Semmelweis Reflex

The Semmelweis reflex is the tendency to reflexively reject new evidence or new knowledge because it contradicts established norms, beliefs or paradigms, without evaluating the evidence on its own merits. The term refers to the Hungarian physician Ignaz Semmelweis, who in the 1840s found that hand-washing with a chlorinated solution dramatically reduced deaths from childbed fever among new mothers, but whose findings were rejected and dismissed by much of the contemporary medical establishment, in part because they contradicted prevailing theories of disease. The phrase is used more broadly, beyond medicine, to describe any situation in which a community of practitioners or experts dismisses new evidence primarily because it conflicts with established practice or belief, rather than because the evidence itself has been shown to be flawed.