  As presented so far, the strong interpretation of the medical model includes a demand for understanding biological systems in terms of their normal function if we are to understand why they become abnormal. Kincaid (2008, 375) has argued that a demand like that is unreasonable, because we can conduct research on depression (his example), as we do medical research more generally, based on “partial and unsystematic” causal understanding. Kincaid identifies the demand for a background theory with the search for a “complete wiring diagram of the organism from fertilization to maturity” (377) and he identifies that search with a conception of science as a search for laws of nature and natural kinds. But these seem to be separable: a background theory could comprise a number of partial wiring diagrams arrived at by piecemeal investigation, nor does it have to be driven by a desire for explanation in terms of kinds participating in laws. The questions are, what sort of general orientation toward mental phenomena does the medical model permit, and what sorts of explanations can it encompass? We do not need a complete theory of how biological systems work in order to conduct fruitful research. The issue is whether, at a minimum, there need to be some rough theoretical frameworks and shared empirical claims within which otherwise abnormalities can be identified and outcomes assessed.