The relationship between philosophy and law is one of the classic questions for historians of Western political thought. Since texts and thinkers from ancient Greece and Rome are generally considered foundational for this tradition, they have received ample attention in the ever-expanding bibliography. On the one hand, many insightful studies have traced the influence and reception of ancient philosophy and/or Roman law on later periods. On the other, there have been numerous attempts, especially in German and Italian scholarship, to pin down the interactions between philosophy and law in the ancient world itself—often with an agenda to explain how the Late Roman Republic / Early Principate became such a key moment for Western thinking. In comparison to the reception perspective, however, the ancient question has proved to be much more intractable. No real consensus exists for the major problems, whether they concern Roman conceptions of justice or the nature and evolution of notions such as natural law, rights, and property. Where agreement does seem to exist, it is limited to a few general and self-evident points, such as that Roman jurists had “come into contact” with “dialectic,” as it is sometimes put. Now, the extremely fragmentary state of the sources, especially for the Republic, is undoubtedly a major cause of this situation. But once we turn to the evidence that has survived, we are faced with two additional problems of a fundamental nature. The first kind of problem is conceptual-historical. What is law and legal discourse, and what was it? What is or was philosophy and philosophical discourse? And in what ways did such discourses interact? The second kind of problem is source-critical: since studies of the lead-up to Late Republican and Early Imperial thinking rely so much on Cicero, his status as a writer of intellectual history matters. Are we looking at Hellenistic/Republican history? Or are we looking at what is essentially a Ciceronian construction of that history, especially the history of jurisprudence?
Brouwer’s monograph takes up what I have called the ancient question and provides a number of admirable new insights. The book takes the following positions: (a) influence flows in both directions: from philosophy to law and from law to philosophy; (b) the philosophy is primarily Stoicism; (c) knowledge exchange takes place primarily through personal interactions between specialists (for example, in intellectual “circles”) rather than through the circulation of texts or through education, whether geared towards specialists or wider audiences; (d) the relevant intellectual exchange took place overwhelmingly in the window 150–50 BCE; (e) Cicero is by far the most important source for both law and philosophy in this period; (f) Cicero’s presentations of intellectual history are largely accurate and need very little further discussion.
After a succinct and somewhat quirky sketch of the wider history of Greek and Roman interactions (Chapter 2), Brouwer presents several detailed case studies that analyze conceptual correspondence and are capped by thoughts on how the ideas in question might have spread. Brouwer is careful: he is not promising an encyclopedic treatment, nor does he claim to be offering the final word (for example, he promises to return to the topic of natural law in later work). Rather, he has selected a few areas for analysis, teasing out details and trying to offer new insights and new ways of thinking. Chapter 3 is about the systematization of law – sometimes sanctified in the scholarship as the birth of Roman legal “science.” The chapter argues that jurists’ definitions by means of genera and species are a clear indication of their knowledge of Stoic philosophy. The evidence here is a speech of Crassus in Cicero’s De oratore and Pomponius’ use of the term generatim in relation to Quintus Mucius Scaevola the Pontifex. Chapter 4 discusses the emergence of the regula in law, designating not so much a legal rule as a condensation of a legal case decision. The occurrence of the term (usually Greek κανών) in grammar and philosophy is highlighted, including Chrysippus’ famous definition of law, νόμος, as κανόνα … δικαίων καὶ ἀδίκων. Despite acknowledging that the earliest attestation of regula in Roman law is in an (indirect) fragment of Masurius Sabinus (fl. under Tiberius), Brouwer argues that the philosopher Panaetius could have rearticulated the Chrysippean notion and inspired jurists of the 120s BCE. Chapter 5 takes on “person” as a conceptual category. Brouwer points out in detail that Panaetius’ On Appropriate Actions developed a way of thinking about ethics for less-than-perfect individuals—that is, ethics for people other than the Stoic Sage. Central to Panaetius’ discussion is the idea of “roles” open to, or to be played by, individuals. According to Cicero’s De officiis, this idea may have provided Roman jurisprudence with the notion of the person. Chapter 6 makes the case for the influence of Roman law’s casuistic method on philosophy. The Stoics’ shift in focus from Sage to less-than-perfect person also meant a shift of perspective from virtuous actions to appropriate actions. Brouwer argues that this shift, paired with an exposure to Roman juristic reasoning, encouraged Stoic philosophers to discuss difficult cases using brief scenarios. The evidence here is Cicero’s rendering of Hecato’s discussion of a series of cases that reference the views of Diogenes of Babylon and Antipater of Tarsus. Chapter 7 traces a change in the way Stoics talk about justice, suggesting that they conceptualized it increasingly in terms of property distribution. Taking his cue from Cicero, Brouwer argues that this points to the influence of Roman legal thinking on philosophers such as Panaetius.
It will be obvious that an assessment of the book’s argumentation is closely tied up with one’s position on the key problems discussed above—which remains for a considerable part in the realm of assumptions. Mindful of this, I will offer several observations where evidence does play a role, and where Brouwer’s choices have affected the picture of the intellectual culture and flow of ideas that his book sketches.
First the case studies. Some of these clearly work better than others. The main point of Chapter 3 relies almost entirely on a passage in Cicero’s De oratore, which Jill Harries among others has argued is rather tendentious and manipulative. Yet there is no real discussion of this problem. Next, while Brouwer does a meticulous job establishing conceptual correspondence, especially in Chapters 4–6, the historical dimension of the discussions may raise more questions than they solve (see below).
There are also questions about the selection of cases. Most chapters focus on fairly abstract structures of thought and argumentation (Chapters 3–6) rather than on substantive legal doctrine and the values underpinning doctrine (but see Chapter 7). Now, precisely because the source record is generally so problematic, it is really too bad that Brouwer does not include a discussion of natural law, even though he does offer an important consideration in passing: the Stoic shift to appropriate actions may have encouraged the development of “a set of general precepts that can reasonably be applied in most cases” (p. 61). Similarly, Brouwer’s thoughts on the topic of rights would have been really welcome.
I have graver concerns about the historical dimension to Brouwer’s project. The sketch of the history (including the intellectual history) of the Hellenistic/Mid-Republican period – found primarily in the preliminary chapter – is partial and contestable. This matters because it deeply informs the discussions of the circulation of ideas in the book’s core chapters.
To begin with a seemingly pedantic point, the work’s general sense of chronology limits rather strongly how we might think about intellectual cross-fertilization. Brouwer puts most of his money on the so-called Scipionic circle, which counted Stoic philosophers as well as jurists among its members. Most of the book weaves a narrative around Panaetius as the great influencer, based (by necessity) on the evidence of Cicero and an admixture of further assumptions. It was only this generation that was able to pull off the intellectual exchange, we hear, because Roman contact with Greece was not fully established until Rome’s dealings at Pydna in 168 BCE, and philosophy was not properly introduced to the Romans until the famous embassy of the philosophers in 155 BCE. But is this picture plausible? Or is it at least more plausible than alternatives? Pydna seems to be a fairly arbitrary and late point on which to pin contact with Greece. Whatever one thinks about “Hellenization” in the Western Mediterranean (Etruria, Latium, Carthage, etc.) in the Archaic and Classical periods, clearly Rome had intense interactions with Magna Graecia not later than the third century BCE. Tradition has it that the Romans embraced and imported Greek literature from there at the end of the First Punic War. In addition to establishing a base at Dyrrachium in 229, the later third century saw the Romans interact with the Ptolemies, Pergamon, and Rhodes—all known for their intellectual culture. The philosopher-grammarian Crates of Mallos may have spent time in Rome in 167. The Senate passed a resolution banning philosophi and rhetores from the city of Rome in 161: they had apparently been teaching there in considerable numbers and for some time. If this calls for the embassy story to be handled critically, its stereotyped narrative form, as a Roman-style origin story, makes the call for caution even stronger. All of this goes to show how much depends on one’s view of bigger-picture chronology. For Brouwer, it was not until Panaetius’ generation that major interactions between philosophy and law were possible; yet one could accept that interaction started earlier and took place over a longer time without denying that Panaetius and friends played some role.
This brings me to another point, namely the transmission channels through which philosophy and law may have influenced one another. Brouwer’s emphasis on the interactions between philosophers and jurists in the generation after 155 BCE makes rather heavy-handed assumptions about the ways ideas spread. Is it plausible that notions such as genera and species as well as regulae can only have come from the mouth (or pen) of a technical philosopher? I think that here Brouwer’s decision to leave aside the rhetorical tradition raises big questions. There is good evidence that the Roman elite were trained rhetorically by the late third century. The Late Republican rhetorical handbooks, which are a based on a tradition of now-lost Greek rhetorical handbooks, clearly incorporate logic-based tools. It is therefore possible that some of the Hellenistic treatises contained instructions about, among other things, definition by genera and species. As a separate point, rhetoric may also have had considerable importance for the development of casuistic thinking: rhetorical training appears to have involved giving mock speeches on the basis of scenarios since the early Hellenistic period, and rhetorical practice in courts and other public arenas must often have been prompted by specific cases or situations. This must have encouraged students to strip cases to their core, analyze specific problems, and compose detailed arguments—whether these students went on to become orators, philosophers, jurists, or people who combined the activities characteristic of those professions. The rhetorical tradition should, on this view, be seen not simply as a repertoire of persuasive tricks but as a repository of enormously influential ways of thinking.
All of this is not to say that Brouwer must be wrong: I have meant to show how much room for debate there is. Brouwer’s book is brimming with stimulating material and is a valuable contribution to that difficult debate.
 J. Harries, Cicero and the Jurists, London 2006, pp. 108-115.
 For the last two points, see Suetonius, De grammaticis et rhetoribus 2.1, 25.2, with Kaster’s commentary.
 Collection of evidence at J. Connolly, ‘The New World Order: Greek Rhetoric in Rome’, in: I. Worthington (ed.), A Companion to Greek Rhetoric, Chichester 2010, pp. 141-6.