§43. Boyle and the Physicians
Boyle was knowledgeable about the medical theories and discoveries of his age. According to a scholar of his work, “At one time or another he took up most of the topics important to physicians of the day, and provided, by means of his corpuscular hypothesis, interpretations that together form a logical whole for understanding the human body in health and disease.” He had many medical friends, including Harvey and Thomas Sydenham, whom he sometimes accompanied on medical rounds (as did Locke).
He refers repeatedly to patients whom he treated, practitioners who consulted him, or for whom he prepared remedies. His medical research comprised physiological experiments especially on respiration and blood, and clinical experiments with materia medica. He published a Natural History of Human Blood, dedicated to Locke, and a volume of Medicinal Experiments, and was awarded an honorary MD from Oxford University.169He was convinced that medicine and natural philosophy had something important to say to each other, the medical tradition exemplifying the empirical reasoning he wants to bring into experimental natural philosophy. Harvey's admirable demonstration of circulation is an important result proved by an excellent method. The unseen circulation of the blood could only be detected by experiments expressly devised to reveal it. And like Bacon, Boyle expects experimental natural philosophy to be a boon to medicine. He reiterates the medical-rationalist argument that good theories make better doctors. “He, that better knows the nature of the parts and juices of the body, will be better able to conjecture at the events of diseases.” Not only might physicians use theories for the good of their patients, they should look upon their patients as theory teaches them to look on all nature. For Boyle that means a kind of medical mechanism.
“I think the physician... is to look upon his patient’s body, as an engine, that is out of order, but yet is so contrived, that, by his concurrence with the endeavours, or rather tendencies, of the parts of the automaton itself, it may be brought to a better state.”170The medical establishment in Boyle’s day did not encourage experimental medical procedures, including vaccination, which were denounced as dangerous. Boyle thought it was mindlessly prescribed but eminently orthodox bleeding and purging that were the unacknowledged danger to a weakened constitution. He felt strongly enough about the matter that he composed a work attacking orthodox medical practice, only to suppress it due, he said, to the hostility of physicians.171
Boyle follows Galen’s injunction against going too far with empiricism. There is nothing wrong with hypothetical invisible causes provided the experimental evidence is methodically obtained. “There is no necessity... that visibility to a human eye should be necessary to the existence of an atom, or of a corpuscle of air, or of the effluviums of a loadstone.” He criticizes “vulgar philosophers” who, because they are “accustomed to converse with visible objects, and conceive grossly of things,” cannot “imagine any other agents in nature than those that they can see.” For the mechanical philosopher, not all causes are sensible. “Betwixt visible bodies and spiritual beings there is a middle sort of agents, invisible corpuscles; by which a great part of the difficulter phaenomena of nature are produced, and by which may intelligibly be explicated those phaenomena, which it were absurd to refer to the former, and precarious to attribute to the latter.” Experience must be qualified, controlled by reason, that being what medical tradition knew as judgment. “Experience,” Boyle wrote,
is but an assistant to reason, since it doth indeed supply informations to the understanding, but the understanding still remains the judge, and has the power or right to examine and make use of the testimonies that are presented to it.... It is the part of reason, not sense, to judge whether none of the requisites of sense be wanting... [and] it is the part of reason to judge what conclusions may, and what cannot, be safely grounded on the information of the senses and the testimony of experience.172
Boyle rediscovers Galen's method of qualified experience, the Hippocratic synthesis in which experience controls reason and reason controls experience. It sounds impossible in theory, but in practice it proved remarkably effective.