The importance of this collection of essays is that it is the first to be entirely devoted to the long philosophical inscription of Diogenes of Oinoanda. Originally presented at a conference in Turkey (2014), the essays are arranged by the editors roughly according to the chronology of the philosophers and schools of thought with whom Diogenes polemicises explicitly or implicitly. The essays examine the fragments of the inscription, both those known previously as well as those newly discovered (2007–2012), the historical background to Diogenes’ arguments, the sources from which he draws, and his philosophical and literary originality.
The volume opens with a foreword by the noted scholar M.F. Smith on ‘The Importance of Diogenes of Oinoanda’, followed by the editors’ general preface (H. and M.). The twelve essays begin with two discussions by two members of the Oinoanda surveys (2007–2012): the late M. Bachmann and H., who introduce the ongoing complex reconstruction of Diogenes’ inscription in the context of other Oinoanda remains. The ten core essays naturally differ in views on a variety of issues, some of which should be noted.
The newly discovered (2008) NF 155 (classified as Maxim) criticises Plato's cosmology and is discussed in two essays: M. Erler examines the traditional Platonic debate about the interpretation of Plato's Timaeus and the demiurge's role in the world, observing how Diogenes uses an Aristotelian argument against the asymmetry of the thesis of creation by a demiurge without necessitating destruction of the world. He traces back to Aristotle Diogenes’ metaphorical use of the rare phrase of physis as a demiurge, where the description of nature as a creator does not imply providence (e.g. PA 1.5.645a9). Diogenes thus ‘hints at an Aristotelian answer’ to a middle-Platonist literal interpretation that answered the Epicurean critique of providence, explaining the asymmetrical thesis by the demiurge's continuing providence (likewise maintained by Diogenes’ near contemporary Atticus, Eus. Praep. Ev. 15.6.13). Erler also analyses an anti-Platonist allusion in fragment NF 167.III + NF 126.I.7–II.5, concerning the wise man and law.
F. Verde examines the use Diogenes makes of the past in NF 155 and fr. 5 in respect to the sceptic view that nothing is knowable due to the rapid flux of things attributed to Aristotle. In contrast to Erler, Verde argues that Diogenes’ ‘physis demiurge’ is a critical allusion to the Stoics, whose doctrine was considered close to the Platonists’ and who derived their concept of god from Plato's demiurge. He convincingly compares it with Velleius’ speech (Cic. ND 1.18–24) criticising Plato's demiurge and Stoic providence together, argued in an anti-Stoic context, but otherwise comparable to NF 155, that ‘the world was made by nature’ (I.53). Verde concludes that Diogenes’ source is possibly late Epicurean (as was Cicero's), employing already existing anti-Platonic arguments against the Stoics. While Erler's and Verde's conclusions differ, they both mention R. Chiaradonna's recent work on this subject (2015), which offers another interpretation.
Verde's argument presupposes Smith's suggestion that NF 155 and fr. 100, which mentions the Stoics and ‘matter’ (I.3–4), originally stood close to one another and were related contextually. However, this is merely speculative, as he acknowledges, since it relies on Smith's conjectural supplement to fr. 100 (2003, Suppl. edition, p. 118) and its comparison with Velleius’ speech (Cic. ND 1.19).
Next, G. Leone surveys Diogenes’ polemic concerning celestial phenomena, indicating the ethical contexts of numerous references. Leone argues that this polemic is mentioned in fr. 4 as part of a general anti-sceptic argument regarding the usefulness of the study of nature. In frr. 13 and 14 this argument provides Diogenes with the context he needs to present Epicurus’ theory of multiple explanations, though he does not deviate from Epicurus despite claiming that a single explanation may be regarded as more plausible. The mention of celestial phenomena in fr. 20 + NF 182 (discovered in 2010) in reference to the ethical context of the ‘Theological Physics-Sequence’ is brought against Stoic beliefs concerning the role of god in the universe. Leone argues that Diogenes’ lexical and logical formulations follow Epicurus conceptually, but his way of applying them against anti-Epicurean Stoic arguments is innovative.
The three following essays concern the debate about the interpretation and restoration of fr. 33: namely, does Diogenes target the Stoics, as Smith suggests, or the Cyrenaics, as D. Sedley suggests? While J.-B. Gourinat follows Smith (pp. 179–83), V. Tsouna follows Sedley (pp. 148–54). Most outstanding is F. Masi's novel interpretation of the argument developed in fr. 32, NF 192, fr. 33 and NF 128, proposing that Diogenes targets both Stoics and Cyrenaics. Diogenes accuses the Stoics of misinterpreting the Epicurean goal, pleasure, and its relation to virtue, reducing it to a Cyrenaic interpretation. Diogenes therefore distinguishes between Epicurean and certain Cyrenaic views. Theodorus of Cyrene's circle, for example, seems to turn virtue into the goal and pleasure into an intermediate state. The Cyrenaics associated with Anniceris ‘acknowledge the instrumental function of virtue with respect to pleasure’ (p. 136), but wrongly understand virtue as an antecedent cause of pleasure. Masi convincingly interprets the vocative ὦ ἄνδρες in fr. 32.I.6 as an address not to the readers of the inscription but to the Stoics, and the following pronoun τούτων (32.I.7) as an indirect address to the Cyrenaics.
Tsouna brings fresh observations in support of Smith's suggestion that fr. 49, targeting Aristippus, and fr. 44 come closely. She gives an anti-Cyrenaic motivation to fr. 44 concerning laymen who are incapable of calculating which is greater, bodily pleasures and pains or mental ones. She leaves their exact order unclear. Tsouna supports Sedley's interpretation and restoration of fr. 33, but innovatively associates some fragments with the Cyrenaics (frr. 2–3, 4, 29, 34, NF 146, 157, 184). For example, she plausibly suggests that NF 146 (discovered in 2008) can be ‘read as an implicit rejection of Cyrenaic pleasures’ since the examples mentioned there are of things that do not create discomfort but rather satisfy natural desires; this reading implies that pleasure is absence of pain rather than excessive enjoyment. Tsouna also speculates that Diogenes polemicises against the Cyrenaic school despite the fact that it had disappeared because he finds it ‘philosophically challenging’ and follows Epicurus who had previously targeted it. Masi also argues that Diogenes is opposed to the reduction of Epicurean views to Cyrenaic interpretations.
The next three essays contribute to understanding Diogenes’ polemic on dreams. Gourinat reviews Diogenes’ frequently made arguments against the Stoics in the so-called physical and ethical treatises, and points out that many are original counter-attacks to the Stoics’ anti-Epicurean arguments. Gourinat argues that in fr. 10 Diogenes employs an epistemological strategy against sceptics and anti-Epicurean arguments by juxtaposing the correct view of the Epicureans in between two extreme views, that of the Stoics’ and that of Democritus’. Employing the Epicurean term ‘void’ (10.I.4–10; II.9–10) he claims that the Stoics deprive the images of dreams of their power, since they have no real (i.e. are empty of) external physical causes. By contrast, Democritus gives dreams prophetic power that they do not have (fr. 10.IV.10–V.6). Gourinat attempts to unravel Diogenes’ misrepresentation of the Stoics.
G.’s analysis largely agrees with Gourinat's, but adds observations on Diogenes’ original rhetorical presentation. G. examines sceptic criticism (e.g. Plutarch, AC 28–29.1123B–1124B) and Epicurean anti-sceptic arguments that demonstrate how the Epicurean claim that all perception is real (based on Democritus’ atomism) ultimately exposed the Epicurean theory of perception to a sceptical attack; Democritus’ opinion is that dreams have prophetic power and Epicureans considered dreams to be really true. The contrast between Democritus and the Stoics allows Diogenes to present the correct Epicurean view by distinguishing ‘the factive perceptual core of the visual experience [of dreams] from its doxastic component’ (p. 199); i.e., the false opinions of the dreamer on what he perceives (simulacra) as his senses are inactive while sleeping.
A. Gigandet examines Diogenes’ argument on perception, imagination and dreams presented in fr. 9, in light of Lucretius’ passages on dreams. He unravels the perception process that begins with external objects, ‘first images’ (εἴδωλα) entering the eye channels and ‘facilitating’ the path into the soul for more flow of images similar to them in size and shape. Gigandet discusses what Diogenes means when he says that the nature of the soul becomes porous, discerning images that penetrate the soul directly rather than through the eyes, in the absence of external objects. Gigandet emphasises that the highly iterative nature of the process is needed in order to recall thoughts, imagination, dreams, physical selection of what the subject perceives, and the ethical responsibility for his interpretations that therefore lies within each person.
M. discusses Diogenes’ ambivalence towards politics as it manifests itself in his polemical arguments (e.g. frr. 3, 29.I–II + NF 207, 30, 112, 51, 56) against political engagement (consistent with Epicurean tradition) but demonstrating social concern. Most notable are M.’s points concerning Diogenes’ rejection of the Stoics’ view of the role of god in the context of law, justice and the city (Theol. Phys. Sequence), that their ignorance of physics leads to ignorance of political realities; Diogenes’ description of the Golden Age (fr. 56) may have competed with other conceptions of the Golden Age; M. introduces a possible interpretation of Diogenes’ proclamation about a time when society will no longer need laws because it will be guided by wisdom hypothetically attained in the future, contrary to the general scholarly view that interprets this proclamation as a prediction. Furthermore, M. argues that Diogenes’ cosmopolitan description in fr. 30 uses terminology of Epicurean cosmology and does not exclude divisions to cities but is indicative of Diogenes’ imperial time. M. speculates about Diogenes’ sources (e.g. Hermarchus; Cicero, De Finibus), concluding that in these fragments his originality probably manifests itself mostly in a rearrangement of traditional doctrinal elements in his own style and social context.
It seems fitting that this collection concludes with G. Roskam's attempt at the first systematic analysis of Diogenes’ rich polemic approach, which he puts to test on the ‘Theological Physics Sequence’. Roskam convincingly indicates that Diogenes’ motivation to cure people of false opinions with his inscription (fr. 3) requires a polemical approach against these opinions. He claims that Diogenes uses traditional polemical techniques, but always takes into account his epigraphic medium and his target readers. This includes: refraining from engaging in inner school polemics, conciseness, relative politeness, a systematic approach as a schoolmaster and rhetoric. That Diogenes’ arguments were designed for an epigraphic medium is arguable, as Roskam mentions briefly at the end of his essay, though he hastily dismisses it. Parts of Diogenes’ inscription may have been based on works that he circulated before conceiving the inscription.
Since the recovery of the inscription is still ongoing, the essays present the cutting edge of research. It is a welcome contribution to the study of Diogenes’ philosophical critique in its historical context and to understanding the extent of his originality. It will no doubt generate scholarly comment and interest.
