Published online by Cambridge University Press: 09 July 2009
This paper argues: (1) that analysis of the issues upon which Popper and Kuhn have been thought to differ – the possibility of conclusive falsification, the incommensurability of theories, and the existence of normal science – reveals no appreciable difference at all; (2) that the basic point of disagreement concerns the role of truth in scientific inquiry, i.e. whether or not truth should be considered the regulative ideal of science; (3) that confusion concerning these issues results from a paradigm shift in epistemology; and (4) that Popper's epistemology proves more attractive than Kuhn's for unification in psychology.
This is a revised version of a paper first presented in colloquium before the Department of Psychiatry at the Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.