Is there an institutional framework which will promote trustworthy experts? Milton Friedman waged a life-long, futile campaign against the American Medical Association's (AMA) guild-like ability to control licensing of physicians, entry into the profession, as well as standards of medicine:
Licensure has reduced both the quantity and quality of medical practice; that is has reduced the opportunities available to people who would like to be physicians, forcing them to pursue occupations they regard as less attractive; that it has forced the public to pay more for less satisfactory medical service, and that it has retarded technological development both in medicine itself and in the organization of medical practice. (M. Friedman, 1994)
Yet, as Friedman recognized, individuals are unwilling to trust the market to provide "evidence on the quality of a physician." Friedman was unimpressed by claims about the solidity of our medical profession; he believed it revealed "the tyranny of the status quo and the poverty of our imagination in fields in which we are laymen."
Not unlike Locke, Mandeville was a trained and practicing physician. In A Treatise of the Hypochondriack and Hysterick Diseases, in Three Dialogues (1711/1730), Mandeville diagnoses a market failure in medicine: from "self-interest" (then) "young physicians" avoid the "laborious, but tedious way of getting money" that is "spend your ime before the squallid beds of poor patients, and bear with the unsavory smells of a crowded hospital." (39; throughout I am quoting from the 1730 edition.) In doing so physicians fail to build up a stock of diverse and careful empirical practice (unlike the Ancient empiricks). Modern doctors find other ways to obtain a wealthy clientèle by building a reputation among fashionable and rich circles. As I have discussed before one way they can do so is by seeming learned in abstruse sciences (such as mathematics). But Mandeville also recognizes that there are other ways for doctors to get a good clientèle, including sponsoring/producing learned productions, marrying "into a good Family, and your relations will help your into practice, or else cringe and make your court to half a dozen noted apothecaries, promise them to prescibe loads of loads of" prescriptions, "get, but in favor with one that has great business, and yours is done." (40) As he puts it: "Physicians did not begin to reason about Physick [the body], and make Hypotheses, because they thought that what they writ was true, and be of service to thier postericy in curing the sick; but to ingratiate themselves with they ages they lived in." (65) None of these strategies involve curing actual patients.
In the absence of reliable knowledge and in the context of market forces, in Mandeville's day medicine is fashion ridden and prone to constant changes in proposed explanation and treatments. Patients notice the disagreement in "the most essential points" and conclude from their bitter experience with medicine and the lack of consensus in medicine that medicine is a faction-ridden, "deceitful" craft (31) no better than "astrology" (33).
According to Mandeville the preferred solution would be to promote a reform of university research into medicine. Ideally, there would be specialized research professors that focus empirical inquiry on individual diseases with an eye toward treatments. (Mandeville credits Baglivi with this idea.) But Mandeville recognizes that this is a too-costly project, and that as of yet there is no money for this approach. (He does not consider state funding of research.) So, as a sub-optimal substitute, Mandeville urges his fellow physician-practitioners to follow their "conscience" and "supply , as much as he can in his private capacity, the neglect of the publick, and wholly apply himself to the study of one distemper only." (44) Medical practitioners can become specialized experts in their field, and build up a stock of solid empirical knowledge; the exemplary case of which are (besides Ancient empiricks) specialized women nurse-practitioners (72-4). Mandeville also praises women's wisdom in ignoring the treatments of male physicians (73); in context this is quite subversive because it does not merely undermine the claim of male authority over the female body, but also the husband's authority over the wife!
Here I leave aside the superficial surprise that one might feel in recognizing that Mandeville (the notorious author of The Fable of the Bees, "private vices, public benefits"), appeals to private virtue to create public utility. I will just assert that Mandeville thinks that there is in human nature also a good pride that can activate conscience (to argue this I would have to explore his treatment of the Fall). If physicians start caring about their reputation among their peers, they will start the slow process of building up solid, specialist knowledge about the otherwise bewildering evidential complexity of disease. But to do so they must have a mechanism for recognizing the worthy peers, and here Mandeville has nothing to offer.
Of course, the AMA (founded in the nineteenth century) and its peers in other countries, lets experts decide who are the worthy specialist peers and then gets government to enforce this decision. This is said to guarantee a minimal level of medical competence. (This is not the place to investigate Friedman's response.) I believe (but won't argue) that the AMA was founded out of practices that were clearly advocated by Mandeville. Sadly enough, in many countries this development of government enforced professional licensing has meant letting politically better organized men displace the women practitioners praised so highly by Mandeville. Given that Mandeville does not seem to have much faith in providential order, I doubt this sad unintended consequence would have surprised him much.