Eventually, this could lead to the separation of the various parts of psychology. In some respects, this argument is correct. Psychology definitely has many different approaches or paradigms. It is also true that there is often tension and discontent between these various paradigms. Unlike the so-called 'pure' sciences, there is no one answer to any given psychological problem or issue.
Human phenomena is vastly complex and varied.
Furthermore, people operate not only on a physical level, but also on biological, psychological, and sociological levels. It would be impossible for all these levels of human phenomena to be explained by one single law or principle. For some critics of the discipline of psychology, this may be a bitter pill to swallow. What these critics seem to overlook is the fact that psychology is uniquely positioned to draw information from a vast amount of other disciplines, ranging from philosophy to neuroscience. This dialectical view allows psychologists to look at psychological problems or issues from many different angles.