 If a norm of reaction has this shape, we can say that P is ‘genetically determined’ even though it has an environmental factor as one of its causes. Philip Kitcher suggests that some norms of reaction may have this form, but only in some limited, but perhaps contextually important, range of environments (Kitcher 2001). For example, a disease caused by the loss of one or both normal copies of a gene might develop in every environment except those specifically structured as clinical interventions to cure the disease.