 One important aspect of mental representations that a theory of mental content needs to account for is their so-called “normative” nature. We may evaluate beliefs as true or false, memories as accurate or inaccurate, perceptions as veridical or illusory, desires as satisfied or not satisfied, and motor instructions as correctly or incorrectly executed. The mental states we evaluate in these ways count as true or false, accurate or inaccurate (etc.) by virtue of their contents, as well as by virtue of other things (such as the actual state of the world). For example, the truth of a belief that today is sunny depends on whether it is sunny, but also on it being a belief that today is sunny. If the content of the belief were different (e.g., if it were a belief that today is hot) then its truth value might be different. The “normative” nature of mental content poses at least a prima facie problem for all naturalistic theories of it, given the Humean warning against trying to derive prescriptive from descriptive facts. Teleological theories share the strategy of explaining the norms pertaining to mental content as deriving from so-called functional “norms”, which are regarded as descriptive rather than prescriptive. We return to this in the next section.