.6.2.23). Constitutive properties, instead, are not really qualities at all, but activities that come from the formal principles, and they indicate what a thing really is. This view seems to entail that constitutive qualities are essential properties of sensible particulars (and they are taken to be such in the commentary tradition on Aristotle’s Categories). Yet sometimes Plotinus rules out the idea that essence can be counted among the properties of an object: sensible particulars are not endowed with essences. What, e.g., Socrates properly is, is neither one of his properties nor a conjunction of properties, but a forming principle that is different from the whole structure of the corporeal being (see 6.3.15.24–38; 6.7.4.16–30). If this is true, no quality is essential.8 Within this framework, the status of constitutive qualities remains problematic: they can be neither essential (for sensible particulars are not endowed with essences) nor accidental (for constitutive qualities are different from merely accidental ones). So in the third part of the treatise On the Genera of Being (6.3, no. 44 according to the chronological order) Plotinus further develops the enquiry on sensible substance and stresses its non-essential character.9 He thus argues that sensible particulars should be regarded as mere conglomerations of matter and preceptible qualities (συμφόρησίς τις ποιοτήτων καὶ ὕλης: 6.3.8.20) and seems to reject the view that some qualities are constitutive ones, and hence different from merely accidental qualities. In 6.3 Plotinus conceives of sensible particulars as wholes that are made up of non-essential features that occur in matter. Sensible particulars are thus made up of non-essential components; they lack substance and are mere conglomerations with no substantial unity. This view is central to Plotinus’ critical rejection of Aristotle’s hylomorphism.10

This situation reflects an internal tension in Plotinus’ account. Either he conceives of sensible particulars as endowed with an internal structure, which corresponds to a hierarchical order among their properties (but this is too close to the notion of ‘essential property’, and according to Plotinus sensible particulars are not endowed with essences), or he conceives of sensible particulars as entirely qualitative wholes, where constitutive and extrinsic properties cannot be opposed (but this apparently jeopardizes an adequate account of sensible particulars, where some properties are more ‘important’ — i.e. more essential or explanatory — than others).

§2 Qualities and the Greatest Kinds: 6.2.14

At least one thing seems to be reasonably clear: according to Plotinus there are no qualities at the level of intelligible principles. In 2.7.3 he claims that the λόγος includes and contains all qualities, but this statement does not really entail that intelligible λόγοι are qualitative. Rather, Plotinus suggests that λόγοι contain within themselves all features that appear as qualities in bodies (see 2.6.1.13–15). Bodies are composed of all qualities plus matter, but qualities are ‘pre-contained’ in formative principles according to their distinctive mode of being, which is essential rather than qualitative (see 6.3.15.24–31).11 There is, however, a puzzling section of 6.2 (no. 43 according to the chronological order) which has drawn scholars’ attention: this section apparently suggests that Plotinus makes use of the bipartition between constitutive and accidental qualities in his account of intelligible beings and adapts it by introducing some alterations. 6.2 is the second part of Plotinus’ tripartite treatise On the Genera of Being, devoted to the intelligible genera which constitute the basic structure of the Intellect: these are being, motion, rest, sameness, and otherness, as Plotinus argues by...