Brifely, the central weakness of functionalism after the end of the Second World War became its inordinate emphasis on order and stability. The world had become characterized by conflict and instability and the functionalist view of all things as serving some positive purpose was widely discredited. In addition, functionalism was rooted in a strong positivist tradition, which existentialist thought and, later, post-modernism called out of order. Thus, at both epistemological, ideological and methodological levels, functionalism went into decline and disrepute in the 21st century. Its main strengths are found in the Parsonian school, which incorporated three of the four main theoretical tendencies in sociological theory: i.e. constructionist, systems and utilitarian perspectives. This incorporation of so many elements made it strong and applicable to diverse social situations. Despite Merton's attempts at bringing in "dysfunctions", however, the central weakness of functionalism remains its inability to grapple effectively with the idea and reality of conflict.