Dysfunction as a factual component of disorder

The harmful dysfunction (HD) analysis holds that disorder, mental or physical, requires harm, a value criterion, and dysfunction, a factual criterion referring to failure of a mechanism to perform a naturally selected function. Houts' arguments that the HD analysis does not offer an adequate factual account of dysfunction are examined and shown to be invalid. For example, his claim that the HD analysis confuses function with purpose, a value concept, ignores the analysis'account of function in terms of the value-free notion of effect-explanation; and his argument that functions imply norms (e.g., what mechanisms are 'supposed to' do) falsely assumes that such norms are evaluative. The HD analysis of function is analogous in logical structure to the functional analyst's factual behavioral notion of function. Houts' value account of disorder is inconsistent with people's classificatory judgments, as his own examples demonstrate.