Shawn Hood

Within the context of psychological measurement, realist commitments pervade methodology. Further, there are instances where particular scientific practices and decisions are explicable most plausibly against a background assumption of epistemic realism. That psychometrics is a realist enterprise provides a possible toehold for Stephen Jay Gould’s objections to psychometrics in The Mismeasure of Man and Joel Michell’s charges that psychometrics is a “pathological science.” These objections do not withstand scrutiny. There are no fewer than three activities in ongoing psychometric research which presuppose a commitment to a minimal epistemic realism. Those activities include selecting between different models for representing data, estimating ability in the context of item response theory, and the move to make the individual the fundamental unit of analysis in psychometrics thereby calling for a shift in what sorts of data are evidentially relevant. In none of these activities are the commitments and disregard for evidence that Gould and Michell find objectionable or “pathological.”

Scientific realism is, roughly, the thesis according to which science is an epistemically progressive enterprise and current well-confirmed theories are at least approximately true. Putnam has argued that scientific realism is the only philosophy of science that does not make the success of science a miracle. This “explanationist” defense of scientific realism has come under attack by philosophers such as Arthur Fine, Chuang Liu, and Putnam himself. In this paper, I defend the explanationist defense against some of these objections