Tuesday, 28.09.2021

Jon Jureidini and Leemon MacHenry: The Illusion of Evidence Based Medicine: Exposing the Crisis of Credibility in Clinical Research


Leemon McHenry’s reply to David Healy and Hector Warnes’ comments


       We thank Drs. David Healy and Hector Warnes for their insightful comments on our new book, The Illusion of Evidence Based Medicine.  We are especially pleased to see mention of Karl Popper’s philosophy of science.  Dr. Healy is correct that we appeal to Popper as a guide through the epistemic morass of the pharmaceutical industry’s manipulation of research.  It was Popper’s emphasis on rigorous testing that seemed to us the best approach to exposing how poorly industry-sponsored studies measure up to scientific status.    

       To be clear, Popper argued that science does not confirm hypotheses but only disconfirms them in what he called “falsification.”  This is born out in the logical asymmetry between confirmation and falsification We pursue truth but at best we only have the expectation of finding out where our theories are mistaken and replacing them with better ones ―“better ones” here means ones that have not been proved false yet. A positive result in an experiment will never prove the hypothesis; it simply does not disprove it.  But a negative result in an experiment is a decisive refutation.  Popper replaced confirmation with corroboration. A theory is corroborated if it has withstood genuine attempts at falsification, but it is never anything more than a working hypothesis.

       We recognize, however, that in medicine the issue is reliability. The science of medicine requires life and death decisions based on the likelihood that a treatment will work.  What is required in the science of medicine differs from physics, chemistry and biology in that the reliability of a theory is crucial for treatment in clinical practice.  In this regard, other principles of medicine or clinical research will be needed to address this limitation in Popper’s model, i.e., statistical significance, confidence intervals, effect sizes, clinical meaningfulness and the like.  The fact that medical research is probabilistic, however, cannot be an excuse to dismiss those aspects of Popper’s approach that apply just as much to medicine as any other science.   This speaks to Dr. Warnes’ comment that “medicine is not an exact science.”

       The pharmaceutical industry produces pseudoscience for its ad hoc manipulations of data and its failure to take falsification seriously.  When Popper wrote his great works, The Logic of Scientific Discovery (1934) and The Open Society and its Enemies (1945), he saw that political motives were a threat to preserving the integrity of science but there are also hints in his work that he saw the potential of the profit motive of industry to corrupt science.  He writes: “My own misgivings concerning scientific advance and stagnation arise mainly from the changed spirit of science, and from the unchecked growth of Big Science, which endangers great science” (Popper 1994).



Popper, K.  The Logic of Scientific Discovery, New York: Basic Books; 1934.

Popper, K. The Open Society and its Enemies, 2 vols. London: Routledge; 1945.

Popper, K. The Myth of the Framework: In Defence of Science and Rationality, London: Routledge; 1994. 


April 15, 2021