In the long period of domination of philosophical thought, there were some intellectuals who suggested application of empirical method in the study of natural phenomena. However this method found systematic and general application only in the 16th century and proved to be extremely effective in producing new and dependable knowledge about natural entities. In the 19th century, Auguste Comte took long steps in application of this method in the studies of human and social phenomena, and his work was seriously pursued by the intellectuals of Vienna Circle in their endeavor at presenting experimental methodology within the framework of positivism. Positivism was later developed by Carnap and Wittgenstein in two different directions of experimentalism and logical positivism; Logical positivism flourished from the third decade of the 20th century, despite the fact that positivism in either form lacked a logical foundation, because by this method only some parts of a whole is actually studied but the final statement is about the whole itself- the entity which is not actually studied. This point was shown brilliantly by David Hume, but the paradox was that experimental method, despite lack of logical foundation, was amazingly effective.Karl Raimund Popper, in his efforts to solve this paradox, introduced falsification, instead of verification. From this point of view, a researcher must try to disprove a hypothesis. In case of failure he must accept temporarily the hypothesis as true. This means, in effect, metaphysical statements, which are essentially beyond falsification, must be accepted as true and scientific temporarily. Popper was thus the first intellectual in imposing a philosophical view on scientific method in the 20th century and he paved the way of passing from science to metaphysics as well.In the early 1950s Thomas Kuhn in his well-known book, Structure of Scientific Revolution refuted experimentalism in its both versions of verification and refutation, claiming that progress of science has nothing to do with application of experimental method and gradual accumulation of knowledge. Progress of science is achieved through scientific revolutions which substituted a new paradigm for the old one. A paradigm is, in essence, a collection of metaphysical beliefs accepted by the scientific community in a given period of time. This notion was further expanded by Paul Feyerabend who claimed that any noticeable progress in science has been achieved not by following a given scientific method but by breaking methodological taboos. He goes much beyond rejecting experimentalism. He rejects logical positivism as well, by Bidding Farewell to Reason, and prescribing anarchism in knowledge as a whole.To withstand this onslaught, positivism restricted itself as behaviorism applicable in the study of social phenomena. Asa result, a "scientific war" was initiated between behaviorism and methodological anarchism in 1980s which led to critical relativism on the one hand and critical realism on the other. Critical realism, is the dominant methodology of research at present. So one can claim that philosophical and metaphysical efforts to discredit scientific method were notsuccessful.