It is especially with regard to the attitude of the churchmen, the people, and even the physicians of the Middle Ages toward insanity, that most opprobrium has been heaped upon the Church and her teachings in the so-called histories of the relations of science to theology or faith. Much of what has been said that has been supposed to tell worst against the Church, however, should not rest upon the shoulders of ecclesiastics, and should not be set down to the evil effect of theology. It is easy now to look back and blame men for the acceptance of supernatural agencies as causes in nearly all cases of mental and nervous diseases, but the reason for this is rather to be looked for in the nature of man than in his belief in religion. Ethnology shows us traces of it everywhere. Our American Indians, long before any tincture of Christianity, and before any hint of theology of any kind reached them, beyond that which develops spontaneously from the depths of their natural faculties, believed in the effect of the evil spirits in producing disease, and, of course, particularly the mental diseases which made men do things so contrary to their own interests, and often so harmful to the beings they loved best in the world.
In the Middle Ages they had not yet outgrown this primitive way of looking at mental diseases. For that matter, we have not even as yet. The intelligent classes in the community are, as a rule, convinced of the physical basis of mental diseases, but there are a great many people who still are inclined to think that some of them, at least, are manifestations of some punitive force outside of the patients themselves, or even some manifestation of ill-understood forces quite apart from matter. Not all the thinking people of the Middle Ages accepted all the absurd notions sometimes rehearsed in this matter, but as in our own time, foolish traditions and superstitions dominated the unthinking classes, which form still, unfortunately, the great mass of mankind. We have had just the opposite delusions forced upon our attention in our own day. Large numbers, supposedly of intelligent people, have pretended to believe or have definitely accepted the teaching that disease is nothing. This is quite as foolish as attributing to spiritual agencies what has come to be recognized as due to physical factors. It is to be hoped that our generation and its thinking shall not be judged by future generations to have been utterly foolish, just because a few millions of us accepted Eddyism,–and it must be remembered that these are not, as a rule, the uneducated.
James J. Walsh, The Popes and Science (1908)