The methodology of social sciences has always been a matter of much controversy, and it probably will remain so in the foreseeable future. The debate on the method and nature of these sciences is a corollary of their historical development: it began early, as they evolved and rose to prominence. The most important methodological issue in this field was the question of the extent social and physical sciences could be considered similar or different. In philosophy of social sciences a dualistic version maintains that the method of argumentation in these sciences is "natural Reasoning". The location of natural Reasoning is somewhere between the customary persuasion method and law-like verification method. Natural Reasoning depends upon "natural language" more than formalization. It is being said that within such a space, social sciences afford neither falsification nor generalization. Such a claim is perhaps less disputable in political science and anthropology than it is in sociology and economics. Nonetheless, the hard shell of this claim Govers all human and social sciences. This claim amounts to a theory which holds on a fundamental duality of method in human and non-human sciences.The present article seeks exposition and interpretation of such an idea of duality. It looks at its foundations, contents, implications, and presents a cursory criticism of it. Framed within a philosophical analysis and a comparative method, the author will defend the idea that a hardliner dualism is not viable versus a methodological pluralism which does not deny the unity of genus science.