The epistemic impact of theorizing: generation bias implies evaluation bias

It is often argued that while biases routinely influence thegenerationof scientific theories (in the 'context of discovery'), a subsequentrational evaluationof such theories (in the 'context of justification') will ensure that biases do not affect which theories are ultimately accepted. Against this line of thought, this paper shows that the existence of certain kinds of biases at the generation-stageimpliesthe existence of biases at the evaluation-stage. The key argumentative move is to recognize that a scientist who comes up with a new theory about some phenomena has thereby gained an unusual type of evidence, viz. information about the space of theories that could be true of the phenomena. It follows that if there is bias in the generation of scientific theories in a given domain, then the rational evaluation of theories with reference to the total evidence in that domain will also be biased.