This paper helps to clarify the role of empirical evidence in psychological and epistemological theories. Following Galileo's idealization, epistemological theories do not describe the behavior of individuals in the real world. It is only when the "impediments" of the real subjects are gradually removed by experimental manipulation that…

Discusses differences between the epistemic and the psychological subject, the relationship between the epistemic subject and the ideal gas law, the development of general cognitive operations, and the empirical testability of Piaget's epistemic subject. (PR)

Examines the role of empirical evidence in the interpretation of psychological and epistemological aspects of Piagetian theory. Concludes that Galileo's method of idealization has important implications for the construction of a neo-Piagetian epistemological theory. Contains 35 references. (Author/WRM)