Disease Kinds and Functional Explanations.

Dragulinescu, Stefan (2010) Disease Kinds and Functional Explanations. PhD thesis, UNSPECIFIED.

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Abstract

The present thesis is concerned with the character of kinds in human somatic pathology and the relation that these kinds and their members have with function-based explanations. More precisely, in the first part of the thesis I investigate whether diseased organisms, grouped together on grounds of their shared pathological features, could form natural kinds, taking into account that the paradigmatic natural kinds are the kinds of the exact sciences. The second part of the thesis has as a backdrop the Humean/anti-Humean debate over causation (and the specific construal of explanations according to which to explain is to pinpoint causes). In this backdrop, I enquire into what sort of function-based explanations we could provide for the symptoms and pathological behaviours exhibited by diseased organisms, if we construe such organisms as members of natural kinds. I argue in the first part of the thesis that from a metaphysical point of view, the organisms dealt with in somatic medicine form natural kinds in the same sense in which we take the kinds dealt with in the exact sciences as natural. By comparing a 'classical', exact science kind with a kind of disease, I show that whatever features are associated with natural kind membership (e. g. involvement in laws or inductions, explanatory relevance, possession of 'essential' properties, instantiation of substantive universals, etc. ) there is no 'ontological gap' between disease kinds and the kinds in the exact sciences. The conclusion that diseases are natural kinds has a certain proviso regarding the question of whether the identity of the individual members of natural kinds is dependent upon their kind membership. Should diseases not be natural kinds, the proviso says, it would be because the properties characteristic of natural kinds must have an identity-influence over the kind members. I present in addition serious problems posed by outlining such identity bearing properties. In the second part of the thesis, I argue that function based explanations concerned with diseased organisms - if we construe such organisms as being members of natural kinds - should illuminate positive causes for the symptoms and pathological behaviours they exhibit. We could obtain such function-based explanations, I suggest, if we interpret the functioning of biological items as the manifesting of causal powers. Against the background of the Humean vs. anti-Humean debate on causation, I show that Nancy Cartwright's capacities are a plausible variant for the powers at work in 'pathological' functioning. I argue that one could track down these capacities if one viewed healthy organisms as nomological machines, in the sense in which Cartwright understands this notion. I also suggest that capacities are necessary in order to vindicate general and, more importantly, singular causal claims involved in medical diagnosis and hence to found satisfactory functional explanations.