The role of empirical evidence is generally considered to be crucial for accepting or rejecting a theory in both the natural sciences and psychology, which has led to the formulation of the quantitative imperative. It is argued that despite the dominance and popularity of the quantitative imperative, the history of science shows that scientific progress has frequently involved a confrontation between the quantitative imperative and the imperative of presuppositions. In order to formulate his law of gravitation, Newton inevitably resorted to idealization based on a hypothesis, that is, a transaction between the quantitative data and the imperative of presuppositions. Similarly, in psychology, both Piaget and Pascual-Leone invoked Galilean-style idealizations in order to develop their research programs. It is concluded that if research in psychology had been entirely under the influence of the quantitative imperative, both Piaget and Pascual-Leone's theories would have long been falsified and forgotten.
