To resume sharing some notes I scribbled down on the contributions to our Philosophy of Science Association symposium on Philosophy of Statistics (Nov. 4, 2016), I’m up to Gelman. Comments on Gigerenzer and Glymour are here and here. Gelman didn’t use slides but gave a very thoughtful, extemporaneous presentation on his conception of “falsificationist Bayesianism”, its relation to current foundational issues, as well as to error statistical testing. My comments follow his abstract.
Confirmationist and Falsificationist Paradigms in Statistical Practice
There is a divide in statistics between classical frequentist and Bayesian methods. Classical hypothesis testing is generally taken to follow a falsificationist, Popperian philosophy in which research hypotheses are put to the test and rejected when data do not accord with predictions. Bayesian inference is generally taken to follow a confirmationist philosophy in which data are used to update the probabilities of different hypotheses. We disagree with this conventional Bayesian-frequentist contrast: We argue that classical null hypothesis significance testing is actually used in a confirmationist sense and in fact does not do what it purports to do; and we argue that Bayesian inference cannot in general supply reasonable probabilities of models being true. The standard research paradigm in social psychology (and elsewhere) seems to be that the researcher has a favorite hypothesis A. But, rather than trying to set up hypothesis A for falsification, the researcher picks a null hypothesis B to falsify, which is then taken as evidence in favor of A. Research projects are framed as quests for confirmation of a theory, and once confirmation is achieved, there is a tendency to declare victory and not think too hard about issues of reliability and validity of measurements. Continue reading