CHAPTER TWO JEAN FERNEL AND HIS CHRISTIAN PLATONIC INTERPRETATION OF GALEN 1. Introduction Throughout his entire career, Galen of Pergamum (129–ca. 216) refrained from delivering his defijinitive answer to the major questions addressed in the tradition of Greek philosophy. These questions concerned the substance of the soul and the essence of the demiurge or God. Galen’s attitude, called “agnosticism” by modern scholars and recognized as char- acteristic of his philosophy, was based on deep reflections and a long scientifijic quest which dominated his activity.1 Once the entirety of Galen’s immense corpus became available in Renaissance Europe, university physicians concentrated on reconstruct- ing his medical system through a philological method typical of humanist culture. But they often left aside the problem of its compatibility with Christianity. The interpretation of the medical humanists, especially that of the Paduans, tended toward naturalism or physicalism, if not material- ism. The bitter reaction of the Swiss physician Paracelsus (ca. 1493–1541) to this trend is well known. By following a marginal path, he stayed out- side the academic system. His effforts initiated a dynamic movement of chemically-oriented medicine, which was to bloom in princely courts and private academies at the threshold of the Scientifijic Revolution. Remaining in the traditional institutional framework, however, some intellectuals tried to reconcile the new Galen of the medical humanists 1 On his agnosticism, see Paul Moraux, Der Aristotelismus bei den Griechen von Andron- ikos bis Alexander von Aphrodisias (Berlin, 1984), II: 785–91. The question of the soul is related to his attitude toward Platonism. On this issue, see Phillip De Lacy, “Galen’s Platonism,” American Journal of Philology 93 (1972), 27–39; Peter N. Singer, “Aspects of Galen’s Platonism,” in Galeno: obra, pensamiento e influencia, ed. Juan A. López Férez (Madrid, 1991), 41–55; Teun Tieleman, “Galen’s Psychology,” in Galien et la philosophie, ed. Jonathan Barnes et al. (Geneva, 2003), 131–61. On his medical philosophy, see Rudolph E. Siegel, Galen’s System of Physiology and Medicine (Basel, 1968); Owsei Temkin, Galenism: Rise and Decline of a Medical Philosophy (Ithaca, 1973); Armelle Debru, Le corps respirant: la pensée physiologique chez Galien (Leiden, 1996). I have used the edition by Karl G. Kühn, Galeni opera omnia, 20 vols. (Leipzig, 1821–33; repr. Hildesheim, 1965). jean fernel 47 with the Christian faith.2 The case of the French physician Jean Fernel (1497–1558) is most remarkable because of the considerable influence he exerted on his contemporaries and on later generations. Thanks to a good reputation of his practice in the medical faculty of Paris, his ideas circu- lated all over Europe through his successful writings.3 For Fernel the “mate- rialism” of the medical humanists, whom he called “Averroists” (without mentioning any specifijic names), was gravely erroneous. To remedy this crisis, he especially called upon Christian Platonism, a philosophical cur- rent which developed during the last decades of the fijifteenth century in Florence around the fijigure of Marsilio Ficino. The chief result of Fernel’s endeavor was his treatise On the Hidden Causes of Things (De abditis rerum causis). Structured as a dialogue among three friends, Eudoxus, Brutus and Philiatros, this work was probably composed at the same time as his On the Natural Part of Medicine (De naturali parte medicinae) (Paris, 1542), more famous under the title of its second edition, Physiology (Physiologia). Fernel continued to rework De abditis until its publication (Paris, 1548) and further revised it for the second edition (Paris, 1551). These two trea- tises form an inseparable pair fundamental to his medical system. While the Physiologia deals with the natural and visible fijields, its counterpart De abditis takes up the invisible, therefore more abstract and philo- sophical, realms. Thus the dialogue on the hidden causes of things is not a juvenile product as some historians have judged, but a seri- ous, mature work. There Fernel repeatedly complains that the human mind is overwhelmed by visible and superfijicial aspects, owing to the four traditional elements, and by people’s deep-seated ideas which are difffijicult to escape. His primary goal in this treatise is the quest of “the divine” (to theion) in natural and medical philosophy, a notion evoked at 2 On the Christianization of Galen in the Middle Ages and onward, see Vivian Nutton, “God, Galen and the Depaganization of Ancient Medicine,” in Religion and Medicine in the Middle Ages, ed. Peter Biller and Joseph Ziegler (York, 2001), 17–32; idem, “Biographical Accounts of Galen, 1340–1660,” in Geschichte der Medizingeschichtsschreibung: Historiogra- phie unter dem Diktat literarischer Gattungen von der Antike bis zur Aufklärung, ed. Thomas Rütten (Remscheid, 2009), 201–32. 3 On his life and work, see Dictionary of Scientifijic Biography 4 (1971), 584–86; Léon Figard, Un médecin philosophe au XVIe siècle: étude sur la psychologie de Jean Fernel (Paris, 1903); Charles Sherrington, The Endeavour of Jean Fernel (Cambridge, 1946); Jacques Roger, Jean Fernel et les problèmes de la médecine de la Renaissance (Paris, 1960); Massimo L. Bianchi, “Occulto e manifesto nella medicina del Rinascimento: Jean Fernel e Pietro Severino,” Atti e memorie dell’accademia Toscana di scienze e lettere 47 (1982), 183–248..