paul_w_ewald's picture
Professor of Biology, Amherst College; Author, Plague Time
Trusting Experts

At the end of The Structure of Scientific Revolutions, Thomas Kuhn suggested that it is reasonable to trust the general consensus of experts instead of a revolutionary idea, even when the revolutionary idea is consistent with a finding that could not be explained by  the general consensus.  He reasoned that the general consensus was reached by drawing together countless bits of evidence, and even though it could not explain everything, it had passed a gauntlet to which the revolutionary idea had not yet been subjected. 

Kuhn's idea seemed sufficiently plausible to lead me to generally trust the consensus of experts in disciplines outside my area of expertise.  I still think that it is wise to trust the experts when their profession has a good understanding of the processes under consideration.   This situation applies to experts on car maintenance, for example, because cars were made by people who shared their knowledge about the function of car parts, and top notch car mechanics learn this information.  It also applies generally to the main principles of mechanical and electrical engineering, biology, physics, and chemistry, because these principles are tested directly or indirectly by the countless studies. 

I am becoming convinced, however, that the opposite view is often true when the expert opinion pertains to the unknown: the longer and more widespread the accepted wisdom has been accepted, the more hesitant we should be to trust it, especially if the experts  have been studying the question intensively during this period of acceptance and contradictory findings or logic have been presented.  The reason is simple.  If an explanation has been widely and broadly accepted and convincing evidence still cannot be mustered, then it is quite reasonable to expect that the experts are barking up the wrong, albeit cherished, trees.  That is, its acceptance has more to do with the limitations of intellectual ingenuity than with evidence. 

This argument provides a clear guideline for allocating trust to experts: distrust expert opinion in accordance with what is not known about the subject.  This guideline is, of course, difficult to apply because one has to first ascertain whether a discipline actually has valid answers for a given area of inquiry.  Consider something as simple as a sprained ankle.  Evolutionary considerations suggest that the inflammation and pain associated with sprained ankles are adaptive responses to promote healing, and that suppressing them would be detrimental to long-term functionality of the joint.   I have searched the literature to find out whether any evidence indicates that treatment of sprained ankles with ice, compression, anti-inflammatories, and analgesics promotes or hinders healing and long-term functionality of the joint. In particular, I have been looking for comparisons of treated individuals with untreated controls.  I have not found any and am coming to the conclusion that this widely advocated expert opinion is a detrimental holdover from ancient Greek medicine, which often confused the return of the body to a more healthy appearance with the return of the body to a state of health.  

More generally, I am coming to the disquieting realization that much of scientific opinion and even more of medical opinion falls into the murky area circumscribed by a lack of adequate knowledge about the processes at hand.  This means that I must invoke broadly the guideline to distrust expert opinion in proportion to the lack of knowledge in the area. Although this has made me more objectionable, it has also been of great value intellectually and practically, as when, for example, I sprain my ankle.