Jessica Wright, Brain and Soul in Late Antiquity, (Ph.D. Classics, Princeton University, 2016).
In the late fourth century CE, the Greco-Syrian bishop Nemesius of Emesa described what was to become the earliest surviving account of ventricular localization—that is, the localization of discrete psychic faculties in hollow spaces (or “ventricles”) within the brain. Nemesius was almost certainly not the originator of this idea, which he probably borrowed from the contemporaneous medical author Posidonius of Byzantium, whose own works have not survived. Yet, Nemesius’s account of ventricular localization was to prove foundational in the dominant theories of brain function that developed within Arab-Islamic and European medicine. Much as contemporary neuroscientists and even historians of medicine might dismiss the contribution of early Christian theology to our understanding of the human mind, modern theories of cerebral localization are genealogically related to Nemesius’s account of the brain.
Nemesius is typically cited (sometimes together with Augustine, who offers a similar theory) as the earliest witness to ventricular localization. Yet, historians of late antiquity have rarely noted the importance of Nemesius either as a medical authority or as a philosopher—for the most part, indeed, Nemesius has been dismissed as unoriginal. Most scholarship on his only extant work, the philosophical and theological treatise, On the Nature of the Human Being, has focused on plumbing the text for quotations of and references to earlier authorities. Historians of the brain, meanwhile, have not examined Nemesius’s account of ventricular localization within its cultural context: their interest lies in how his account shaped later brain science, rather than in discerning the scientific and cultural influences that shaped what Nemesius thought.
My dissertation, Brain and Soul in Late Antiquity, examines early Christian engagement with the medical concept of the “brain” (Gk. enkephalos, Lat. cerebrum). It focuses on two questions in particular: What was the role of the brain in early Christian conceptions of the human being, both body and soul? And, how did early Christian theories of and concern for the soul shape the history of the brain?
The brain was recognized in late antiquity as the chief bodily instrument of the soul, functioning through the movement of pneuma (spirit) through its ventricles to the sensory and motor nerves that were rooted in the brain. As such, the brain stood at the interface between material and immaterial worlds, enabling the embodiment of the soul and the fulfillment of its thoughts and its desires. In this capacity, the brain represented in condensed form the human being, which was similarly suspended between material and immaterial qualities, earthly and divine.
As the organ of governance and reason, the brain was central to early Christian anthropology. Here it served as both a resource and a challenge. The brain could help to explain the relationship between body and soul, but it could also threaten to overtake the psychic functions and so render the soul theoretically superfluous. Medical accounts of the brain as the seat of cognitive and sensorimotor function also challenged scriptural emphasis upon the heart, leading early Christian authors to negotiate between scientific and scriptural authority about the human body. Tertullian simply denies the authority of contemporary doctors. Jerome and Lactantius give key functions to both brain and heart. Augustine exercises his exegetical ingenuity to interpret the “heart” of scripture as different from the heart that we see when opening the body of an animal, that is, as a figurative reference to the soul or mind.
Yet, the brain was also useful, as both a conceptual and an imaginative resource. Medical theories about the brain and its response to alcoholic vapors helped preachers such as John Chrysostom explain how diet and drink could affect the soul. As the organ of governance within the human body, the brain provided a model for imperial authority, for ecclesial administration, and for the lordship of God. The familiar metaphor of Christ as the head of the church could be re-interpreted to suggest that Christ was a brain, feeding spirit to the members of the body through the sensory and motor nerves. Ventricular localization prompted theorists of the soul, choosing their words carefully, to identify bodily instruments that the soul might use to, for example, remember a perception, while avoiding the possible implication that the soul itself could be trapped inside the brain. Figurative and philosophical engagement with the brain across a wide range of texts—letters, homilies, tractates, and poems—reflects in fragmentary form the pervasiveness of the brain in popular and learned understandings of what it meant to be a human being in the early Christian world.
Chapter one of the dissertation surveys ideas about the “brain” (enkephalos) in the Greek philosophical and medical traditions, beginning with pre-Socratic authors (sixth century BCE) and concluding with Galen of Pergamum (second century CE), whose account of the brain was to become canonical in late antique and medieval medicine. The chapter traces the trajectory through which the brain emerges as the organ of the hêgemonikon (the governing part of the soul), but it also emphasizes the importance of alternative accounts. In Hippocratic and Aristotelian texts, for example, the brain was fundamentally an organ of balance, responsible for absorbing and releasing excess bodily fluids (especially phlegm) in order to stabilize the temperature and humidity of the body as a whole. Although Galen marginalizes this aspect of brain function in his arguments for the psychological importance of the brain, early Christian authors reveal continued interest in the brain as a site for the accumulation of vapors and fluids. This chapter lays the foundations for interpreting the diverse references to the brain in early Christian texts as reflective of diversity in the intellectual tradition.
Chapter two turns from “scientific” to “theological” accounts of the brain function, highlighting in these accounts early Christian concerns regarding the relationship between body and soul. Identifying three basic models for the body/soul relationship (body as instrument; body as container; soul as temperament or attunement), I show how anxiety about the implications of each model for the integrity of the soul as immortal and transcendent plays out in early Christian theorization of the brain. Gregory of Nyssa, for example, rejects the idea that the brain is the seat of the mind on the grounds that this would require theorizing a material soul that could be trapped or expelled through bodily affection. Isidore of Pelusium mixes his metaphors in a confusing sequence of images that culminates in a steersman-turned-musician throwing himself and his lyre into the sea—all in order to avoid putting the soul at the mercy of its body. Even ventricular localization, the argument that discrete psychic faculties are associated with ventricles within the brain, might more accurately termed “ventricular instrumentalization,” since—unlike later medieval authors and modern commentators—Nemesius of Emesa insists that the ventricles are instruments of, rather than containers for, the faculties of the soul.
Whereas the first two chapters focus on explicit theorization of the brain, chapters three and four examine practical applications of brain theory in pastoral contexts. Chapter three investigates the rhetoric of cerebral vulnerability that dominates references to the brain in Christian homilies and sermons. Early Christian preachers emphasize the vulnerability of the brain to physical blows, odors, and bodily fluids or vapors. This vulnerability was common medical knowledge—the brain was soft, for example, to allow for sensation; hangovers, meanwhile, were thought to be caused by the impact of alcoholic fumes upon the brain. In highlighting cerebral vulnerability, preachers demonstrate a general knowledge of medical teachings about the brain that they must have assumed would be recognizable to their audiences.
Cerebral vulnerability also proved to be pedagogically useful. John Chrysostom, for example, uses the susceptibility of the brain to vapors in order to encourage his congregants to conform to particular kinds of bodily discipline—abstention from wine, in particular. In discussions of providence, the softness of the brain provided the motivation for the providential design of the skull, demonstrating the necessity of divine protection over the rational-but-weak human being. When the governing aspects of the brain came into the foreground, the vulnerability of the brain to the activities and condition of the body as a whole represented the oft-times rocky relationship between the emperor and his populace. As the physician of the soul, the bishop or priest might also intervene therapeutically in this relationship, acting as ambassador to the imperial court, while soothing and chastising the people under his care. The vulnerability of the brain provided a model for charting the increasingly politicized role of Christian preachers.
Chapter four investigates a different aspect of cerebral vulnerability: its usefulness as a model for sickness of the soul. Examining the resonances between various accounts of the brain disease phrenitis (hagiographic and polemical, medical and homiletic), I show how phrenitis functioned in early Christian discourse about orthodoxy and salvation to limit individual ascetic excellence and self-reliance in spiritual affairs.
In late antiquity, phrenitis was understood to manifest as acute delirium and acute fever, caused by inflammation of the membranes surrounding the brain. Characteristic symptoms included hallucinations, the appearance of preternatural strength, and violence against oneself, one’s attendants, and even one’s physician. As such, phrenitis provided an excellent model for a sickness of the soul characterized by the false experience of spiritual strength and resistance to therapeutic intervention. This was precisely how Augustine diagnosed a range of different religious positions, each of which shared in common their deviation from Augustinian Christianity. In his sermons, Augustine diagnoses Jews with phrenitis, on the grounds that Jews do not recognize that they are sick, and so reject and attack the physician of the soul that is Christ. In letters to imperial administrators, he diagnoses Donatists with the same illness, since Donatists assume their own spiritual purity (read, health) and similarly reject the intervention of Catholic preacher-physicians. In a treatise on widowhood, he warns a wealthy widow not to follow the Pelagians into celibacy, since “no one wants to suffer from phrenitis, even if she should see that the person suffering from phrenitis has greater strength than those in full health.” Even asceticism, if in excess, might be interpreted as a symptom of brain fever, that is, as a mental illness that manifests the experience of health.
Little attention has been devoted to the brain in the early Christian thought world. Yet, the brain was central to late antique anthropology, and was fruitfully appropriated in theoretical and pastoral texts as fourth- and fifth-century Christian authors sought to assert their epistemological authority over the human body and its relationship to the soul. The “cerebral subject” might be the product of neuroscience and early modern philosophy, but its roots go much further back to antiquity, in the encounter between emergent Christian theories of the soul and entrenched medical understandings of the brain.
Dr. Jessica Wright is a Post-Doctoral researcher in the Society of Fellows at the University of Southern California. Further discussion of her research on the discourse of "crazy" in Augustine can be found here. She is currently turning her dissertation into a book.