I.1 The “Cosmological Doctors”

On the broadest possible application of the term, we all engage in “cosmology” whenever we step back from the world of everyday experience to talk about what is real, permanent, and universal. When Pericles tells the Athenian assembly that their power may one day diminish, “for all things naturally depreciate” (πάντα γὰρ πέφυκε καὶ ἐλασσοῦσθαι, Th. 2.64.3), or when the Athenians inform the Melians that they will not relent, for the stronger rule the weaker “on all occasions by a natural necessity” (διὰ παντὸς ὑπὸ φύσεως ἀναγκαίας, Th. 5.105.2), these speakers offer “cosmological” explanations in the sense that they account for specific actions or events by appealing to the operation of universal laws. In these two examples, the fall of the Athenian empire and the invasion of Melos are historically defined events, confined to a specific point in time, but they are governed by principles that hold true διὰ παντός (at all times and in all places). The principles underlying these events are “cosmological” in the sense that they present the world as a cosmos, a natural order that is both consistent and universal. The cosmologist observes the orderly progression of nature – the rising and setting of the sun, the waxing and waning of the moon, the changes in the seasons, the rotation of the heavens – and extrapolates from these a more general assumption that all things form part of a natural order, which governs both the world around us and, by implication, our own interactions with that world.

The following study concerns a group of physicians I will call, for lack of a better term, “cosmological doctors.” These doctors all lived in the Greek-speaking world during the fifth and fourth centuries bce. What defines them as “cosmologists” is their attempt to base the art of healing on the first principles of all things in general. The precise nature of their first principles varied greatly depending on the author. Some of these doctors focused on the material elements from which all things are composed. Others emphasized the fundamental “powers” (δυνάμεις) that govern all things. Many isolated the general patterns that can be found in all corners of the universe, drawing analogies between the macrocosm of the universe and the microcosm of the human body. What unites these thinkers is not the identity of their first principles but their emphasis on the universality of such principles. These doctors isolated principles that govern all things in general, and they applied those principles to the everyday practice of treating and preventing disease.Footnote ¹

For most students of Greek literature, the best-known example of a “cosmological doctor” is the physician Eryximachus. His speech in Plato’s Symposium defines eros (“love”) as a universal power, present “in the bodies of all animals, in the things that grow in the earth, and in practically all that is” (ὡς ἔπος εἰπεῖν ἐν πᾶσι τοῖς οὖσι, 186a). In support of this thesis, Eryximachus constructs what amounts to an argument by induction. He compares the role of eros in six crafts (medicine, gymnastics, agriculture, music, astronomy, and divination) in order to show that this principle “extends over everything, both human and divine” (186b) and “has a great, a strong, nay an absolute power” (188d). The Hippocratic treatise On Breaths describes pneuma (“breath, wind”) in similar terms. Pneuma is “the greatest potentate in the universe and over the universe” (μέγιστος ἐν τοῖσι πᾶσι τῶν πάντων δυνάστης, 3.2, 6.94 L.), and it is also the “starting point and source” (ἀρχὴ καὶ πηγή, 1.4, 6.92 L.) of all diseases in the sick. On Regimen asserts that all animals, including humans, are composed of fire and water. Fire has the “power” (δύναμις) to move all things, water the power to nourish all things, and these two substances are “sufficient in themselves, both for each other and for everything else” (αὐτάρκεά ἐστι τοῖσί τε ἄλλοισι πᾶσι καὶ ἀλλήλοισιν, 3.1, 6.472 L.). Another text, On Flesh, presents anatomy in a framework of anthropogony. It begins by dividing the cosmos into the hot, the cold, and the wet, and it then explains how each part of the body, with the aid of the “fatty” (τὸ λιπαρόν) and the “glutinous” (τὸ κολλῶδες), arose from these three substances. Then there is the Anonymus Londiniensis, a first-century papyrus that summarizes earlier medical theories, which mentions several Greek doctors with an interest in cosmology. To cite just one example, Philistion of Locri is said to have held that humans are composed of four “forms” (ἰδέαι): fire, air, water, and earth. To each of these forms he assigned a “power” (δύναμις). To fire he assigned the hot, to air the cold, to water the wet, and to earth the dry (XX.25–37).Footnote ²

This list could be expanded with other known cosmological doctors: figures such as Petron of Aegina, the unnamed opponents of On Ancient Medicine, and Polybus of Cos (the presumptive author of the treatise On the Nature of the Human Being). Together, they suggest that the Classical period was a time when many Greek doctors were interested in cosmology. It was a time when medical writers were attempting to base the art of healing on a limited number of principles, generalized to the highest possible degree, while asserting that the same “powers” (δυνάμεις) that govern the universe in its entirety are also the “starting point” (ἀρχή) of all changes in the body. As the author of On Ancient Medicine succinctly notes, many doctors in this period were attempting to speak or write about medicine “after laying down a foundation for their account” (ὑπόθεσιν αὐτοὶ ἑωυτοῖσιν ὑποθέμενοι τῷ λόγῳ, 1.1, 1.570 L.). They were “narrowing down the starting point of the cause [τὴν ἀρχὴν τῆς αἰτίης] of diseases and death for human beings,” and making that starting point “the same for all,” setting up “one or two” principles like “the hot, the cold, the wet, the dry – or whatever else they please” (1.1, 1.570 L.).

One of the goals of this study is to understand how these cosmological doctors came to be. What led them to adopt such universalizing theories, and what can their theories tell us about the priorities of Greek doctors in the fifth and fourth centuries bce? These questions are not easy to answer, primarily because the intermixture of medicine with cosmology cannot be attributed to any single, centralized authority. There was no “school” of cosmological medicine, no one thinker to whom all of these doctors were responding. Nowadays, most would agree that an important role was played by the “inquiry into nature” (περὶ φύσεως ἱστορία), the tradition of cosmological speculation that is commonly said to have begun with Thales, Anaximander, and Anaximenes of Miletus in the sixth century bce. It is now generally agreed that this tradition lent authority and inspiration to the cosmological doctors. The precise nature of its contribution, however, has never been clearly defined.Footnote ³

I.2 Medicine and Philosophy?

In previous treatments of the cosmological doctors, scholars have tended to begin with the framework of medicine’s interactions with “philosophy.” Under this rubric, the cosmological doctors are presented as either aspiring participants in the “inquiry into nature” or as passive recipients of philosophy’s spreading influence. In the third volume of his Paideia: The Ideals of Greek Culture, Reference JaegerJaeger (1944: 4–16) exemplifies this approach when he describes a three-stage process of mutual influence between medicine and philosophy: first, philosophy influenced medicine, then medicine philosophy, and finally philosophy and medicine fell in danger of being confused. “It was entirely natural,” Jaeger concludes, “that, when the great concepts of natural philosophy were taken over into medicine, its cosmological ideas should enter along with them and disturb men’s minds.” Jaeger’s characterization of cosmology as something that “entered into” medicine can be found in numerous accounts of the cosmological doctors. It has its roots in a modern tendency to distinguish “medicine” from “philosophy,” to separate “empirical” doctors, the supposed forerunners of positive science, from their more ambitious, “philosophical” colleagues. As one commentator writes in reference to On Flesh, “it is difficult to see that π. σαρκῶν is typically a ‘medical’ treatise, in spite of its self-description in its first sentence. It is certainly not concerned practically with medicine.”Footnote ⁴ Another says of On Regimen and On Flesh that they were written by “a new type of doctor, a very attractive type, because he tries to achieve avant la lettre a kind of symbiosis between positive science and philosophical thought.”Footnote ⁵ Many historians have described the cosmological doctors as sophists, “health experts” – anything but real doctors.Footnote ⁶ They were “under the influence of philosophy,” following its lead “to so great a degree as to interfere with and destroy the positive scientific outlook.”Footnote ⁷ In other words, the cosmological doctors were not just nonmedical; they were antithetical to medicine. Jones captures this sentiment when he writes that “During the fifth century B.C. philosophy made a determined effort to bring medicine within the sphere of its influence. … Medicine was here face to face with a deadly enemy.”Footnote ⁸

More recently, scholars have moved away from this narrative of a single, true “medicine” struggling against its enemies. Instead, it has been pointed out that “medicine” and “philosophy” were fluid concepts in the Classical period, and that any boundary between these two disciplines was liable to be crossed by doctors and philosophers alike.Footnote ⁹ In some cases, we see this overlap between “medicine” and “philosophy” explicitly mentioned in Classical Greek literature. In the Phaedo, Plato cites investigations into human physiology as an integral part of the “inquiry into nature” (96a–c). Elsewhere, he refers to Egyptians who study “everything concerning the cosmos down to divination and the art of healing that aims at health” (Ti. 24b–c). Aristotle twice notes that investigations “concerning nature” should conclude with the first principles of health and disease, while the best doctors tend to begin their inquiries with first principles derived from philosophy (Sens. 436a17–b1, Resp. 480b21–30). In On Ancient Medicine, the author complains about certain doctors and “sophists” who speculate about the fundamental constitution of human beings (20.1, 1.620 L.). Such speculations, he asserts, are not relevant to medicine but rather “tend towards philosophy, just like Empedocles or others who have written, concerning nature, what a human being is from the beginning, how it originally came to be, and from what it was compounded.” By arguing for a clear demarcation between medicine and “philosophy,” the author of On Ancient Medicine reinforces the idea that, at the time of his writing, such a demarcation did not yet exist. Anyone could give a speech, participate in a debate, or disseminate a text about “nature” (φύσις). The intended audience of such a contribution included both medical practitioners and educated laymen, who were in turn expected to develop their own opinions on whatever was being discussed.

This “fluid-boundary” explanation for the cosmological doctors stresses the sheer openness of intellectual discourse in the Classical period. It explains why Greek doctors were permitted to speculate about the cosmos, but it does little to clarify the precise origins, motivations, and methods of the doctors who sought out the first principles of all things. Even if we say that the Classical period saw no clear demarcation between “medicine” and “philosophy,” we do little to challenge the modern assumption that “philosophy” is still the most appropriate label for defining cosmological thinking. To cite one recent example, Reference BartošBartoš (2015) provides one of the most sensible analyses of a cosmological doctor to have appeared in modern scholarship. However, even he separates the “medical” and “philosophical” interests of his subject, observing that the author of On Regimen’s “elemental theory may seem obsolete from the dietetic and medical point of view … but regarding the tradition of philosophical inquiries into nature, it is an appropriate device for explaining natural processes” (98–99). For most historians of ancient thought, “philosophy” remains the preferred category for approaching the systems of the cosmological doctors. The upshot, of course, is that when these doctors are said to combine medicine with “philosophy,” it is still generally supposed that they are either undermining the former for the sake of the latter or else creating an amalgam in which the “philosophical” elements can easily be separated from the “medical.”

For my part, I prefer to avoid any reference to the cosmological doctors as practicing a “philosophical” brand of medicine. I do not object to this term on the ground that these physicians should not qualify as “philosophers.” Instead, I wish to stress that an equation between “cosmology” and “philosophy” oversimplifies what it means to investigate first principles. On the one hand, many participants in the inquiry into nature were devoted cosmologists, by which I mean their primary objective was to understand and describe the universe as a whole. However, cosmology can also be a framework for organizing and explaining other sciences, a mode of high-level thinking that elucidates phenomena by referring to the fundamental nature of all things. A doctor might take some principle from his clinical experience (e.g., hot compresses draw fluids from the body), compare that principle with other, nonclinical phenomena (e.g., the sun draws water from the sea), and further generalize it so that it applies not merely to the body but to the universe as a whole (e.g., heat attracts all fluids). If the doctor then applies this new principle to other, related aspects of clinical decision-making, we would say that he is thinking in “cosmological” terms. That does not mean, however, that the doctor has necessarily departed from a specifically “medical” mode of thought.

By equating cosmology with “philosophy” and by assuming that cosmological speculations are the exclusive purview of “philosophers,” we run the risk of ignoring what the doctors themselves might have brought to the table. Furthermore, if we assume that cosmology was simply imported into medicine, we are forced to choose between several unsatisfactory explanations for how the cosmological doctors came to be. It has often been asserted, for example, that the introduction of cosmology into medicine was unavoidable given the influence of the inquiry into nature. According to Reference FestugièreFestugière (1948: xix), “It was inevitable that the physicians of Ionia, in their investigation of the cause of the evils which afflict human nature, would have recourse to the theories elaborated by their compatriots concerning universal Nature.” Similarly, Reference LonieLonie (1981: 56) writes that “Greek speculative medicine could hardly avoid being governed, to a very large extent indeed, by the concepts and the categories of pre-Socratic philosophy,” implying that this movement was so transformative that Greek doctors could not help but be swept along with it. Some have attributed the entire phenomenon of cosmological medicine to the influence of one or more participants in the inquiry into nature. In these studies, one commonly finds references to supposed “schools” of cosmological medicine, whether they are Empedocles’s “Sicilian school” or even the “Eleatic school” of Parmenides and his followers.Footnote ¹⁰ It has also been popular to attribute the beginning of cosmological medicine to Alcmaeon of Croton, a shadowy figure who is sometimes presumed to have invented the definition of health as the balance between pairs of opposing powers.Footnote ¹¹ One problem with such great-man narratives, of course, is that the works of the cosmological doctors contain widely disparate opinions about the nature of the universe. If these doctors were simply followers of this or that cosmologist, we would expect their systems to have many more details in common. At the very least, we would expect them to engage in similar forms of cosmological thinking, but whereas some of these doctors focused on the material elements from which all things are composed, others simply speculated about the fundamental forces that have more “power” than anything else.

Some have suggested that the works of the cosmological doctors were influenced by Zoroastrianism or the Ayurvedic healers of ancient India.Footnote ¹² These suggestions, like other attempts to emphasize the influence of outside thinkers, are worthy of investigation when limited to particular details, but when they are used to explain entire systems, or even, in some instances, the entire phenomenon of cosmological medicine, they feed into a more general tendency to view cosmological medicine as somehow aberrant and therefore only explicable by pointing to some external origin. Reference GötzeGötze (1923: 79) justifies the supposed Zoroastrian origin of On Sevens (another work by a cosmological doctor) by observing that this text is “an erratic block in Hellas.” Reference WestWest (1971: 385–388), by contrast, stresses that On Sevens is “far from being an erratic block,” being “put together from parts that very obviously belong in a known tradition of speculation.”Footnote ¹³ West further adds that “In approaching the question of non-Greek material … we should not think in terms of any direct influence upon the work before us, but at most of the absorption of such material into a certain current of Greek thought at an earlier period.” Like other Greek thinkers from the Classical period, the cosmological doctors speculated about the universe in ways that have certain echoes in other cultures. That does not mean, however, that the entire phenomenon of cosmological medicine can be explained by simply pointing to these parallels. Even if we presume the transference of some ideas from one culture to the next, we would still need to explain the conditions that made these ideas attractive to Greek-speaking healers of the fifth and fourth centuries bce.

Other attempts to explain the cosmological doctors have simply listed all the benefits that come from cosmology: it is comprehensive, precise, persuasive, easy to teach, distinguishes one doctor from another, and so on. Building off of statements from On Ancient Medicine, Reference SchiefskySchiefsky (2005) endorses all of these points while further suggesting that the cosmological doctors could have been responding to outside criticisms that the “art” of medicine does not actually exist, which spurred them to give medicine the “starting point” (ἀρχή) and “method” (ὁδός) that would make it qualify as a genuine “craft” (τέχνη). As we will see, such concern for medicine’s status and methods was certainly a contributing factor to the rise of the cosmological doctors. However, a more precise explanation is needed to account for why these doctors would have taken their “starting points” all the way to cosmological principles. As for the idea that cosmology distinguishes one doctor from another, this explanation has been especially popular in modern scholarship, fostered by a heightened interest in the medical marketplace and in the physician’s basic need to persuade.Footnote ¹⁴ I find it difficult, however, to understand how a full-blown cosmology is more persuasive than, say, a detailed theory of human physiology, especially since cosmological principles were notoriously susceptible to differing interpretations and were therefore viewed with suspicion by many people in the Classical period. Cosmologists were parodied in comedy, accused of impiety, and ridiculed for speculating about matters that were invisible, irrelevant, and ultimately irresolvable. If the cosmological doctors were simply looking for more students, more patients, or a higher place in society, why would they select such a controversial framework as “the things on high and under the earth” for presenting their views on disease? It is of course possible, even likely, that the cosmological doctors were interested in propping up both their own reputations and the reputation of their art. Before we factor in such social pressures, however, we need to understand why these doctors considered cosmological principles a viable option in the first place.Footnote ¹⁵

The greatest shortcoming in all of these explanations is that they can be made with little knowledge of early Greek medical thought. In fact, they all treat medicine as a blank slate upon which new systems could be imposed. Medicine, of course, was not a blank slate. Greek doctors had their own traditional views on the etiology of disease, and they engaged in elaborate programs of medical inquiry in which they categorized phenomena in terms of commonalities and differences, universals and particulars at the same time that they speculated about the universe as a whole. To the best of my knowledge, no one has ever investigated how these preexisting theories and methods of inquiry may have contributed to the rise of cosmological doctors. In our haste to drive a wedge between medicine and “philosophy,” we have awkwardly separated the cosmological doctors from the rest of the medical tradition.

I.3 The Scope of This Study

In this study, I will examine the cosmological doctors from a medical point of view. In particular, I will argue that if we want to understand how this phenomenon came to be, we need to consider the changing priorities of medical thinking in the fifth and fourth centuries bce. By taking this approach, I do not intend to minimize or otherwise downplay the influence of the inquiry into nature on the cosmological doctors. Without a preexisting tradition of cosmological speculation, it is highly unlikely that this development would have ever taken shape. What I am stressing in this study is not that we should completely separate the cosmological doctors from other thinkers who inquired into the nature of all things. Rather, I intend to show that a simple gesture toward the inquiry into nature is insufficient for explaining how these doctors came to be.Footnote ¹⁶ In recent years, the monolithic edifice of “Presocratic philosophy” has given way to more specialized inquiries into the motivations and methods of individual thinkers. As a result, we are better able to understand how cosmological speculations were not simply a back-and-forth dialectic between self-identified “philosophers” but a multivalent mode of thinking that found reflection in many corners of Greek culture, a phenomenon that involved some fierce intellectual exchanges, to be sure, but that also needs to be placed within a broader range of social, religious, and cultural contexts. This study is a further step in the direction of complicating the old streamlined understanding of the inquiry into nature. It is not an investigation of medicine and philosophy but an exploration of what the cosmos meant to Greek doctors in the fifth and fourth centuries bce. Along the way, I will of course have many opportunities to draw connections between the cosmological doctors and other thinkers who speculated about the universe as a whole. As I hope to show over the course of this study, however, we will ultimately arrive at more interesting conclusions if we ask why the cosmological doctors thought they needed to describe the first principles of all things before we consider their reliance on the theories of other thinkers.

My analysis will be divided into six chapters and a conclusion. First, I will examine three secondhand reports: (1) the testimonies on Petron and Philistion in the Anonymus Londiniensis, (2) the speech of Eryximachus in Plato’s Symposium, and (3) On Ancient Medicine. I will then examine the four most important works by cosmological doctors to have survived from the Classical period: On the Nature of the Human Being, On Breaths, On Flesh, and On Regimen. For the sake of avoiding unnecessary distractions, I have chosen to omit any discussion of On Sevens. Nearly all the original Greek of this text has been lost, surviving only in a corrupt Latin translation.Footnote ¹⁷ In addition, there is significant disagreement about when On Sevens was written. Whereas some have dated the cosmological portion of this text as early as the sixth century bce, Reference MansfeldMansfeld (1971) has argued that it was actually composed half a millennium later, in the first century ce. To do this work justice would require a separate study in itself.Footnote ¹⁸ For a similar reason, I have also chosen to omit extended investigations into thinkers who have traditionally been grouped under the heading of “Presocratics.” Figures such as Empedocles, Anaxagoras, Diogenes, Democritus, Hippon, and Philolaus had much to say about the human body. Some of them even wrote separate works on the topic. However, my goal in this study is not to understand the place of anatomy, physiology, pathology, and therapeutics within the broader narratives of the inquiry into nature. Instead, my goal, as stated earlier, is to explore why some doctors for whom those topics were paramount felt compelled to also study the universe as whole. It would of course be interesting to come back to the inquiry into nature after arriving at a clearer picture of the cosmological doctors. It has been proposed that some figures such as Empedocles and Diogenes were practicing physicians, and it would therefore be interesting to compare their systems with the works presented in this study. It would also be interesting to think more generally about the intersections between cosmology and biology in the Classical period,Footnote ¹⁹ to explore the role of cosmology among medical writers of the Hellenistic and Roman periods,Footnote ²⁰ and to compare the Greek phenomenon of cosmological medicine with the healing traditions of China, India, and other ancient civilizations. These are all worthwhile topics, for which I hope the present study will offer some support, but to take full account of such issues would have necessitated a very different book.

In Chapter 1, I will start by clearing away some common misconceptions about the cosmological doctors. Most importantly, I will point out that an interest in cosmological principles does not preclude more traditional explanations of health and disease. Petron, Philistion, and Eryximachus all combine their first principles with lower-level discussions of the humors, pneuma, and the “powers” of food and drink. Instead of replacing humors with cosmic principles, these doctors constructed multitiered narratives of pathogenesis, placing humors and cosmic principles at different points in the causal chain.Footnote ²¹ I will also point out that we can better understand some of the more obscure aspects of these doctors’ systems (e.g., Eryximachus’s reference to a “healthy” and a “diseased” eros that exist within the body and are nourished by different things) by considering preexisting, widely attested beliefs about human physiology. After establishing this connection between more traditional theories of pathogenesis and the speculations of the cosmological doctors, I will then demonstrate that the polemical On Ancient Medicine is an unreliable witness to what the cosmological doctors were doing. Whereas the author of this text claims that the prioritizing of such principles as the hot and the cold is incompatible with the attribution of diseases to the humors, I will show that the cosmological doctors were in fact more than comfortable with combining first principles with more traditional beliefs about the body.

After making this observation, I will then turn in Chapter 2 to consider the relationship between cosmological principles and clinical decision-making. If the cosmological doctors still attributed diseases to substances like the humors, how did they incorporate cosmological principles into their systems of treatment? My investigation of this question will center around On the Nature of the Human Being, whose author I identify as Polybus of Cos. In this text, Polybus claims that the humors, like everything else, are composed of four primary substances: the hot, the cold, the dry, and the wet.Footnote ²² Polybus further claims that changes in these four qualities are responsible for the ebbing and flowing of four humors in the body, and that diseases can be prevented by treating “opposites with opposites”; that is, by counteracting the hot with the cold, the cold with the hot, the dry with the wet, and the wet with the dry. After establishing this theoretical framework, Polybus then appends a series of chapters that primarily focus on the topic of humoral flux. “Flux” is the idea that a single humor, after gathering in one part of the body, can create a wide range of effects by flowing to different parts. In this chapter, I will argue that Polybus’s thinking about cosmological principles is closely tied to his interest in humoral flux. Both concepts are motivated by an interest in tracing diseases to their “source” (ἀρχή), and both ultimately establish a two-pronged approach to treatment, wherein doctors are expected to target both the proximate cause of a disease (i.e., a concentrated humor) and its remote cause (i.e., the factor(s) that initially caused that humor to separate out). Within this causal framework, the treatment of “opposites with opposites” is only applied to a disease’s remote cause. The proximate cause, meanwhile, is still treated by identifying and then purging harmful humors from the body. In the final section of this chapter, I will observe that Polybus’s emphasis on tracing diseases to their “source” is also tied to a more general interest in commonality and difference. Polybus is deeply interested in the many variables that can change from one case to the next, believing that treatments should be adjusted to the age, sex, habits, and physical constitution of the patient, the geographical location, the season of the year, and the fashion of the disease. However, such an interest in individual differences does not preclude a coexisting interest in cosmological principles. Instead, Polybus presents his cosmological principles as a solution to the problem of individual variation, identifying the shared “nature” (φύσις) of human beings as a high-level commonality that transcends individual differences.

In Chapter 3, I will apply these lessons from On the Nature of the Human Being to the supposedly “radical” thesis of On Breaths. I will argue that the author’s attribution of all diseases to pneuma is not as revolutionary as it initially appears. By relying on widely attested views about what pneuma tends to do within the body, this author is in fact remarkably conservative when constructing his own theories of pathogenesis. After making this point, I will then turn to the more important question of why this author felt compelled to identify a single cause of all diseases. On the one hand, we can point to the same interest in remote and proximate causes that we see in On the Nature of the Human Being. So many diseases are caused by pneuma, which naturally flows through the vessels and is the primary agent of bodily change, that the best way to ward off an illness is to remove anything that introduces noxious pneuma into the body. In this way, the author resembles Polybus in his application of cosmological principles to the remote cause of a disease, while the proximate cause does not deviate from more familiar narratives of pathogenesis. We should therefore resist the modern tendency to place On Breaths outside the “mainstream” of the Hippocratic Corpus; this author’s views are not as radical as they often are portrayed. Of course, the otherwise practical consideration of remote and proximate causes does not explain why the author of On Breaths emphasizes the universality of his principle, and it also does not justify his more general assertion that pneuma is the most powerful force in the universe as a whole. On these points, the author seems to be driven by a separate “cosmological impulse,” the belief that high-level commonalities, whatever their applicability, are inherently desirable and directly relevant to the medical art.

Chapter 4 addresses the central question of this study: how did cosmological medicine come to be? In this chapter, I will argue that the cosmological doctors arose as the result of a much wider realignment in Classical Greek medicine. As some doctors grew increasingly concerned about the many variables that can change from one case to the next, they rejected older forms of diagnostic handbooks in favor of new methods for organizing medical knowledge. We see this anxiety over individual differences not only in the works of the cosmological doctors but also in texts such as On Regimen in Acute Diseases, Prognostic, Airs Waters Places, and the seven books of Epidemics. In all of these texts, medical inquiry is defined, quite generally, as a search for commonalities. Doctors in this period were gathering together multiple accounts, noting the similarities and differences between those accounts, and isolating high-level generalizations that can unite and govern them all. Although the cosmological doctors took their search for commonalities farther than some of their contemporaries might have been willing to follow, they nevertheless responded to the same pressures that transformed nearly all the medical literature that survives from this period. Various social factors may have further encouraged some doctors to be more enthusiastic about their generalizations than others, but the very urge to generalize came from a research program that explicitly defined medical inquiry as the search for what is “common,” a program that was itself driven by a central problem in clinical decision-making: the need to attain “precision” (ἀκρίβεια) when no two patients are exactly alike.

After providing this explanation for how the cosmological doctors came to be, I will turn to consider the details of their systems. In Chapter 5, I will propose solutions to some longstanding problems surrounding the anthropogony of On Flesh. First, I will show how the author’s three main principles of the hot, the cold, and the wet reflect widely attested beliefs about the effects of heat and cold on bodily fluids. After that, I will argue that the author’s two supplementary principles of the “fatty” and the “glutinous” are derived from a traditional dichotomy between bile and phlegm. The upshot of these observations is that the author of On Flesh uses the microcosm of the body as a tool for understanding the macrocosm of the universe. For this author, the natural world is primarily a reflection of the body (not the other way around), and it is specifically medical knowledge that gives him insight into the cosmos. Just as Eryximachus claims to have acquired his awareness of the universal power of eros “from medicine, our art” (ἐκ τῆς ἰατρικῆς, τῆς ἡμετέρας τέχνης, 186a), so the other cosmological doctors viewed medicine as a privileged starting point for contemplating the universe as a whole.Footnote ²³

In Chapter 6, I will conclude this study of the cosmological doctors with a wide-ranging consideration of On Regimen. This text is the longest and by far the most complex work by a cosmological doctor to have survived from the Classical period. Over the course of this chapter, I will show that On Regimen is a highly regular, unified, and richly detailed text. My most significant contribution will regard the author’s views about divinity. As we will see, this author seems to consider the heavens to be the source of all souls within the universe. Anything that engenders either intelligence or movement is merely an emanation of this cosmic soul, and it represents a unitary god from which all other divinities branch off. A brief consideration of this author’s affinities with other thinkers will reinforce this interpretation. It will also illustrate how this understudied text can provide an invaluable lens for broadening our understanding of early Greek cosmology. As a medical writer, the author of On Regimen responded to pressures very different from what we see among other cosmologists. Nevertheless, he seems to have been deeply engaged with contemporary thinking about the cosmos, and therefore should serve as a helpful reminder that the Hippocratic Corpus is a critical resource for any student of Greek thought.