 While the four functions of the AGIL scheme are intuitive and many social systems can be described according to the paradigm of Parsons' structural functionalism, one can question the utility that such an inspection brings to a scientific sociological study.Defenders of the AGIL scheme respond that there have indeed been situations where social systems, such as some industries, have failed to operate because they have neglected one or more of the four functions.Hence, the AGIL scheme can be tested against political or economical systems in operation to see if they meet the criteria.