The philosophy of social science was described as meta-theory which is base assumption of all theories.Before we can understand the theory. We should understand the basic vocabulary Philosophy of the Social Sciences to establish conformity. These terms have the effect of creating new theories in the social sciences, which include Epistemology (Theory of knowledge) Methodology (Theory of methods) and Ontology (Theory of being) are in position to build on the theoretical assumption. Asking questions and looking at the world differently. There are two questions to debates. First, Is IR science or art. Second, what is definition of science and art. And you need to know period of positivism because it is base experiment before becoming IR theory. Social science debates within the discipline can be moved forward by a comprehensive re-examination of what science is. So reviewing the historical and contemporary philosophy of social science debates in IR, the chapter also points towards new accounts of science that have been introduced to the discipline in the last decade. Science, we argue is not based on a dogmatic insistence on the certainty of its claims but, rather, rests on a commitment to constant critique.