Boyle, as a clinician, remained on excellent terms with medical practitioners. For one thing, he took great care not to compete with them. As stated,[48] he "was careful to decline the occasions of entrenching upon their profession." Physicians would consult him freely. As a chemist and experimental pharmacologist, he prepared various remedies. Some of these he tried out on patients himself, others he gave to practitioners who might use them. Boyle seems to have abundantly provided what we today call "curbstone consultations."
In no way bound by guild rules and conventions or by rigid educational standards, Boyle was free to learn from whatever sources appealed to him. Repeatedly he emphasized the importance of learning from experience, both his own and that of others, and by "others" he included not only physicians and learned gentlemen, but even the meanest of society, provided they had experience in treating disease. This experience need not be restricted to treatment of humans but should include animals as well. Thus, in speaking of even the "skilfullest physicians," he indicated that many of them "might, without disparagement to their profession, do it an useful piece of service, if they would be pleased to collect and digest all the approved experiments and practices of the farriers, graziers, butchers, and the like, which the ancients did not despise...; and ... which might serve to illustrate the methodus medendi."[49] He was quite critical of physicians who were too conservative even to examine the claims of the nonprofessionals, especially those who were relatively low in the social or intellectual scale. This casts an interesting sidelight on the snobbishness of the medical profession.
Boyle's willingness and ability to ignore the restrictions of an Establishment represent the full flowering of what I might call the Renaissance spirit—the drive to go outside accepted bounds, to explore, to try, to avoid commitment, and to investigate for oneself.
What internal and external factors permit a successful breakaway from tradition? Rebels there have always been, yet successful rebels are relatively infrequent. The late seventeenth century was a period of successful rebellion, and the virtuosi were one of the factors which contributed to the success. Robert Boyle played a significant part in introducing new methods into science and new science into medicine.
We must realize that Boyle was primarily a chemist and not a biologist. He thought in chemical terms, drawing his examples from physics and chemistry; he did not think in terms of the living creature or the organism, and as a mechanist he passed quite lightly over the concept or organismic behavior. His basic anti-Aristotelianism prevented his appreciating the biologically oriented thought of Aristotle. Instead, Boyle talked about the inorganic world, of water, of metals and elements, of physical properties. He ignored that inner drive which Spinoza called the conatus; or the seeds of Paracelsus or van Helmont; or the persistence over a time course of any "essence" or "form." Since he dealt with phenomena relatively simple when compared with living phenomena, he could, for this very reason, make progress, up to a point. As a chemist, he could seek fairly specific and precise correlations of various concrete environmental factors, and then assume that living beings behaved as did the inorganic objects which he investigated. However, he always excepted the soul of man, as outside his investigations.
But while Boyle was a skillful chemist, judged by the standards of his time, we cannot call him a skillful medical investigator. This represents, however, the fault of the era in which he lived rather than any fault peculiar to him. Boyle's medical studies fall into at least two categories. These were the purely physiological experiments, such as those on respiration or on blood, and the more clinical experiments, concerned with pharmaceuticals, clinical pharmacology, and clinical medicine. The purely physiological experiments have great merit and were profoundly influential in shaping modern physiology. The clinical experiments throw great light on the development of critical judgment in medical history, and the relations of judgment and faith.
In 1775, John Hunter wrote a letter to Jenner that has become quite famous. Hunter had just thanked Jenner for an "experiment on the hedgehog." But, continued Hunter, "Why do you ask me a question by way of solving it? I think your solution is just, but why think? Why not try the experiment?"[50] The word "just," of course, in its eighteenth-century sense, means exact or proper, precise or correct. A "just solution" is one that is logically correct. The "think" refers to Hunter's own uncertainty. He is not content with a verbal or logical solution to a problem, he wants empirical demonstration. Why, he is asking, should we be content with merely a logically correct solution when we can have an experiential demonstration. Try the experiment. Put the logical inference to the test of experience.
This empirical attitude, not at all infrequent in the latter eighteenth-century medicine, was quite unusual in the seventeenth-century medicine. This was precisely the attitude that Robert Boyle exhibited in his clinical contacts.
Medicine, at least textbook medicine, was rationalistic. Textbooks started with definitions and assertions regarding the fundamentals of health. This we see particularly in a Galenic writer such as Riverius. Medicine, he said, "stands upon the basis of its own principles, axioms and demonstrations, repeated by the demonstration of nature."[51] In his text, Riverius first expounded a groundwork concerning the elements, temperaments and humors, spirits and innate heat, the faculties and functions; then the nature of the diseases which resulted from disturbances of these; and finally the signs of disease and the treatment that was appropriate. All were beautifully interdigitated in a logical fashion, and for any recommended therapy a good reason could be found. There was, however, a serious difficulty. If anyone were so bold as to ask, But how do you know? only a rather lame answer would come forth. The exposition rested in large part on authority or else largely on reasoning from accepted premises—a "just" reasoning. And while much keen observation was duly recorded and a considerable mass of fact underlay the theoretical superstructure, the idea of empirical proof was not current. Riverius chopped logic vigorously and drew conclusions from unsupported assertions in a way that strikes us as reckless.
For a body of knowledge to be a science, it must indicate a logical connection between first principles, which were "universal," and the particular case. The well-educated physician could always give a logical reason for what he did. The empiric, however, was one who carried out his remedies or procedures without being able to tell why. That is, he could not trace out the logical connection between first principles and the particular case.