Three types of criticism are currently raised against the acceptance of the rationality principle in economic science. The first relates to the circularity of the reasoning, the second concerns the protection of the theory against refutation, and the third - the most relevant - concerns the empirical inadequacy of the concept. This article aims to discuss the last criticism, considering the work performed by Popper, in different moments of his career, devoted to determine the epistemological status of the rationality principle. There are three main possible answers to be examined below. The first suggests that this postulate be considered as a general law of human behavior. The second requires it to function as an axiom of the theory. Finally, the answer to the third criticism sees the rationality postulate as a methodological rule. The article is finished with a statement that the last solution is a good answer to the core of the above referred criticisms to the conventional concept of rationality. Therefore it is concluded that, as far as it is situated in a metatheoretical context, the rationality postulate embraces undeniable importance as a foundation of economic theory. Its absence or non-existence would imply the unavailability of instruments leading to the very selection of the empirical data designed to submit the theory to tests.
epistemology of the economic science; Karl Popper; postulate of rationality
