Plotinus has two treatises on the central notions of ancient ethics, named by Porphyry On Virtues (peri aretôn) and On Happiness (peri eudaimonias). Both are found in Ennead 1 but they are not chronologically related. The study on virtues (Enn. 1.2) belongs to the earlier half of the treatises (no. 19) and was written between 253 and 264, while the treatise on happiness (Enn. 1.4) dates from the last year and a half in Plotinus’ life. Scholars have debated about whether Plotinus’ reflections on virtue and happiness amount to a consistent ethics that has something to offer for everyday life.1 I shall return to this question in the concluding section after considering the two treatises. It can be noted already that Porphyry’s title On Virtues (peri aretôn)2 could lead us to expect a comprehensive and practical account of virtue in Enn. 1.2 but no detailed guidelines are given for particular situations. This might suggest that ethics is an entirely theoretical affair for Plotinus. However, Plotinus’ focus is narrower, and it would be premature to exclude practical concerns for a Plotinian virtuous person because of the scope of the treatise.

An enduring interest in categories (katēgoriai),1 and in Aristotle’s Categories in particular, has led readers since antiquity to study the treatise which Porphyry entitled On the Genera of Being (6.1–3).2 Ancient and modern readers broadly agree that: (1) Plotinus understands his own subject matter to be ‘the kinds of things that exist’ (peri tōn genōn tou ontos); (2) the treatise displays the result of a deep and substantial engagement with Aristotle’s Categories; and (3) Plotinus raises important and substantive puzzles (aporiai) about what is said in the Categories.3 Beyond this, plausible interpretations diverge. On one view, Plotinus deploys the resources of earlier Platonist critics to challenge the Categories’ ontological prioritization of particular substance, especially as it is treated by earlier Aristotelian commentators.4 On an alternative reading, Plotinus ‘purifies’ Aristotelian ontology in order to sketch a new taxonomy of the sensible world, complementing his own account of the intelligible world and clearing a trail for Porphyry’s integration of Aristotle into a new Platonist curriculum.5

PEQ: Should we retain the decimal numbering of headings according to chapter number?

It can be difficult to get a handle on Plotinus’ conception of Nature (phusis), not least because of the numerous other connections in which Plotinus employs the Greek term phusis.1 Let us put the other uses of the term aside for now and focus on what I shall henceforth refer to as ‘Universal Nature’ or simply ‘Nature’.2 Universal Nature, for Plotinus, is no mere abstraction but a determinate entity that is causally efficacious in the sensible world in a number of ways.

The Greek word empsukhos (‘ensouled’) was used in ordinary language to describe something as alive.1 Philosophers from all major schools specified this linguistically marked connection between soul and life by postulating or arguing that the soul is the principle of life.2 The soul can be understood to be so in three ways. All life-constituting activities of a living being are activities of the soul, or they are activities of the composite of body and soul, or some are activities of the soul and others of the composite. Plotinus defends the first option.3

With Plotinus, Neoplatonism was inaugurated with the positing of a radical transcendence: the first principle, the One, or the Good,1 is beyond the essence, epekeina tēs ousias. In book 6 of the Republic, Plato already designated the Good as beyond essence, which it surpasses in seniority and in power, ‘epekeina tēs ousias presbeiai kai dunamei huperekhontos’ (509b9–10), but whereas in Plato this formula is found only once, and its interpretation is, moreover, disputed,2 it is recurrent and systematized in Plotinus.3 It also allows a series of variations; beyond essence, the One-Good is also ‘beyond thought’, ‘beyond knowledge’, ‘beyond life’, and, again, ‘beyond act’.4

Knowledge in Plotinus is a complex yet unified phenomenon. His most general term for it, gnōsis (‘cognition’), covers a broad range of phenomena from sense-perception (aisthēsis) via discursive reasoning (dianoia) to intuitive intellectual insight (noēsis).1 The general framework of his epistemology is unambiguously Platonic. Plotinus shares Plato’s conviction, prominently voiced in the Timaeus, that only unchanging intelligible Being admits of real understanding, whereas perception of sensibles only yields opinion or belief.

The epigraph that opens this chapter quotes the statement with which Proclus, one of the last heads of the Platonic Academy in Athens, opens his Platonic Theology, a six-volume elaboration of the metaphysics of the divine as found in Plato’s dialogues. According to Proclus, the history of philosophy is a ‘golden chain’ of Platonic succession, which starts with the Gods, Pythagoras, and Plato, and then, after a period of retreat, finds in Plotinus a ‘coming back into the light’.1

According to Plato’s Timaeus, a benevolent divine craftsman creates the cosmos, guided by his intellect’s reasoning and his ‘forethought’ or ‘providence’ (pronoia, Tim. 30b) about how to make it as good as possible. Similarly, in Laws 10, a wise god is said to exercise oversight over the cosmos, and to have devised laws of fate that promote virtue by assigning souls to positions in the cosmos according to their deserts. These and other Platonic texts were important sources for later Platonist theories of providence, according to which beneficent divine thought ensures the best possible arrangement and management of the cosmos.

Part I addressed counting as a means of interrogating the relationship between poetic content (the ‘stuff’ that a poem contains) and the space that is needed to express it. There I demonstrated that counting had an important role to play in poetic criticism of the Hellenistic period and that later poets were aware of this, incorporating and developing counting criticism in their own programmatic poetic statements. In early mathematical education, after counting there came more complex operations: multiplication, but also calculations that in modern mathematical notation would be written as equations and solved algebraically. These mathematical procedures today form part of arithmetic. The focus of Part II is thus on how the ‘stuff’ of poetry is expressed and arranged so as to require an arithmetical interpretation and solution.

Saying things takes time; writing things takes up lines. There is always a connection between the length of a verbal utterance (in time when spoken and in space when written) and what it seeks to describe. There is a certain connection between form and content. In the terms I will be using throughout this book, it is a relationship (as yet undefined) between poetic extent and poetic content. How was this relationship perceived in Graeco-Roman antiquity?