According to Galenic concepts, if diseases are due to alterations of humors either in their quality or in their proportions, then the suitable remedy will restore the appropriate quality or proportion. In Galenic doctrine, the disturbance of the humors should be perceptible, and a sound Galenic remedy should work by perceptibly changing the nature and proportion of the humors back to normal. However, side by side with the Galenic medical doctrines, there were the other prevalent doctrines, among which I can mention the idea of "specifics." I can emphasize three features: the specific remedy was active against a particular disease, in a quite specific fashion, in the same way that an antidote acted against a specific poison; second, the effectiveness was a matter of direct experience, based on empirical observation; and third, the mode of action remained relatively obscure, but nevertheless the medicines did not seem to behave as did the so-called "Galenicals." Thus, whether they acted by "sympathy," or by a special hidden virtue, or by a peculiar microcosmic energy, we cannot say. But the fact remains that many people asserted the specific effectiveness[66] of this or that remedy against a specific disease—e.g., that snakeweed was an effective cure for the bite of a serpent.
Learned physicians, unfortunately, refused in large part to accept the validity of these alleged cures. Their hesitancy rested not on statistical evidence or on niceties of scientific method, but on the grounds that the alleged mode of operation was quite unintelligible and not at all in accord with accepted doctrine.
Boyle, as a chemist, insisted on keeping an open mind in regard to so-called specifics. He objected strongly to the argument that simply because we cannot account for their mode of action, we should conclude that they were not effective. In a passage of great importance, he declared, "Why should we hastily conclude against the efficacy of specificks, taken into the body, upon the bare account of their not operating by any obvious quality, if they be recommended unto us upon their own experience by sober and faithful persons?" Thus, his chain of reasoning is, first of all, these remedies work, as attested by direct experience; we are not able to explain why or how they work; we must not, however, fly in the face of experience and deny their effectiveness simply because of our inability to explain the workings. He gives the example of a "leaven," which in minute amounts is able to "turn the greatest lump of dow [dough] into leaven."[67]
Boyle strongly supported the well-known quotation of Celsus, that the important thing is not what causes the disease but what removes it. In strong terms he criticized "many learned physicians" who rejected specifics on the ground "that they cannot clearly conceive the distinct manner of the specificks working; and think it utterly improbable, that such a medicine, which must pass through digestions in the body, and be whirled about with the mass of blood to all the parts, should, neglecting the rest, shew it self friendly to the brain (for instance) or the kidneys, and fall upon this or that juice or humour rather than any other."[68] Boyle then went into considerable detail to show how this can take place through the action of ferments, combined with a theoretical exposition of atomistic philosophy, which we do not have time to go into at present. He gave in great detail an exposition of how these specifics may operate, but did not in any way produce cogent evidence that they do in fact operate in such fashion.
As a physician, Boyle insisted on facts over theory. He was constantly pleading for physicians to enlarge their experience, to try new medicines, even though these were not based on traditional doctrine. Where observed fact conflicts with theory, the fact cannot be ignored. Credulity of physicians, he indicated, may do the world "more mischief" than any other profession, but nevertheless he condemned those who would try to "circumscribe, or confine the operations of nature, and not so much as allow themselves or others to try, whether it be possible for nature, excited and managed by art, to perform divers things, which they never yet saw done, or work by divers ways, differing from any, which by the common principles, that are taught in the schools, they are able to give a satisfactory account of."[69] Surely, this is not a model of elegant English style, but the message is clear. Boyle was emphasizing the message taught earlier in the century by Francis Bacon, that we must judge the theory by the fact, and not the facts by the theory. It is the same philosophy that Hamlet expounded, that there are more things in heaven and earth than are dreamed of in our philosophy.
We see, thus, that Boyle had taken a mighty step toward modern scientific medicine, but he covered only a small part of the total distance. He insisted that we should accept facts, but he did not realize the difficulties attendant on defining a fact and making it credible. He indicated that when strange results are alleged, "these need good proof to make a wary man believe so strange a thing,"[70] but what constitutes proof was a problem which he was not able to wrestle with and, indeed, a problem which he did not clearly perceive.
I would emphasize that Boyle was in essence a man of great faith. He had great faith in religion, and was a deeply religious man. He was a great supporter of so-called "natural religion" and tried to reconcile the doctrines of natural philosophy with those of traditional religion. Westfall[71] has considered in detail the religious attitudes of late seventeenth-century writers, Robert Boyle in particular. The "proofs" alleged by the proponents of natural religion have, of course, little cogency. As Westfall points out, they examined nature in order to find what they already believed.
Nevertheless, religious faith was only one part of the total faith which Boyle exhibited. He had as much faith in the capabilities, the future progress, and the promise of science as he did in traditional religion. Throughout all his works we see great evidence of his religious piety. But his faith in science, particularly as it affected medicine, we see with utmost clarity in the essay "The Usefulness of Natural Philosophy." He had great vision of the benefits that science would eventually bring to the healing arts. Unlike many of his contemporaries, particularly persons such as Glanvill or Spratt, he realized that many anatomical discoveries, for example, were of little practical value, but he felt that such discoveries would, "in process of time (when the historia facti shall be fully and indisputably made out, and the theories thereby suggested clearly established) highly conduce to the improvement of the therapeutical part of physick...."[72] And with extraordinary perceptiveness he indicated the different ways in which he expected progress to be made through the proper application of mechanical philosophy. He was clear-sighted enough to realize that the discoveries made hitherto were not of great practical value but that the future was indeed bright, and he provided a remarkable blueprint of progress to come.
The measure of progress is, perhaps, the quantity of faith which moves mankind. The study of Robert Boyle emphasizes some divisions among mankind. Some are content to look backward, to be satisfied with the achievements of the past, to rely on accepted systematization, doctrine, and explanation. Others, while dissatisfied with the past, have no guide to lead them anywhere. Still others, however, have a strong faith in the new course which they are pursuing, a faith which can guide them over great difficulties. Boyle was such a man of faith—a word which is really synonymous with "attitude." He marked the transition between the old and the new, and pointed up the difficulties which transition always involves.