 The claim that the relevant notion of function is in some sense “normative” should also be read with care. What is meant by it is generally just that, when using this notion, we (and biologists) may speak of systems functioning normally or properly, as well as of abnormal functioning, malfunction, dysfunction, functional impairment, and so on. The relevant notion of function is one that permits the possibility of malfunction. That is, it allows for the possibility that a token trait has a function to do Z (in a situation S) while not doing Z (in S), or even while lacking the general disposition to do Z (in  S).[2]  For example, Joe’s pineal gland could have the function to secrete melatonin even if it cannot secrete melatonin because of some internal damage. Whether it is appropriate to describe the notion as genuinely “normative” is unclear, since it is unclear what genuine normativity requires. But all that is usually meant by saying that the relevant notion of function is normative, at least by proponents of teleological theories of mental content, is that the relevant notion permits the possibility of malfunction, and underwrites the central function/dysfunction distinction employed in biology.