Allusions to Judaism and Christianity.
Galen’s allusions to Judaism and Christianity are of considerable interest. He scarcely seems to have distinguished between them. In two passages in his treatise on differences in the pulse he makes incidental allusion to the followers of Moses and Christ, in both cases speaking of them rather lightly, not to say contemptuously. In criticizing Archigenes for using vague and unintelligible language and not giving a sufficient explanation of the point in question, Galen says that it is “as if one had come to a school of Moses and Christ and had heard undemonstrated laws.”[598] And in criticizing opposing sects for their obstinacy he remarks that it would be easier to win over the followers of Moses and Christ.[599] Later we shall speak more fully of a third passage in De usu partium[600] where Galen criticizes the Mosaic view of the relation of God to nature, representing it as the opposite extreme to the Epicurean doctrine of a purely mechanistic and materialistic universe. This suggests that Galen had read some of the Old Testament, but he might have learned from other sources of the Dead Sea and of salts of Sodom, of which he speaks in yet another context.[601] According to a thirteenth century Arabian biographer of Galen, he spoke more favorably of Christians in a lost commentary upon Plato’s Republic, admiring their morals and admitting their miracles.[602] This last, as we shall see, is unlikely, since Galen believed in a supreme Being who worked only through natural law. “A confection of Ioachos, the martyr or metropolitan,” and “A remedy for headache of the monk Barlama” occur in the third book of the De remediis parabilibus ascribed to Galen, but this third book is greatly interpolated or entirely spurious, citing Galen himself as well as Alexander of Tralles, the sixth century writer, and mentioning the Saracens. Wellmann regards it as composed between the seventh and eleventh centuries of our era.[603]
Galen’s monotheism.
Like most thoughtful men of his time, Galen tended to believe in one supreme deity, but he appears to have derived this conception from Greek rather than Hebraic sources. It was to philosophy and the Greek mysteries that he turned for revelation of the deity, as we shall see. Hopeless criminals were for him those whom neither the Muses nor Socrates could reform.[604] It is Plato, not Christ, whom in another treatise he cites as describing the first and greatest God as ungenerated and good. “And we all naturally love Him, being such as He is from eternity.”[605]
Galen’s Christian readers.
But while Galen’s monotheism cannot be regarded as of Christian or Jewish origin, it is possible that his argument from design and supporting theology by anatomy made him more acceptable to both Mohammedan and Christian readers. At any rate he had Christian readers at Rome at the opening of the third century, when a hostile controversialist complains that some of them even worship Galen.[606] These early Christian enthusiasts for natural science, who also devoted much time to Aristotle and Euclid, were finally excommunicated; but Aristotle, Euclid, and Galen were to return in triumph in medieval learning.
II. His Medicine and Experimental Science
Four elements and four qualities.
Galen held as his fundamental theory of nature the view which was to prevail through the middle ages, that all natural objects upon this globe are composed of four elements, earth, air, fire, and water,[607] and the cognate view, which he says Hippocrates first introduced and Aristotle later demonstrated, that all natural objects are characterized by four qualities, hot, cold, dry, and moist. From the combinations of these four are produced various secondary qualities.[608] Neither hypothesis was as yet universally accepted, however, and Galen felt it incumbent upon him to argue against those who contended that the human body and world of nature were made from but one element.[609] There were others who ridiculed the four quality hypothesis, saying that hot and cold were words for bath-keepers, not for physicians to deal with.[610] Galen explains that philosophers do not regard any particular variety of earth or any other mineral substance as representing the pure element earth, which in the philosophical sense is an extremely cold and dry substance to which adamant and rocks make perhaps the closest approach. But the earths that we see are all compound bodies.[611]
Criticism of atomism.