Many philosophers of science have questioned the claim that science is - or should be - "value free". However, most discussions of Evidence Based Medicine (EBM) have focused on its distinctively epistemological claims; for example, concerning the superiority of RCTs to mechanistic evidence. This paper draws on claims that science is value-laden to identify a distinctively ethical - rather than epistemic - criticism of EBM: it is based on a moral mistake.

Specifically, I do three things. First, I sketch a distinctive account of what it means for a scientific movement to be "based on" a moral theory or principle at all. Second, I argue that we can interpret EBM as based on a moral principle: primum non nocere, or "first, do no harm". Third, I argue that this moral principle is mistaken: while non-maleficence is an important moral consideration, it is not the primary moral consideration. Dropping the "first" from "first, do no harm" provides a surprising motivation for a form of evidential pluralism.