現代時空論と不完全決定性の問題

Abstract

Space and Time theories can be regarded as a typical case of "underdetermination of theories by the empirical data." This paper aims to clarify the problem of underdetermination through some concrete examples of space and time theory and to examine two main responses to the problem, namely conventionalism and a priorism. First, underdetermination is defined after the way of van Fraasen. Two theories T and T' are underdetermined if T and T' are empirically equivalent and both empirically adequate. Second, Reichenbach's conventionalism is discussed. According to Reichenbach, when two theories seem to be underdeterminate, they are in fact one identical theory and the difference of them is only in the manner of description of a theory. But we find that this position is based upon a wrong interpretation of scientific theories. Third, a prioristic approach is examined. We understand a priorism as the position that there are some a priori evidences which can select one theory as true among the underdeterminate theories. But we argue that the a prioristic approach will be involved in the infinite regress. We conclude that both conventionalism and a priorism are insufficient to solve the problem of underdetermination.