The Epistemology and Metaphysics of Brain Dysfunction

My project centres on the concept of brain dysfunction as it features in psychiatry, clinical psychology and neuroscience. It can be placed broadly within the emerging field of philosophy of psychiatry, and in a naturalistic tradition.

In scientific psychiatry, the emerging consensus position is that mental disorders can be conceptualised as brain disorders. In the philosophical literature, disorder is hypothesised as being constituted by dysfunction. Understanding the nature of brain dysfunction is thus of crucial importance to contemporary psychiatry and its philosophy. My proposal is premised upon a distinction between two related, but non-synonymous, questions at the heart of any satisfactory account thereof - an epistemological question and a metaphysical question.

The epistemological question asks how brain dysfunction is identified. Can we look at the brain and know for certain that it is functioning incorrectly, or do we need information from a higher explanatory level, for instance the mental or behavioural, to make the relevant discrimination? Our answer here would seem to depend upon what brain dysfunction is. In other words, the epistemological question depends upon the metaphysical question.

I argue that an evolutionary analysis of function - where function is construed as selected effects - implies that mental dysfunction is brain dysfunction. Further, if mental dysfunction is brain dysfunction, mental disorder is brain disorder (constituted by brain dysfunction). This follows from my analysis whether or not mental dysfunctions are identifiable as dysfunctions at lower levels; in other words, regardless of our answer to the epistemological question.