Plutarch is well known as a generally even-tempered expositor of the great tapestry of Greek history, literature, and philosophy, and a benign counselor on questions of ethical conduct and social mores, but there is another side to him, that of the accomplished polemicist, primarily in the area of philosophy, but also concerning his predecessors in the craft of history, and on occasion the poets as well. In all of Plutarch’s polemics, we can discern common threads. While historians (especially Herodotus) and poets are criticized primarily for their flawed socioethical views, the Stoics, Epicureans, and even Plutarch’s predecessors in the Platonic tradition have the inconsistencies in their positions relentlessly skewered, and the most absurd consequences of their misguided arguments teased out. This essay surveys a selection of Plutarch’s critiques of previous historians, then casts a brief glance at his censure of the poets, before turning to an examination of his polemics against rival philosophical schools, and lastly rival views within the Platonist tradition.

The chapters in this book are all readings, or interpretations, of key characters and episodes in the Divine Comedy where it can be shown that what is at stake is a kind of faith. What has been argued is that reading itself is an act of faith, a willingness to trust not only in the individual human author or narrator, but in the larger story in which all truthful, good faith narratives somehow fit. A different faith, like a superseded hypothesis in science, is another way of approaching a single truth and it can be read, charitably, as such.

Numenius (second century AD), the only witty Platonist after Plato himself, memorably described Plato as ‘Moses talking Attic’. He did not mean thereby to rate Eastern wisdom more highly than Platonic philosophy, as is sometimes suggested, but to recognise in the words ‘I AM THAT I AM’, spoken to Moses by the God of the Hebrews, an anticipation, unique in Eastern lore, of the conception Numenius championed of the Platonic first principle One or Good as Being itself. This paper proposes that his further exploration of that idea shows him to have construed the Timaeus account of such being as an eternal present, or in Boethius’s words ‘the complete possession all at once of an infinite life’, not as timelessness (the Timaeus interpretation advocated by Richard Sorabji). It is argued that this was both a correct interpretation of Plato’s text, and one shared in much subsequent ancient and medieval philosophy, including Plotinus, Augustine, and Aquinas. From our own human perspective, a present tense without past or future connections might be considered ‘a kind of logical torso’, a defective remnant of ordinary time. For Plato that human conception of present time is itself a mere image of eternity.

What did Plato mean when in Timaeus he characterised his account of the created world as an εἰκὼς μῦθος? The phrase is typically translated ‘a probable story’, ‘a likely tale’. Connotations that modern empiricist philosophy of science might attach to those expressions are misleading. Careful attention to the two terms Plato uses, and their resonances in previous Greek literature and thought, suggests instead the strikingly oxymoronic: ‘a rational/reasonable myth’. This is not, however, the reasonableness of deduction or of inference to the best explanation, but of the practical reasoning in which a supremely good designer would probably engage, assuming that he wanted to make his product as like himself as possible, but from materials with their own properties not of his making. Practical wisdom cannot aspire to the same standards of rigour as theoretical wisdom can. It can attempt only the most reasonable option given such constraints – as could any account of why that choice was made. Hence the importance of the Timaeus’ initial reminder of Socrates’ construction of a political order (witness the Republic), and its address to a company competent in politics as well as mathematics, interested no less in κόσμος as political order than in cosmology.

This chapter offers an account of the inspiration for their active advocacy of political, social, and educational reform that three key figures of the British nineteenth century found in Plato: John Stuart Mill, George Grote (author of the classic three-volume study Plato of 1865), and Benjamin Jowett (whose translation of the entire Platonic corpus of 1871 was to be hugely influential). For both Mill and Grote, the importance of the probing Socratic method portrayed in the dialogues was paramount. Grote contrasted it with the tyranny exercised over the dissenting individual by the conformism of society at large: what he called King Nomos, with his eye particularly on the Great Speech Plato puts in Protagoras’s mouth in the Protagoras. To his mind, the Republic represented a sad betrayal of the Socratic spirit. It was Jowett who was chiefly responsible for making that dialogue’s moral idealism central to the education Oxford provided for the nation’s future elite, and whose endorsement of its radical proposals for equality for women in education and in politics is particularly notable.

I examine Aristotle’s reasons in DA I.3 for rejecting the claim that understanding (nous) is a magnitude (megethos), an idea Aristotle associates most explicitly with Plato, who describes nous as a self-moving circle in the Timaeus. Aristotle shows that his definition of soul, on which soul is not a magnitude or body of any kind, can explain perception, thought, and motion better than his predecessor’s materialist accounts. But unlike perception and motion, nous is not actualized through the body nor does it have a bodily organ, which makes nous a very different kind of soul capacity. Earlier thinkers, including Plato, already maintain that nous does not have a bodily organ, but they cannot explain how nous could operate or be a mover without being some sort of body itself. Even in the Timaeus, nous is described as being a kind of magnitude. But if nous were a magnitude of any kind, Aristotle claims it would not be able to think or reason. There is something about being a magnitude qua magnitude that makes reason impossible. His critique of Plato in I.3 prepares the way for his account of nous in DA III.4.

Emphasis on the ‘craftsmanlike’ character of creation in the Timaeus can give the impression that the cosmos is no more an ‘animal’ than Dr Frankenstein’s monster. But Middle Platonists took more seriously the biological implications of the claim that the god is the world’s father as well as its maker, implanting a soul in matter which (as in all animals) brings the cosmos to maturity through its own creative agency. Entailments of the view are that the world soul is first and foremost the ‘nutritive’ soul of the cosmos and that the soul must be a structural feature of the cosmic body rather than a distinct substance.

This chapter discusses the use of technê to characterize the creator god in Plato’s Timaeus. Timaeus explains how a divine craftsman, the Demiurge, made the whole cosmos as a living being. He created the heavenly bodies, but left the creation of human and other mortal beings to these ‘lesser’ gods. But if the Demiurge was the best of all craftsmen, seeking to make the finest cosmos possible, why did he not make the mortal beings too? Having outlined Plato’s conception of craft, Johansen explains how this problem, which he calls the ‘technodicy’, arises for Timaeus, contrasting it with the classical theodicy. The Demiurge’s creation is limited by his craft. Timaeus therefore assigns another craft to the lesser gods to produce mortal beings. However, even this craft prevents the lesser gods from directly producing non-human animals, and so the problem is reiterated. The issue is sought to be resolved by making humans themselves responsible for their own reincarnation as lower animals. Timaeus’ position is comparable to the view in Laws X: the lesser gods, consistent with their role as craftsmen, have overall responsibility for the organization of lower kinds of living being, without causing any particular beings to belong to particular kinds.

Adapting certain features of Empedoclean daimonology, Plato formulated a more rigorous theory of daimonification through virtue. He daimonified the soldiers of his ideal republic for their courage, and daimonified rulers (“guardians”) for their wisdom. In his Cratylus, Plato vouched for the daimonification of all people who were noble and wise. Plato’s Timaeus introduced the ultimate democratic principle of daimonification by identifying one’s guardian daimon with humanity’s higher consciousness (or nous).

In his commentary on Nicomachus’ Introduction to Arithmetic, John Philoponus explains the role that mathematics, and hence harmonics, play in Platonic philosophy, as redefined by the Neoplatonists. There are two main issues regarding harmonics. The first issue: harmonics is one of the mathematical sciences that lead to the knowledge of divine and absolutely immaterial entities; but harmonics also concerns other mathematical disciplines, because there is an astronomical harmony, that is, the harmony of the revolution of the stars, and there is a geometric harmony, that is, the cube, one of the Platonic solids that are the constitutive elements of the physical world as a geometric model of equality. The second issue: there exists a harmonic proportion, already known to the Pythagoreans, Plato and Aristotle. Both these aspects in Philoponus’ study of harmonics have a common denominator, namely the fact that, as Plato teaches in the Timaeus, the universe, its soul and human souls have a numerical structure based on the relationship between two principles, that is, equality and inequality. But harmonics is precisely the mathematical science of relationship. Therefore, harmonics has a privileged place in the Neoplatonic philosophical system, as Philoponus’ commentary worthily testifies.

By exploring three issues which connect music with Platonic cosmology, I argue that, according to Plutarch, this connection was at the same time very important and severely limited. (1) In several passages of De animae procreatione, Plutarch compares the demiurge to a musician. These comparisons suggest a certain degree of similarity, but also a significant degree of difference between the two and, accordingly, between cosmic harmony and music. (2) Similarly, Plutarch’s reception of the notion of ‘music of the spheres’, as it emerges from a discussion in Quaestiones convivales, confirms the connection between music and the cosmos only to a limited extent. What the answers of the discussion have in common is that they all warn against excessive appreciation of music. (3) Finally, in Amatorius and De Pythiae oraculis, Plutarch distances musical experience from divine inspiration (enthousiasmos). In general, this persistent combination of importance and limitedness can be explained by Plutarch’s interpretation of Plato’s Timaeus.

Chapter four focuses on Avicenna's endeavour in his famous Canon of Medicine to reassert the epistemic authority of philosophy by restoring the proper boundaries of medicine, which Galen had especially obscured through his engagements with Plato's Timaeus. I maintain that Avicenna, a student of Aristotle, formulates this polemic in response to the threat that Galen's defence of the dialogue's brain centred psycho-physiology posed to the credibility of Aristotelian cardiocentrism, which identified the heart as the source of sensation. This study examines how Avicenna appeals to the restrictive epistemic hierarchies of his intellectual milieu, which limit doctors to subjects only relevant to the production or preservation of bodily health, to delegitimize Galen's contributions to natural philosophy. The rhetorical, as opposed to normalizing, force of the disciplinary prescriptions that he levels at Galen in the Canon of Medicine will become clear from my analysis of Avicenna's discussions of the hegemonic organ and pleasure in his philosophical works, where he transgresses his own 'laws' when disputing or even adopting TImaean positions on these issues.

Reflecting on the subjects from Plato's Timaeus at the centre of the disciplinary rivalry explored in the preceding chapters, I conclude that mind-body problems -- questions treating the extent to which psychic and 'mental' processes are separable from the corporeal realm -- provoked the most debate. My contention is that Galen's interpretation of a close link between the body and soul in the dialogue allowed himself and his sympathizers to give doctors a stake in psychological knowledge and trouble the distribution of value based on the corporeal-incorporeal dichotomy, which privileged philosophers. Therefore, the restrictive disciplinary laws imposed on doctors by Avicenna and Maimonides are a strategy to reclaim philosophy's hegemony on the soul and superior epistemic standing. While my study had divided Galen's successors into supporters and opponents of his project, I maintain that each Arabic actor tries to overwrite Galen's expertise with their own. Finally, I consider how my examination of the discursive reimagining of medicine can provide a longue durée perspective on modern reconceptualizations of the field, such as disputes about the relevance of the Medical Humanities.

The third chapter focuses on the Iranian doctor Abū Bakr al-Rāzī (sometimes called the 'Arab Galen'), who was attacked by later Islamicate thinkers for his disciplinary overreach, and his bid to replace Galenism with his more theologically informed system of medicine and philosophy. In particular, it argues that al-Rāzī seeks to weaken the epistemic authority of Galenism through his critiques of Galen’s explanations of certain ideas from Plato’s Timaeus. I first consider the Middle Platonic and Neoplatonic sources on which al-Rāzī may have drawn to elaborate his 'anti-Platonism' – his Platonism in response to Galen's Platonism. Turning finally to the Doubts about Galen, I demonstrate that al-Rāzī attacks Galen on the subjects of creation, pleasure, and the soul for neglecting God's role in the cosmos in his interpretations of the Timaeus. In reformulating the boundaries of medicine to include theological knowledge, which belonged in ancient epistemological schemes to metaphysics, al-Rāzī, I conclude, promotes the doctor-metaphysician in opposition to Galen’s more limited philosopher-doctor as the most reliable investigator of the cosmos.

The introduction asserts that the different causal, spatial, and comparative relations in Plato's Timaeus generated a model of knowledge that denies a strict separation between the disciplines. I contrast the dialogue's epistemic vision with the prevailing hierarchies of knowledge developed by ancient thinkers, including Plato himself, which ranks medicine below philosophy because it is a technē ('art'), deals with the body, and its practitioners were often enslaved or freedpersons. I argue that Galen's expansive refiguring of medicine's boundaries -- his 'boundary work' -- is part of a tactic to improve his profession's credibility and his own authority. After outlining my approach to science as a discursive practice, I consider how Galen's philosophical training enabled him to exploit the epistemic possibilities of the Timaeus, which seems to recognize that knowledge can be divided and bounded differently by each knower. I conclude by proposing that Galen’s own role in interfacing Arabic readers with the dialogue called for Arabic doctors and philosophers to reevaluate their own categories and taxonomies of knowledge, which had been shaped by late-antique epistemologies.

The second chapter studies the efforts of the Christian Ḥunayn ibn Isḥāq, whose workshop in ʿAbbāsid Baghdad translated the Galenic sources considered in this book, to enhance the respectability of the specialism of ophthalmology in his Ten Treatises on the Eye. I show that, even more so than medicine, ophthalmology was at a disadvantage in its pursuit for epistemic authority because Galen himself had attacked the sub-field as an exemplar of the worrying tendency among doctors in Rome and other cities towards specialization, which threatened the unity of the discipline and the health of patients. Concerned with his own intellectual status at court, Ḥunayn, I argue, subversively uses Galen's explanation of the Timaeus' description of the eyes' service to the rational soul to give ophthalmologists a stake in medico-philosophical controversies relating to sensation. I also expose how Ḥunayn modifies Galen’s interpretation of Plato’s teleological ocular anatomy and visual theory in order to privilege the eye over all other organs as a window to cosmic knowledge.