The hypothesis of rationality in Neo-classical Economics tells us that the individual has consistent preferences. The cornerstone of this approach is the idea of choice consistency. Even though it is a useful idea for explaining some aspects of economic agents' behavior and is also an interesting tool for making economic rationality approach models, it is restricted and poses its own problems when policy-makers use it with the neo-classical approach findings.
This approach is discussed and other possibilities for studying rationality in economics are showed. For this purpose, three steps have been identified in this paper. First, the most important elements in the neo-classical proposal are discussed.