When Socrates has established as rulers of the best political order those who are legitimately lovers of learning and who are not counterfeit philosophers, and when he has declared them worthy to be spectators of the universals – and the affairs which are governed by them will come to resemble those universals – he postulates that most of all they will understand this very last object of learning. Since his companions have asked for a discussion from him as to what this means, and what the final one of all the objects of learning hints at,18 he says that they have already heard this many times before, namely that this is the Good, which all things desire. And it is not possible to say where one should turn one’s thinking (dianoia),19 if one should neglect this axiom. He announces that he will show what exactly the good is.

Despite the title of Essay 12 (‘On the Cave in the Seventh Book of the Republic’), the text which survives deals not only, and in fact not primarily, with the famous image of the Cave, but also with the image which precedes it in the Republic, the Divided Line. Due to a lacuna in our essay, of uncertain length but of at least one entire folio, a large part of Proclus’ discussion of the Cave is lost to us. Proportionately, therefore, we have more remaining to us of the discussion of the Divided Line. By the nature of the passages which Proclus analyses here, there is some overlap with Essay 11 (in relation to the Good), and Essay 10 (in relation to the ascent through the distinct ontological levels).

The chapter focuses on the central role Galen ascribes to his own first-person ethical and emotional experience in the construction and defense of his ethical theory and therapy of the emotions. I argue that by appreciating the complex role that Galen’s autobiographical episodes play in his moral works, we can better understand both the theory he proposes and his conception of the role that first-person experience and philosophical argument play in moral education and judgment. As I show, Galen’s emphasis on his own first-person ethical experience not only fits well with his more general epistemological view of the importance of experience in the acquisition of scientific knowledge, but also makes a substantive contribution to his account of moral education and emotional therapy.

The Tenth Book is divided into three principal topics. The first of these is directed towards a critique of poetry on the grounds that it is mimetic, but not educative of souls. The second establishes the immortality of the soul and reveals its kinship with the divine. The third provides the myth itself, which exhibits providence as a whole, both daemonic and divine, which governs souls both descending into becoming and transcending becoming, and the multi-form ways of each. These being the three subjects, it is clear that the first proposes to separate us from material images (eidôlon) and to lead us up from the illusions (phantasia) of false learning, because these draw us down to the very last of existent things, which are in fact partial (merikos) and imitative of existent things, but do not truly exist themselves, and [to lead us up] from what is simply and entirely a fictive life.

The chapter focuses on the methodological debate between Empiricist and Rationalist schools of medicine, as portrayed in Galen’s early treatise On Medical Experience (Med.Exp.). This dense and philosophically-sophisticated text, preserved for the most part only in an Arabic translation, supposedly presents the substance of a dispute, witnessed by the young Galen, between his Rationalist teacher Pelops and an Empiricist opponent, about the respective roles of experience and reason in medicine. Analysing the arguments on both sides, in particular as they concern the question of inductive generalisation and the nature and validity of the empirical procedure known as epilogimos, the chapter shows how Galen’s presentation of a sequence of responses and counter-responses between the two protagonists serves to prefigure his own complex and hugely influential synthesis of the empirical and rationalist procedures in his own mature methodology.

This chapter examines the change in the fortunes of Galen that began to occur at the time when Aristotle was beginning to be recognised as the supreme ancient authority in the Arabic world, eventually eclipsing the reputation of Galen, at least as a philosopher. It shows how Galen’s pre-eminence as a philosophical authority was gradually undermined by a sequence of commentators on his great work of scientific method, On Demonstration. Its main focus is on al-Rāzī’s Doubts about Galen composed in order to bolster Galen’s reputation when it was beginning to be challenged, notably by al-Fārābī. Central to al-Rāzī’s (partial) defence is an endorsement of Galen’s strong, Aristotelian notion of a demonstrative empirical science, as well as of his rejection of mere induction and argument from example as appropriate means of arriving at the requisite axiomatic principles. However, al-Rāzī takes Galen to task for failing to observe his own distinctions, and for taking insufficient care to ground his own fundamental assumptions. Al-Rāzī then applies his modified Galenian method to theological arguments, notably design-arguments, and in order to reject supposedly fallacious materialists’ arguments against creation. The article then turns to al-Fārābī, who in contrast directly attacks Galen’s inferential methods to support contrary, Aristotelian, positions.

Socrates dealt with two arguments through which he supposes that the sameness of education and virtue for men and women is rendered unstable.98 One argument leads the doctrine to something contrary to received opinion (adoxos)99 (for, attempts to go from things that are contrary to received opinions have a capacity to refute (anatreptikos), while those that go from received opinions are persuasive (pithanos) relative to the propositions that are under examination). The other argument proceeds from what was agreed upon – [an assumption] through which he showed what justice is and arranged the entire political order.100

The General Introduction to volume 1 in this series provides an overview of Proclus’ Republic Commentary.1 We discussed the place of Plato’s Republic within the Neoplatonist curriculum and defended the conclusion that, while Proclus’ Republic Commentary is different in character from his (incomplete) line-by-line commentaries on Alcibiades I, Parmenides, and Timaeus, it is not merely a grab bag of disparate materials that is unified only by having the Republic as their subject matter.2 The seventeen essays that make up the Republic Commentary do cover the dialogue from beginning to end. The essays also differ from one another in character and tone. Some are expressly said to have been composed for one purpose (e.g. Essay 1 arises from a class on the Republic), while others were for special occasions. As we noted in volume I, Essay 6 reflects a lecture celebrating Plato’s birthday.

If it is necessary that we too should speak about the Cave and all the things outside the Cave and their resemblance (homoiotês) to reality (ta pragmata), let us first discuss how Plato himself divided all things in the cutting up of the Line (Rep. VI 509d–511e5).17 In those [divisions] as well he makes the things inside the Cave represent the objects of opinion (doxasta), and makes the things outside the Cave represent the objects of understanding (gnôsta). It is for this reason too that, in addition to the division itself, when he has completed it in the sixth book (VI 511d6, ff.), he immediately adapted this image at the very beginning of the seventh (VII 514a1, ff.)

In Essay 11 Proclus discusses one of the most memorable sections of the Republic: the analogy between the Sun and the Good. His response to this challenging portion of the text is conceptually rich and subtle. The essay builds on the definitions developed in Essay 10 to explore the sense in which the Good can be understood when it is fundamentally unlike other objects of understanding. Essay 11 is also, by its nature, related to Essay 12, on the Cave and the Divided Line. Essay 12, however, makes a fresh start and is pitched in general at a more introductory level, as an overview of Platonic education as a whole.

The first step in Proclus’ discussion is establishing three different senses of ‘the good’ (to agathon) in Plato’s teaching on the subject. The first of these is ‘the good in us’ (to en hêmin agathon (269.16)), which is neither pleasure nor intellect, and with which he says that Socrates begins in the present passage of the Republic.

The chapter discusses two texts designed to throw into sharp relief Galen’s methods of solving natural and dialectical problems. The first comes from the treatise The Mixtures and Powers of Simple Drugs (SMT), and deals with the power and nature of olive oil. Galen castigates one Archidamus for having arrived at a mistaken account of oil’s nature, because he has generalised from a limited set of observations of questionable relevance. In contrast, Galen proposes an orderly course of inquiry, which starts from the complete account of the oil’s observable attributes and proceeds towards causal investigation by means of their empirically testable ‘differentiations’. The second text is Thrasybulus, subtitled Whether Hygiene Belongs to Medicine or Gymnastics (Thras.), and the chater shows how Galen sets about answering that question in a quasi-dialectical manner. The first step is the discovery of an agreed starting-point, consisting of a relevant and non-question-begging description of the point at issue. This is followed by further conceptual clarification of the agreed description, which, as the chapter argues, plays a similar role in the dialectical dispute as ‘differentiation’ of observed attributes in the former case.

How Socrates in the Republic arranged the account concerning the virtues, after he isolated both the political classes and the parts of the soul, is itself something that we might learn once we have first sought for ourselves an answer to this question: ‘What is the distinctive feature of every virtue?’ I do not use the word ‘virtue’ homonymously in the sense in which it is customarily applied even to things that are lifeless, as when one talks about the virtue of an implement or some such thing, but I mean instead when the term is used strictly.22 In this sense we will inevitably be speaking about something that relates to its vital character and the way that it perfects its life, since it is the cause of things going well for those in which it is present rather than of their existence.

Galen insists that genuine epistêmê, in the Aristotelian sense of securely-founded scientific understanding, is available to the serious medical investigator. The foundations consist in propositions that are evidently true, and hence require no further support. These come in two types: those evident to the senses and those evident to reason, and these are ex heautôn pista, self-crediting, intrinsically trustworthy. On the basis of such propositions the diligent inquirer can erect a firmly-founded structure of practical knowledge, a technê, but one which is, none the less, in a genuine sense demonstration. In this chapter I re-examine what Galen says about a number of inter-related key issues: What is the ‘orderly method’ of discovery which Galen regularly commends, and berates his opponents for failing to adhere to? What supplies the ‘context of justification’ for such a firmly-founded science, and how does this relate to Galen’s oft-repeated affirmation of the necessity for empirical testing, peira? And finally, and relatedly, what specific role in all of this is played by what he calls ‘differentiated experience’, peira diorismenê?

In the fifth book of the Republic, wishing to understand what the difference is between philosophers and lovers of opinion (philodoxos), [Plato] concludes by showing that while philosophers embrace understanding (gnôsis) of universals (ta katholou), lovers of opinion [embrace understanding] of particulars (merika). For [he says that] while the [lovers of opinion] only desire to learn the many beautifuls,19 philosophers [desire to learn] that which is simply beautiful. In order to show this, he establishes first what the difference is between the simply beautiful and the many beautifuls. And he shows that the former is one, but the latter are this very thing in multiple instances (476a). And again, he shows from opposites that beauty itself (to autokalon) is one. This is because if the opposites are two, beautiful and ugly, each of these is one, since two is the coming together of two ones.