Abstract: This paper discussed the unity and disunity of Western psychology. It was argued that the crisis of fragmentation in psychology was an irrefutable fact in that (a) there was not any common ground or a common starting point in psychology hitherto, and (b) different branches of psychology were threatening to break up the discipline of psychology. Psychology could be, however, a unified discipline because the conflicting components in psychology were compatible and commensurable. In approaching towards a unified discipline, there were two major obstacles: objectivism and relativism. Objectivism in psychology was a kind of totalitarianism because it tried to mimic the natural science model and led all psychologists to focus exclusively on objective methods. Objectivism repressed the voice of others and would be harmful to real unification in psychology. While objectivism was characterized as totalitarianism, relativism was more like egalitarianism. Under the guiding principle of "everything goes", relativism in psychology argued that diversified theories, conflicting ideas and competing communities should be considered as equal because they were all valid relative to the context and the culture from which they emerged. But the truth was that relativism encouraged diversity and pluralism without setting up any common ground and hence resulted in an exacerbation of the fragmentation of psychology. It was suggested that the unification of psychology should allow diversified theories, ideas, opinions and methods to coexist, provided that they were founded on a common ground. Psychology, in the author's opinion, should take systems theory as its guideline in order to be a unified discipline.

Key words: fragmentation, unification, objectivism, relativism, psychology