  One might think that the medical model merely commits us to a brain-based view of mental illness with few implications for science, and it is true that clinical or scientific differences across practitioners seldom seem to have much to do with divergent interpretations of the medical model. However, many theorists have argued that our current diagnostic categories, as compiled into DSM-5 (American Psychiatric Association 2013: I refer to different editions of this work by its abbreviated title), are faulty because they are derived from observable phenomena rather than underlying physical pathologies. These theorists are sceptical about many existing psychiatric diagnoses, and not just on empirical grounds; they see DSM diagnoses as collections of symptoms rather seeing them as medicine understands diseases—in terms of destructive processes realized in bodily tissues. Genuine mental illnesses, on this view, are not just sets of co-occurring symptoms but destructive processes taking place in biological systems. Following Murphy (2009), this may be termed the strong interpretation of the medical model. In contrast, a minimal interpretation of the medical model thinks of mental disorders as collections of symptoms that occur together and unfold in characteristic ways, but it makes no commitments about the underlying causes of mental illness.