Galenism: Rise and Decline of a Medical Philosophy
Galen of Pergamum elaborated his medical philosophy during the second half of the second century AD, and was the dominant influence on medical thinking until the eighteenth. He was at the same time an experimental scientist, a medical practitioner, and a commentator. Before being doctor to the emperors in Rome, where he died, he was surgeon to the gladiators in his home town of Pergamum in Asia Minor. In his writings he speaks as the equal of Hippocrates, Plato, and Aristotle, praising and criticizing them by turns. If in many respects he was an epigone who selected from the immense heritage of his predecessors, he nevertheless codified their wisdom for succeeding generations, making considerable improvements in their views of anatomy and physiology.
He includes in his system ideas taken from Hippocrates, particularly the doctrine of the four humors. Where one of the most influential Hippocratic treatises, “On the Nature of Man,” held that four body fluids, or humors—blood, phlegm, black bile, and yellow bile—determined health, Galen extends this theory and speculates freely on different mixtures of the humors and types of temperament related to them. Galen also borrows from Plato the tripartite division of the soul into the rational, the passionate, and the concupiscent. Like Aristotle he believes that nature produces nothing in vain and explains the structure of each organ by its own final cause, and he follows the Stoics in attributing to the cosmic pneuma—an airlike substance—a primordial role in breathing and the conservation of life.
All these ideas, though they may not always cohere perfectly with one another, were organized and related by Galen in a way that both satisfied the demands of speculative logic and could be confirmed by sense experience. His system has survived in a large number of treatises, some better preserved than others, and these are only a part of his complete works. Each of these treatises merely develops one element in his vast scheme of medical philosophy, which we have reason to believe was constantly reshaped by its author to accommodate new observations and changing convictions. But the systematizing urge was already sufficiently strong in Galen for the Arab world and the European Middle Ages to give his doctrine a closed dogmatic form without feeling that they were distorting his thought. No doubt he owed his prestige to this excessive systematization; thanks to this his doctrine became the standard textbook of medicine, almost up to the final collapse of Aristotelian physics in the sixteenth and seventeenth centuries.
Nor did Galenism drop dead all at once. It was a vast edifice which only gradually crumbled away. It is not difficult to see in the writers who criticized the conservatism of Galenic orthodoxy considerable traces of the very doctrine they were attacking. Molière mocks his substantial qualities (the “dormitive virtue” of opium) and laughs at the “anticirculation” doctors who did not recognize Harvey’s discovery, but when he creates his misanthrope he makes him a melancholic, and his Tartuffe is a sanguine—in a word, Molière remains faithful to a notion of the temperaments which goes back by way of the standard formulas and systematic popularizations to Galen and more specifically to Galen’s commentary on Hippocrates. Toward the middle of the nineteenth century, at a time when Galen’s name was mentioned by no one but historians, there were still psychiatrists who asserted that the suppression of hemorrhoidal fluxes, of menstrual bleeding or of skin rashes, could cause a manic attack—and this relic of Galenism took some time to die out. So there was a considerable residue, but still only a residue.
One can see what a range of knowledge is needed to write the history of Galenism from its origins to its down-fall; the writer must be familiar with several cultures, and in addition must be able to assess the relations between different fields of learning which were once not separated by our disciplinary barriers: philosophy, cosmology, natural science, theology, literature, etc. Professor Owsei Temkin of Johns Hopkins is one of the few scholars of our time who could deal with so vast a subject, Going directly to the Greek, Latin, and Arabic sources, as well as to the mass of European medical literature, Temkin manages to bring to light the principal turning points in the transmission of Galenism, its social and religious implications, and the stages in its decline. Points of detail are dealt with in a substantial body of notes and a thirty-five-page bibliography quotes all that has been written on the subject.
In these four lectures (the 1970 Messenger Lectures at Cornell University) we find the simplicity and modesty of tone which is the prerogative of those who are completely in command of their subject and are thus best able to tell what in the present state of knowledge are the limits of our information, where further investigations are called for, and which of our conclusions still remain hypothetical.
For the historian of ideas the long history of Galenism is a perfect subject. It calls for an investigation both of the doctrines of a system and of the way it was received over a period of thirteen centuries. While we must naturally take into account what Galen’s system says, together with the various modifications of which it showed itself capable, we have also to take note of the way it was listened to, that is to say the function it fulfilled in the various milieux and institutions which accepted its authority. And finally, as with any doctrine which enjoyed a period of lasting supremacy before being eclipsed, we need to ponder the circumstances which led to its discredit and collapse; in such a post-mortem we cannot avoid characterizing it by contrast with the system which conquered and replaced it.
In his excellent account of Galen’s main ideas Owsei Temkin gives full weight to the notion of “cumulative progress” which was so important in his thought and attitudes:
His own generation has the advantage of learning “in a short time the useful things which were found over a long time, with toil and anxiety, by those before us.” If we only proceed rightly [Galen wrote], “nothing stands in the way of our becoming better than those before us.”
Galen sees himself as part of this scientific progress. He has discovered many things in anatomy of which those before him were ignorant, or which they stated badly….
Progress is not limited to the period between the ancients and himself; it includes his own efforts. Thus he has made new discoveries between the first and the second edition of his anatomical work. Altogether, he is restlessly at work to understand what he has not yet fully grasped.
But for Galen what was established by the ancients was no longer open to question. As Temkin writes of his philosophy, “Progress proceeds from principles rooted in ‘the ancients,’ and they have remained valid.” There could be no rejection of what was correctly stated in the beginning by Hippocrates and his school. According to this notion of “cumulative progress,” knowledge must be added to, but not totally reorganized. Galen’s idea of progress excludes the modern notion of the “scientific revolution.” As Ludwig Edelstein has shown, Galen believed in a “unified science,” a “scientia aeterna ruled not by sects but by truth only and receptive to contributions by anybody” (pp. 30-31).
Galen’s system is thus an open one and ready to receive subsequent additions, but it does not allow its foundations to be called in question. It is for this reason that over the centuries Galen could be invoked on the one hand by those who expounded a set of unquestionable “truths” and on the other by those whose experiments were finally to render obsolete the dogmas taken from Galen’s writing.
In its dogmatic version, Galenism is a coherent and simple system which is nevertheless capable of permutations which enable it to explain the most diverse phenomena. He taught that physics was based on four elements (water, fire, air, earth) and the four qualities (hot, cold, dry, moist). This served as a base for the physiology of the four humors and the pneuma; in Temkin’s excellent summary:
Obviously, excess or lack of humors causes disease, as do changes from the normal qualitative makeup of tissues or of organs. Not every deviation is a disease. There is a latitude of health, from the ideal condition to that where the functions are disturbed and where we can definitely speak of disease. Organs can, of course, also be diseased by anatomical changes leading to malfunction, and they may need surgical or mechanical therapy. But in most internal diseases treatment is dietetic or by means of drugs. Foodstuffs and drugs also have their qualitative compositions, so that the deviation of the body or of any of its parts can be changed by offering food, drink, and medicines of the opposite qualities….
He insisted on nine possible types of temperaments, i.e., qualitative mixtures: one, the ideal, in which all qualities were well balanced; four in which one of the qualities, hot, cold, dry or moist predominated; and four others in which the predominating qualities appeared in couples of hot and moist, hot and dry, cold and dry, or cold and moist. The well-balanced mixture served as the frame of reference for all others.
Since the system was capable of proliferation by analogy, many other doctrines came to be added to this basic core. The Middle Ages, partly because of Arab influences, established a rigid and simplified version of Galen’s original thought, at the same time superimposing on it a complicated set of astrological correspondences as well as recent ideas concerning the medicinal qualities of stones, the systematic use of cauteries, and intricate instructions for the correct position and time for bloodletting. However, this meant no fundamental change so long as the perception and interpretation of phenomena remained subject to the same concepts and the same code. The authority of Galen remained intact as long as elementary sense data (which “register” heat, dryness, etc.) were immediately translated into physical entities, which were then used to describe or explain the phenomena in question; the same applies to the relationship between the structure of the organs, as immediately perceived, and their function.
Indeed Galen’s explanatory system with its pairs of opposites, its homologies, and the possible permutations it offers is so closely related to our natural way of perceiving that it seems identical with it. So self-evident does it seem that we do not feel it to be an abstract structure or a replaceable tool; on the contrary, it infiltrates and governs our perceptions, and persuades us that in the very texture of what we feel or see we can have access to the secret inner structure of reality. Galen’s disciples found no difficulty in classifying natural drugs according to their heat, dryness, or moisture. Between the sensations we receive from an object and the concepts we use to interpret it there is only the tiniest of gaps and this is soon closed: a tactile or thermal impression is immediately read as a particular combination of natural elements.