Unity and diversity in psychiatry: some philosophical issues.
OBJECTIVE: The aim of this paper is to provide a defence of diversity in psychiatry and, correspondingly, to show that strict 'biologism' (or any other 'total' approach to psychiatry) is inappropriate. METHOD: Arguments are developed using as a basis the writings of well known philosophers such as Stephen Toulmin, Joel Feinberg and Charles Taylor. The authors examine the concepts of explanation and causation and consider the consequences for psychiatry which might follow the acceptance of mind-brain identity. There is also a discussion of the concept of a person. RESULT: If the same phenomenon is subject to explanation from diverse psychiatric perspectives, it does not follow that these modes of explanation must exclude or be in competition with each other. They may in fact be necessary to each other if psychiatry is to provide a full picture of mental functioning and human conduct. The thesis of mind-brain identity does not eliminate the variety of discourses within psychiatry, and hence it does not provide a rationale for 'biologism'. CONCLUSION: There is a need for a co-operative multidimensional approach in psychiatry.