Aistė Čelkytė’s Galen on Human Physiology is a wide-ranging study of the Galenic body, offering a thorough treatment of Galen’s physiology. Rich in detail, the book offers a synoptic account of a vast and difficult corpus. This strategy produces an unusually unitary Galen, though at the cost of eliding some of the tensions of his multifarious thought.
The introduction frames the book in two ways: first, as a study of Galen’s “phusiologia,” and then as a study of Galen on vital parts and vital wholes. These two projects, Čelkytė argues, coincide. At least some of the time, phusiologia names for Galen the task of “tak[ing] the body apart” and then “put[ting] it back together” (p. 12): dividing and taxonomizing the parts of the living body and understanding how they function in unison to produce a singular life.
Chapter one presents a systematic overview of Galen’s theory of “parts.” Čelkytė convincingly identifies the targets of Galen’s polemics against other mereologies (namely, skeptics, Theophrastus, pneumatics). In place of these, Galen has his own theories of parts, two of them, in fact. The first is a contrast between parts that have a distinctive role to play in a function (structured parts) and parts that are interchangeable with other parts (homoiomeries). The second distinguishes parts according to the role they play in executing the body’s physiological functions: principals (which govern other parts), governed by principals, self-sufficient, self-sufficient and governed by principals, or—like hair and nails—without any role in the body’s functions. The end of the chapter supplies the logic underlying both Galen’s polemic against others and his counterproposals. Galen’s theory of body parts, Čelkytė argues, is oriented towards the fullest possible understanding of the body’s interlocking functions, informed by the view that medicine must engage the body’s (often imperfect) functionality rather than its “theoretical perfection” (pp. 50–51).
Chapter two opens with a discussion of nutrition, emphasizing the role of the liver and introducing the reader to Galen’s distinctive physiological model of “natural capacities.” It then proceeds to growth, which Čelkytė argues is “closely connected” to nutrition (p. 72), since it depends in part on the same “alterative capacity” responsible for nutrition. But embryological growth requires something more: not only an “alterative capacity” able to make more of what is already there, but also a “formative capacity” able to generate something new. Čelkytė proposes that two distinct demiurgic powers are at work in Galen’s account of embryological formation, each corresponding to a different meaning of “demiurge”: “nature” (or the vegetative soul) and the divine Demiurge of Middle Platonism. For the latter, Galen is indebted to Middle Platonism’s creator god; for the former he is indebted to a specific deflationary usage in Aristotle’s biology, which identifies the most “active” body part in any physiological process as a “demiurge.” In each person, Čelkytė argues, “nature” performs minor demiurgic work, while the divine Demiurge intervenes to perform the genuinely creative work of sculpting the body’s nonhomogeneous parts.
Chapter three is a discussion of “vital capacities.” The first half covers the physiological processes of respiration and “transpiration” (skin breathing), including a thorough treatment of the question of why Galen understands respiration to be voluntary. The second half covers the types of pneuma and the role that each plays in the functioning of the body. While the discussion of pneuma helpfully consolidates scholarship on this issue, it does not depart significantly from Armelle Debru’s foundational study Le Corps Respirant.[1]
Chapter four, covering the nervous system, proceeds from Galen’s claim that the nerves have three functions: voluntary motion, pain, and sensation (plus an occasional fourth, to “knit together” the body). Čelkytė explains that the difference between motor and sensory nerves is fundamentally a difference in their texture (motor nerves are harder, sensory nerves more fine). She then proceeds to a discussion of the significance of pneuma to the nervous system, again emphasizing its texture. She offers a brief overview of how voluntary movement works in normal cases, as well as a review of Galen’s “problematical cases.” Next come Galen’s multiple accounts of pain, then perception, proceeding from the case of internal perception (relevant to pain) to the case of external perception. The account of internal perception leads to a lucid reflection on Galen’s analogies between animals and organs (p. 169). Finally, Čelkytė unpacks Galen’s argument against Herophilus regarding the “inherent sensitivity of the nervous tissue.”
In the final chapter, Čelkytė “puts the body back together”: that is, she examines the integration across the three systems of the body. Čelkytė seeks a definition of life that can account for its emergence from the dynamic interaction of these three systems. Following an interesting digression on the deflationary usage of “form” in Galen, Čelkytė proposes that the best way to understand Galen’s theory of vitality is not in Aristotelian terms, but rather through the Stoic model of cohesive cause.
Among the original and exciting insights that emerge from this examination of Galen’s physiology is the importance of texture.[2] In Chapter three, Čelkytė explains that the pneuma plays a key role in vital functions because of its hypersensitivity to heat. It is thanks to the mediation of the pneuma, she shows, that the animal body can be so much more dynamic than the plant body: it moves from head to toe with the characteristic bidirectional movement upward and downward produced by the innate heat. This observation is picked up again at the end of the following chapter on nerves (p. 180). This treatment of texture is a rich and compelling payoff from Čelkytė’s mereological approach to Galen’s physiology.
At times, the book’s commitment to Galen’s consistency threatens to overtake its more granular work of textual interpretation, as in the discussion of embryological formation, “natural pneuma,” or Stoic cohesive cause. Čelkytė tends to downplay the fact that Galen himself—a writer hardly given to modesty—persistently admits to certain areas of aporia: for instance, on the substance of the soul or embryological formation. In the latter case, for instance, Čelkytė dexterously makes sense of the range of ways Galen uses the phrase “demiurge.” But the sharp distinction she draws between the creative agency of the Demiurge, on the one hand, and the minor demiurgy of blood and seed, on the other, undersells Galen’s own persisting difficulties disentangling the two (e.g. in Mixtures I.566-567K, Formation of the Fetus IV.699-700K). Indeed, the tendency to minimize aporia is characteristic of her approach. Compare, for instance, Čelkytė’s more confident account of Galen on respiration and transpiration with Debru’s observation: “consideration of the way in which flames are extinguished through lack of air allows [Galen] to express his lack of certain knowledge in this context.”[3]
Second and related, Čelkytė’s Galen seems curiously decontextualized from either his contemporaries, who rarely feature, or from any intellectual lineage. Čelkytė describes Galen’s interlocutors and influences, including Erasistratus, Aristotle, Galen’s contemporaneous rivals, and the Hippocratics, largely in the terms with which Galen himself describes them. Of a piece with Galen’s own rhetorical strategy, Čelkytė often emphasizes the Hippocratic background even where there is good reason to think the relevant background is in fact Aristotelian.[4] And when Čelkytė does discuss Galen’s predecessors more broadly, it is generally to emphasize that Galen “build[s]” (p. 159) on their approaches, not to draw attention to the tensions that result from Galen’s borrowing from and integration of an enormous range of sources (“Galen uses the medical inheritance philosophically,” p. 117) or the revisions this necessitates. The result can be to flatten Galen’s engagements with his predecessors to simple “inheritance” and agreement. There is little, here, for instance, on the potential for tension between Galen’s Hippocratism and his Aristotelianism, or recognition that Galen’s style of citation is part of his practice of argumentation.[5]
These issues reflect a larger problematic of method. Galen on Human Physiology offers up a maximally unitary, consistent version of Galen, for whom physiology is a single mereological project. This effort to reconcile Galen’s heterogeneous corpus presents a bold, intriguing provocation. But Čelkytė’s framing discussion does not make an affirmative case for this program—in large part since it does not address Galen’s own statements about the organized heterogeneity of his corpus. After all, at key moments throughout the corpus Galen tells his readers that the human body must be understood at three levels: elements/qualities, mixtures, and nonhomogeneous parts (e.g. The Best Doctor Is Also A Philosopher I.60K; The Best Constitution of the Body IV.740-741K) and stipulates a reading order for his works based on these “levels of explanation.”[6] Many foundational (mostly article-length) studies of Galen on physiology begin from this observation (e.g. Singer; van der Eijk).[7] By downplaying the fact that she is reading against the grain, Čelkytė makes it harder to assess the payoffs and limitations of her approach.
Čelkytė puts the corpus of Galen and also the Galenic body back together with impressive thoroughness. She knits together a tremendous range of his writings, drawing into dialogue their discussions of the body. And she reads Galen unapologetically for what he can teach us about Galen, refreshing in the case of an author still often mined primarily for what he can contribute to thematic or historical studies. Still, to paraphrase Herodotus, no body (or corpus) is autarchic. Lost in the vision of a cloistered Galen are the rhetorical games, strategies, and misprisions that characterize Galen’s handling of his predecessors, rivals, and contemporaries, as well as the organized heterogeneity of Galenic physiology and the multiple levels of the Galenic body.
A corpus the size of Galen’s offers no obvious answers to the question of how it should be studied both in its own right and in its relations to other phenomena. Čelkytė has given us one approach, ambitious and detailed. It will, I hope, serve as an important stimulus to the ongoing work of disassembling and reassembling the Galenic corpus/body on fresh terms.
Notes
[1] Armelle Debru, Le Corps Respirant, La pensée physiologique chez Galien. Studies in Ancient Medicine, 13 (Brill, 1997).
[2] “Texture” here signifies the thickness or lightness of a given part (e.g. παχύς; πυκνός; λεπτομερής; λεπτός).
[3] Armelle Debru, “Physiology” in R.J. Hankinson, ed., The Cambridge Companion to Galen (Cambridge University Press, 2008), 277.
[4] On this strategy in Galen see Philip van der Eijk, “‘Aristotle! What a thing for you to say!’ Galen’s engagement with Aristotle and Aristotelians” in Christopher Gill and Tim Whitmarsh, eds., Galen and the World of Knowledge (Cambridge University Press, 2009), 261–281.
[5] E.g. Rebecca Flemming, “Commentary” in R.J. Hankinson, ed., The Cambridge Companion to Galen (Cambridge University Press, 2008), 323–354.
[6] Peter Singer, “Levels of Explanation in Galen,” Classical Quarterly 47, no. 2 (1997), 525–542.
[7] E.g. Singer 1997; Philip van der Eijk, “Galen on the Nature of Human Beings,” Bulletin of the Institute of Classical Studies. Supplement, no. 114 (2014), 89–134.