A Contractarian Solution to the Experimenter’s Regress

Debiasing procedures are experimental methods aimed at correcting errors arising from the cognitive biases of the experimenter. We will discuss two of these methods, the predesignation rule and randomization, showing to what extent they are open to the experimenter’s regress: there is no meta-rule to prove that, after implementing the procedure, the experimental data are actually free from biases. We claim that, from a contractarian perspective these procedures are nonetheless defensible, since they provide a warrant of the impartiality of the experiment: we only need a proof that the result has not been intentionally manipulated for a prima facie acceptance.