What makes me who I am? Is it the laws of physics, operating on the cells in my body? Or is it the pressures of society, forcing me into its mould? (Nature or nurture?)
According to Roy Clouser, in The Myth of Religious Neutrality (1, 2, 3, 4, 5, 6, 7, 8), psychology has often tended to choose one or the other of these answers. In terms of Dooyeweerd's aspects (see here), if psychology is the study of the sensory aspect, then psychologists have tended to reduce the sensory aspect either onto the physical and biotic aspects, or onto the social aspect. This often reflects the psychologists' beliefs about the fundamental nature of reality (their religious beliefs). Let's treat each in turn, followed by a different perspective.
1. Psychology reduced to physics and biology. Clouser describes the "behaviourist" approaches of Watson, Thorndike and Skinner, with this summary:
Common to all these theories is the total rejection of allowing into psychology anything about human mental life and experiences that is prima facie non-behavioral such as thoughts, feelings, purposes, and even perceptions (p.166).
Why might these theorists take such an approach?
The reason is their materialist perspective on reality ... that sees all reality as restricted to, or dependent on, the physical aspect. That is, it holds either: (1) there exist only physical bodies and their actions, or (2) any non-physical factors involved are entirely generated by physical bodies and their actions. (p.167).
2. Psychology reduced to sociology. Under this heading would come the theories of Adler and the earlier theories of Fromm (who later moved towards a more pantheistic view of reality).
Adler insisted that psychology is a social science. He held that the goal of psychology "is not to comprehend causal factors, as in physiology, but the direction-giving ... [social] forces and goals that guide all other psychological movements" (p.171).
3. Non-reductionist psychology. The Christian perspective on reality that Clouser presents in his book is one in which God has made creation with its various aspects, and the different aspects cannot be reduced to each other. This view of the whole of creation reflects the biblical view of human nature, in which "each human is ... seen as an essential unity, no matter how many diverse kinds of functions an individual may display in the various aspects of creation" (p.180). Importantly, "this view is at odds with the notion popular among theists that a human is not an essential unity but a duality of two entities—a soul and a body" (p.181). What such a non-reductionist theory might look like in practice will the subject of later chapters.