In any discipline, there will always be a number of underlying philosophical predispositions in the projects of scientists. Some of these predispositions involve the nature of social knowledge itself, the nature of social reality, and the locus of human control in action. Intellectuals have disagreed about the extent to which the social sciences should mimic the methods used in the natural sciences. The founding positivists of the social sciences argued that social phenomena can and should be studied through conventional scientific methods. This position is closely allied with scientism, naturalism and physicalism; the doctrine that all phenomena are ultimately reducible to physical entities and physical laws. Opponents of naturalism, including advocates of the "verstehen" method, contended that there is a need for an interpretive approach to the study of human action, a technique radically different from natural science. The fundamental task for the philosophy of social science has thus been to question the extent to which positivism may be characterized as 'scientific' in relation to fundamental epistemological foundations. These debates also rage "within" contemporary social sciences with regard to subjectivity, objectivity, intersubjectivity and practicality in the conduct of theory and research. Philosophers of social science examine further epistemologies and methodologies, including realism, critical realism, instrumentalism, functionalism, structuralism, interpretivism, phenomenology, and post-structuralism.