Abstract
Why scientists reach an agreement on new experimental methods when there are
conflicts of interest about the evidence they yield? I argue that debiasing methods play
a crucial role in this consensus, providing a warrant about the impartiality of the
outcome regarding the preferences of different parties involved in the experiment. From
a contractarian perspective, I contend that an epistemic pre-requisite for scientists to
agree on an experimental method is that this latter is neutral regarding their competing
interests. I present two medical experiments (on smallpox inoculation and Mesmerism)
in which debiasing procedures such as blinding and data tabulation provided warrants of
impartiality that made people agree on the experimental design even if they disagreed
on the outcome.