Abstract

The thesis of underdetermination of theory by evidence has led to an opposition between realism and relationism in philosophy of science. Various forms of the thesis are examined, and it is concluded that it is true in at least a weak form that brings realism into doubt. Realists therefore need, among other things, a theory of degrees of confirmation to support rational theory choice. Recent such theories due to Glymour and Friedman are examined, and it is argued that their criterion of "unification" for good theories is better formulated in Bayesian terms. Bayesian confirmation does, however, have consequences that tell against realism. It is concluded that the prospects are dim for scientific realism as usually understood.