BMCR 2014.01.17

Aristotelianism in the First Century BCE: Xenarchus of Seleucia

, Aristotelianism in the First Century BCE: Xenarchus of Seleucia. Cambridge; New York: Cambridge University Press, 2012. xi, 227. ISBN 9780521876506. $95.00.


Xenarchus of Seleucia was a contemporary of Strabo who was active as a teacher of philosophy in Alexandria, Athens and Rome at the time of Augustus. Falcon’s study is the first monograph to be wholly dedicated to this Peripatetic writer, from whom a few fragments survive, almost exclusively in commentaries on Aristotle by Alexander of Aphrodisias and Simplicius.1 Falcon offers a close reading of all the relevant source material, with a view to offering ‘as complete a picture of Xenarchus as our sources permit’ (Introduction, p. 1). The first part of the study discusses the historical and philosophical significance of Xenarchus’ views on physics and ethics, while the second part contains all the evidence concerning Xenarchus’ life and work (fragments and testimonia), arranged thematically (physics, psychology, ethics, and work ‘on the Timaeus ’), accompanied by an English translation and a set of explanatory notes. The last part of the book comprises three short essays on the reception of Xenarchus in late antiquity and the Middle Ages, and a conclusion.

The fragments of Xenarchus point to a secure familiarity with the Aristotelian texts, and thus Falcon plausibly concludes that the philosopher was active after the re-kindling of interest in the ‘esoteric’ works of Aristotle at some point in the first century BC (Introduction, p. 1); the thorny issue of the channels of availability of Aristotelian texts in this period, and the influence of Andronicus’ edition in this process, does not, however, receive much attention (owing without doubt to the scarce evidence available).

Falcon positions Xenarchus in the early Peripatetic exegetical movement but dissociates him (despite the title of the book, which might suggest otherwise) from ‘concern for orthodoxy’ and systematization as represented, most conspicuously, by Alexander of Aphrodisias (e.g. p. 21). Xenarchus appears thus as reflecting a phase whereby philosophical engagement with the text of an authority was compatible with a critical attitude towards the views expressed in the text and with a certain freedom to offer alternative views; in this respect Xenarchus follows the tradition of the Hellenistic Peripatos, and the example of people like Strato who, although members of the Peripatetic school, departed significantly from Aristotle, e.g. on the nature of the soul. Falcon stresses thereby that Xenarchus operated with a ‘thin’ concept of authority (p. 8), which allowed creative readings while still claiming the title of Peripatetic for oneself; there is a clear departure here from the picture of Xenarchus as an ‘anomaly’ within the Peripatetic tradition which is suggested in Moraux’s seminal work Der Aristotelismus bei den Griechen.2

Xenarchus is most famous for the attack that he launched against the doctrine of the existence of a special, indestructible fifth element which accounts for the cyclical motion of the celestial bodies. This was presented as a standard Aristotelian tenet in D.L. 5.32. The evidence for his criticism comes from Simplicius’ commentary on the Aristotelian De Caelo : besides aporiai (T2), Xenarchus offers an alternative explanation, which makes the lightest of the four material bodies, namely fire, into the constituent of the heavens; when fire reaches its natural place (and thereby its perfection), Xenarchus argued, it naturally performs a circular motion which explains the movement of the celestial bodies without the need to invoke a special, immaterial body (T3). In another fragment, Xenarchus attacked the Aristotelian ‘principle of the uniqueness of natural motion’ (pp. 88-9), according to which one and only one natural motion corresponds to each of the simple bodies (T5). Falcon advances the thesis that Xenarchus’ critique was part of a collection of ‘difficulties’ on the Aristotelian text (p. 25) rather than of a philosophical commentary. T12 reveals, in addition, an engagement with Stoic ideas, and attests the defense of the Stoic position of existence of extra-cosmic void.3 As Falcon notes, this should not mislead us into reading a Stoic influence into his criticism of the fifth substance as well (p. 116), since the arguments for the critique there seem to derive from within the Peripatetic conceptual apparatus itself.

The inclusion in the ethical debate of the foundational question of what is ‘the first thing that is appropriate to us’ is attested already in a divisio of the Academic sceptic Carneades ( Fin. 5.17) and a response to this topic was developed in the aftermath of Carneades by all philosophical schools (perhaps it is too hasty on Falcon’s part to call it an exclusively Stoic framework: p. 47). Alexander in his Mantissa sketched the views of some late Peripatetics who formulated their position on the prôton oikeion on the basis of Aristotle’s text (the locution τῶν παρὰ Ἀριστοτέλους in the title means ‘from the teachings of Aristotle’). Xenarchus developed as a response to this methodological demand an egoistic position according to which what moves us from birth onwards is the love of oneself tout court. The lack of specification of this position prompted Alexander to reject it as ‘not elaborate’ enough. Perhaps it would have been instructive to compare Xenarchus’ position here with that of Antiochus who, before Xenarchus, had developed a Peripatetic position which also made use of the concept of self-love in the context of the foundational discussion of the ‘first object of desire’ ( Fin. 5.27-8). Still, Xenarchus seems to be innovative in using explicit Aristotelian textual evidence to support his thesis. Although the fragment on the prôton oikeion clearly suggests an engagement with the Aristotelian text, it also shows an ad hoc attempt to find evidence for a thesis that is nowhere clearly articulated in Aristotle; it is surprising that Xenarchus does not cite in this context Politics 2, 1263b1, which would have been a much better testimony to the idea that Aristotle defended a natural love of the self (μὴ γὰρ οὐ μάτην τὴν πρὸς αὑτὸν αὐτὸς ἔχει φιλίαν ἕκαστος, ἀλλ’ ἔστι τοῦτο φυσικόν). This omission might be again connected with the circulation of the Nicomachean Ethics and its status as the canonical expression of Aristotelian ethics in the period of Xenarchus’ activity.

Falcon’s style is characterized by clarity, and the translation of the fragments and testimonia is accurate and helps the reader to follow the precise steps of Xenarchus’ argumentation. Typographical errors are absent with few exceptions. I note the following: p. 36 ‘simply body’, p. 62 ‘presumabily’, p. 90 ‘into into’, p. 124 ‘intellegible’, p. 136 ‘coumpound’, p. 138 ‘hylomporphic’, p. 142 ‘To to’, p. 150 ‘make use the word’, p. 204 n. 13 ‘within in’. The editor in some cases opted for transliteration of the Greek without indication of the quantity of vowels in the original writing: Thus, αἰθήρ becomes aither (p. 1) and not aithêr, ἐξηγηταὶ, exegetai (p. 23, 167) and not exêgêtai, διαφωνία diaphonia (p. 130 n. 183) and not diaphônia; but ζητήματα is printed as zêtêmata, ἐκπύρωσις as ekpyrôsis and πρῶτον οἰκείον as prôton oikeion. It would be best if a uniform way of transliterating the Greek were adopted throughout the book.

All in all, Falcon’s book constitutes a valuable tool for the study of a period of philosophical activity that is still surrounded by mystery, and contributes to the better understanding of the hermeneutical strategies towards Aristotle’s text that preceded the development of the commentary tradition in the Imperial period.


1. Fragments of Xenarchus may also be found in Robert Sharples’ 2010 anthology, Peripatetic Philosophy 200 BC to AD 200: An Introduction and Collection of Sources in Translation, Cambridge.

2. P. Moraux, Der Aristotelismus bei den Griechen, vol. 1, Berlin 1973.

3. The association with the Stoic Arius of Alexandria (T1) might have played a role for this attested active interest of Xenarchus in Stoic ideas.