My thesis in a nutshell: "There is no convincing reason to assume that explicitly formalized mathematical rules and the clinician's creativity are eq… - Paul E. Meehl

Sir Ronald has befuddled us, mesmerized us, and led us down the primrose path. I believe that the almost universal reliance on merely refuting the null hypothesis as the standard method for corroborating substantive theories in the soft areas is a terrible mistake, is basically unsound, poor scientific strategy, and one of the worst things that ever happened in the history of psychology.

As is well-known (and not disputed by Popper), when we spell out in detail the logical structure of what purports to be an observational test of a theoretical conjecture T, we normally find that we cannot get to an observational statement from T alone. We require further a set of often complex and problematic auxiliaries A, plus the empirical realization of certain conditions describing the experimental particulars C [but] in social science the auxiliaries A and the initial and boundary conditions of the system C are frequently as problematic as the theory T itself.

Because physical theories typically predict numerical values, an improvement in experimental precision reduces the tolerance range and hence increases corroborability. In most psychological research, improved power of a statistical design leads to a prior probability approaching ½ of finding a significant difference in the theoretically predicted direction. Hence the corroboration yielded by "success" is very weak, and becomes weaker with increased precision. "Statistical significance" plays a logical role in psychology precisely the reverse of its role in physics. This problem is worsened by certain unhealthy tendencies prevalent among psychologists, such as a premium placed on experimental "cuteness" and a free reliance upon ad hoc explanations to avoid refutation.