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 …