The range of variation in the items which can fulfill designated functions in a social structure is not unlimited (and this has been repeatedly noted in our foregoing discussion).  The interdependence of the elements of a social structure limits the effective possibilities of change or functional alternatives.  The concept of structural constraint corresponds, in the area of social structure, to Goldenweiser's "principle of limited possibilities" in a broader sphere.  Failure to recognize the relevance of interdependence and attendant structural restraints leads to utopian thought in which it is tacitly assumed that certain elements of a social system can be eliminated without affecting the rest of the system (1968, pp. 106-107).