Roman Stoicism has been enjoying something of a renaissance in recent decades, with a number of works dedicated to recuperating the philosophical importance of Seneca, Epictetus, Marcus Aurelius, and even Lucius Annaeus Cornutus. John Sellars’ Marcus Aurelius, the second volume to appear in Routledge’s “Philosophy in the Roman World” series, continues this trend by aiming to demonstrate that Marcus was a “committed Stoic philosopher” and not the “confused eclectic thinker” that some commentators have taken him to be (2). The view that Marcus was uninterested in logic and physics, and that the Meditations is merely a work of practical ethical advice, rests in his estimation on a false dichotomy; the project of self-cultivation that Marcus undertakes through his writing of the Meditations “presupposes Stoic logic and physics as much as it does ethics” and “is built upon foundations found in all three traditional parts of Stoic philosophy” (2). To see how this is the case, Sellars argues, we must appreciate the literary form of the Meditations as a series of exercises designed to facilitate the assimilation and digestion of key philosophical principles. These exercises (and the Meditations itself) do not displace the necessity of grasping such principles at a theoretical level; rather, they constitute the second stage of a Stoic conception of philosophy as an art of living, one whose first stage centers on understanding philosophical principles on a theoretical level. Appreciating Marcus’ engagement with Stoic philosophical principles, then, requires unpacking these exercises and the Stoic doctrines that they presuppose. It is Sellars’ task in this book to do just that and, in doing so, to show that Marcus was as much of a Stoic philosopher as anyone could be within his time and place (15).
The book is divided into nine chapters (distributed over four parts), with a preface, introduction, conclusion, and appendix that offers a brief history of the text and editions of the Meditations. In what follows, I offer a brief summary of the book’s main arguments, followed by some critical reflections.
The first chapter (“Marcus the Stoic Philosopher”) considers the historical evidence for Marcus’ engagement with Stoic philosophy. Here, Sellars makes good use of Marcus’ correspondence with Fronto to demonstrate that the former’s engagement with Stoic thinkers and ideas was broader and deeper than a reading of the Meditations alone might suggest. For example, though Marcus never mentions Seneca in the Meditations, Fronto’s chiding reference to “your Annaeus” indicates at least that Marcus was reading Seneca (12). Fronto also notes Marcus’ interest in logical problems like the Liar paradox, an interest which appears entirely absent from the Meditations (39). How important such interests remained for Marcus later in his life when he wrote the Meditations is unclear; nevertheless, we learn that his knowledge of Stoicism was neither confined to nor derived primarily from Epictetus’ Discourses.
The second chapter (“The Meditations, a philosophical text”) turns to the literary form of the Meditations, arguing that the text itself constitutes a series of practical exercises aimed at digesting core Stoic principles. Here, Sellars defends Pierre Hadot’s use of the term “spiritual exercises” by amassing the evidence for such forms of askêsis within the Stoic tradition. Sellars argues that these practices fit within a specifically Stoic conception of philosophy as an art of living, one that is best understood via analogy with other technai, such as medicine. In technai, theoretical principles must be studied and grasped, and also applied to practical situations – “one must also engage in a period of training in order to digest those principles so that one is ready to put them into practice” (26). This metaphor of digestion, as Sellars shows, is used by both Seneca and Epictetus. While Marcus prefers the image of dyeing something to the core (which requires repeated exposure to the dye), the purpose of both images, digesting and dyeing, is nonetheless the same, which is to emphasize that “practical exercises come after the study of philosophical theories, upon which they are grounded”; they “do not challenge or replace the sort of rational inquiry usually identified with philosophy; they supplement it” (33). To argue, then, that the Meditations itself is a spiritual exercise in this sense requires appreciating the role it is meant to serve in assimilating the philosophical principles Marcus had already encountered.
Chapter 3 (“Impressions and judgments”) considers Marcus’ treatment of logical topics in the Meditations. Here, Sellars addresses the concern that Marcus’ imprecise use of logical terms betrays a poor understanding of the theoretical foundations of Stoic philosophy. In his use of the language of impressions, Sellars notes (following Hadot) that Marcus does indeed seem to blur some conceptual boundaries. For example, a passage like “wipe out impressions” (8.29) might lead us to conclude that Marcus simply misunderstood the Stoic conception of phantasia; yet Sellars contends that what Marcus “really means is wipe out impressions that have become infected with judgments,” rather than all impressions (since the latter would be both a logical and psychological impossibility) (43). This interpretive charity is warranted by the fact that, elsewhere, Marcus’ apparent departures from the use of logical terminology by earlier Stoics is not necessarily indicative of any misunderstanding on his part. Thus, that Marcus tends to take a more cautious approach to impressions than the earlier Stoics (who maintained that they are generally reliable) is a divergence that is best explained by a difference in focus; while the earlier Stoics were mostly concerned with rebutting the epistemological challenges put forth by the Academic Skeptics, Marcus is focused on impressions that have already been blended with value judgments and hence differ from our more reliable first impressions. This term “first impression” is also a unique expression (albeit one that echoes Epictetus, Diss. 3.8.5), yet again, we can understand it as an attempt to expand on earlier Stoic accounts of judgment in order to explain how it is that some impressions come to contain value judgments in the first place (42–44).
Chapters 4–7 are organized around Marcus’ treatment of a number of major themes within Stoic physics, and attempt to demonstrate that his concern with practical ethics was deeply informed by a grasp of the theoretical principles undergirding the Stoic conception of the physical world. Of particular importance is Sellars’ interpretation of the disjunction “providence versus atoms” that arises throughout the Meditations (73–77). Sellars denies that these reflections illustrate a skepticism concerning the providential ordering of the universe. Even where Marcus appears to suspend judgment regarding the alternatives, he continues to use Stoic language that affirms their view of nature. As with Seneca’s (and Marcus’) engagement with Epicurean ideas concerning death, it is best to approach this material as “common property” shared between the schools, rather than as betraying anything distinctly Epicurean about their thought.
Chapters 8 and 9 cover ethical and political topics that have received more sustained engagement within the secondary literature on the Meditations. Again, Marcus emerges from Sellars’ reading as an orthodox Stoic. Contra Hadot, Sellars finds no evidence of a systematic attempt to amend the core Stoic list of virtues (111); and, while Marcus’ emphasis on justice above the other virtues appears to be unique, this fits with his emphasis on our nature as rational and social beings (rather than betraying any Platonic influence) (111–13). Marcus’ cosmopolitanism, likewise, does not imply a radical rejection of his native citizenship but, as with Seneca, constitutes a recognition that there are two cities of which he is a citizen (119).
On the whole, Sellars succeeds in demonstrating that Marcus’ concern with practical ethics is not divorced from a serious engagement with logic and physics. By approaching the Meditations with interpretive charity, Sellars ably illustrates how Marcus’ apparent deviations from Stoic orthodoxy are often indicative of rhetorical emphasis, rather than disagreement or misunderstanding. His review of the evidence for “spiritual exercises” within the Stoic tradition reinforces and gives more nuance to Hadot’s pioneering work, and allows us to appreciate Marcus’ writing of the Meditations as a philosophic activity.
While I am largely sympathetic to the account provided by Sellars, there are places where a deeper engagement with the arguments critical of Marcus’ abilities as a philosopher may have been helpful. In particular, in responding to John Cooper’s challenge that Hadot misrepresents the prevalence and importance of what he terms “spiritual exercises,” Sellars does provide good evidence suggesting that these do indeed have ancient precedent (28–31); yet this would not seem to address Cooper’s deeper disagreement with Hadot, namely that what made ancient philosophies “ways of life” was not such spiritual exercises but a shared commitment to three core ideas: first, that reason is also a power of motivation for action; second, philosophy is directed toward perfecting reason; and, third, that knowledge is “psychologically decisive” when it comes to doing what is right and avoiding what is wrong. If Cooper is right, and if, as Sellars argues, such spiritual exercises come after the rational inquiry into the philosophical theories upon which they are grounded, then one might ask what purpose such spiritual exercises serve. Sellars argues that the “central task of such spiritual exercises … is to keep philosophical principles … ‘ready to hand’,” and that this will habituate us “to acting in accordance with those principles” (29). This is certainly correct, yet it might lead us to ask for further clarification regarding the relationship between the two stages of the philosophical art of living Sellars has identified. In particular, what level of theoretical understanding does one achieve during the first stage of this process, and precisely why is it unable to motivate us consistently to act in accordance with these principles? Do the spiritual exercises that constitute the second stage merely serve to habituate us to correct action, or do they also serve to complete our rational grasp of the theoretical principles we encountered during the first stage? In short, a more detailed account of where precisely these spiritual exercises fit within a Stoic account of moral psychology might help to more fully address the criticisms that Cooper has raised.
Second, it is worth noting that the charges that have been laid against Roman Stoics like Marcus are not just that of an incoherent philosophical eclecticism, but of a disappointing lack of originality. Thus, Long describes this period as one “when Stoicism had become an authorized doctrine rather than a developing philosophical system.” Though Long’s work on Epictetus should serve as an amendment to his earlier view, the point remains that part of the dismissal of Marcus as a philosopher is that he merely parrots doctrines developed by earlier Stoics rather than actively developing Stoic philosophy in new directions. In attempting to prove Marcus’ Stoic orthodoxy, Sellars does little to combat this view other than noting his unique use of the term “first impressions” and the emphasis he places on justice above the other virtues. That being said, the work Sellars has done in this volume to recover Marcus’ understanding of Stoic logic and physics could provide a firmer basis for a more secure examination of his philosophical originality and will serve as a useful caution for future scholars against viewing any deviation from Stoic orthodoxy as necessarily a sign of Marcus’ philosophical ineptitude.
 See, for example, A.A. Long, Epictetus: A Stoic and Socratic Guide to Life, Oxford 2004; B. Inwood, Reading Seneca, Oxford 2005; M. van Ackeren, Die Philosophie Marc Aurels, Berlin 2011; and G. Boys-Stones, L. Annaeus Cornutus: Greek Theology, Fragments and Testimonia, Atlanta 2019.
 J. Cooper, Pursuits of Wisdom, Princeton 2012: 11-14.
 A.A. Long, Hellenistic Philosophy, Berkeley, CA: 115.
 Cited above in n. 1.