Discussions of determining the boundaries of science -A study on Popper, Kuhn, Lakatos and Feyerabend-

The aim of this assertion is to investigate the existence of new epistemological possibilities in the context of the separation between science and non-science by analyzing the discussions on the demarcation of science in the twentieth century. Focusing on this main purpose, the problem's conceptual framework was given in the introduction of this study. In this context, the terms "science", "non-science" and "pseudo-science" were analyzed and the difficulties encountered in their use were highlighted. The scientific view of the thinkers of the Vienna Circle was discussed at the beginning of the first chapter. The inadequacy of the criterion they developed on the basis of propositional logic and verificationism was mentioned. In the same chapter, Karl Popper's theory of falsificationism was discussed. It has been argued that this theory, as a criterion for demarcation, has similar problems with the positivist criterion. In the second chapter, Thomas Kuhn's approach to paradigmatic science and his defence of 'normal science' as a criterion for demarcation were examined. It was emphasized that, together with the views of T. Kuhn, it became inevitable to evaluate the demarcation problem on a broader basis, which also required the psycho-social context to be taken into account. It was also claimed that Kuhn's efforts for demarcation were inconclusive. In the third chapter, the sophisticated falsificationism of Imre Lakatos was evaluated. It has been argued that his methodology of scientific research programs, which we consider as the Popper-Kuhn synthesis, also rests on the same (method and rationality) constants as Popper's falsificationism, and therefore it fails to offer a solution. In the last chapter, Paul Feyerabend's view of science was given with his critiques on Popper, Kuhn, Lakatos and positivists. It was endorsed that he did not accept the attempts to establish boundaries before him, considered this effort as a futile endeavor, and argued that science should be considered on the basis of values. This section concludes with an assessment of his anthropological approach. In the conclusion section, some general inferences and evaluations regarding the views of the thinkers included in the study were made. Key Words: Science, non-science, pseudo-science, problem of demarcation, scientific method, scientific rationality.