UC Berkeley

Abstract

Theories of mental disorders remain scientific in spite of both the absence of reductive explanations and the presence of interventional mental autonomy

by

Katrina Faith Winzeler

Doctor of Philosophy in Philosophy

University of California, Berkeley

Professor John Searle and Professor John Campbell, Co-Chairs

This dissertation asks the question: what is the nature of mental disorders? I explore 3 lines of inquiry that are opened by this question. The first has to do with whether mental disorders can be explained by the natural sciences. I argue that mental disorders are indeed part of the subject matter of the natural sciences, but not because there are reductions between the kinds of abnormal psychology and the kinds of neuroscience. Rather, mental disorders fall under the purview of the natural sciences because 1) they have identifiable, observer-independent causal structures, and 2) their explanations crucially involve the brain. However, these explanations rely on more than just brain anatomy, which is why we need to go beyond the current scientific trend of claiming that mental disorders are just faulty brain circuits. Instead, we should view mental disorders as brain dysfunctions.

The second line of inquiry concerns the grounding of mental disorders as bad things. Where does the normativity come from? Does it require human evaluation or judgment? Since I defend a theory on which mental disorders are brain dysfunctions, I claim that their badness comes from their being mechanisms that have failed to work as they should. The mechanisms at hand have evolutionary histories and therefore their functions should not be understand with regard to their “current causal roles.” I explore Jerome Wakefield’s “Harmful Dysfunction” theory as an example of a dysfunction-based theory of mental disorders, and I take a critical stance towards the notion of ‘function’ that his theory employs. I then outline a new notion of ‘function,’ one that I call a “genetically-open function,” which I believe can avoid the problems raised against the original notion. This new notion of functions links the dysfunctions that are relevant to mental disorders to losses of flexibility and plasticity in response to changing environmental demands. This notion is meant to be suggestive and exploratory.

The third line of inquiry has to do with the causal structures of mental disorders. How do the various etiological factors and symptoms of a type of mental disorder relate to one another? I claim that mental disorders are neither non-natural kinds (like family resemblances or syndromes) nor essentialist natural kinds. Rather, I argue that mental disorders are homeostatic property cluster kinds, collections of symptoms that make one another’s co-occurrence more likely, and whose collective clustering is held in place via some mechanism. This mechanism is

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discoverable a posteriori, so these kinds are observer-independent. Because their causal structures exist out in the world, they are natural kinds, even though they fail to have traditional essences. This naturalness bolsters the argument in favor of mental disorders being proper subject matter for the natural sciences.

Once I explore the nature of mental disorders via these three routes, I investigate the interventions taken to treat them. If mental disorders are brain dysfunctions, and hence can be studied by neuroscience and cognitive science, is there any reason not to think that mental forms of treatment (like psychotherapy) will become obsolete with the improvement of science? I argue that yes, psychotherapy is an ineliminable form of treatment. I claim that recovery does not supervene on the internal state of one’s brain, but rather on that state plus its causal history. The results of psychotherapy are path-dependent and experiential, and cannot be duplicated by a purely medical/physical treatment process. This claim says nothing against materialism and a scientific account of mental disorders. But it does suggest that even in a fully materialist view of mental disorders, there is some autonomy for the mental, at least with regard to interventions.

My overarching goal in this project is thus to demonstrate the false dichotomy between thinking that mental disorders either must fall outside the scope of science entirely, or else must be reduced to fundamental biological entities. We can argue that mental disorders are natural kinds with observer-independent causal structures, and yet still claim that 1) some of that objective causal structure involves contributions from irreducibly mental or environmental variables, and that 2) there are autonomous mental interventions for recovery.