I argue that a dilemma arises for naturalistic philosophers of mind in the naturalised semantics tradition. Giving a naturalistic account of the mind is a pressing problem. Brentano’s Thesis — that a state is mental if, and only if, that state has underived representational content — provides an attractive route to naturalising the mental. If true, Brentano’s Thesis means that naturalising representation is sufficient for naturalising the mental. But a naturalist who accepts Brentano’s Thesis thus commits to an eliminativism about the category of the mental. This is because naturalistic theories of representation are reductive, and so over-generalise by applying to patently non-mental states. According to these theories, it has been argued, phenomena like tree rings and saliva come out as representational. Only proposing further Naturalistic conditions on representation could avoid the eliminativist conclusion. But this shows that Naturalists have made only limited progress towards naturalising the mental. And if a Naturalist rejects Brentano’s Thesis, then she gives up on a clear link between representation and mentality. Hence, it is incumbent on the Naturalist to propose another, naturalistically acceptable, mark of the mental. This, again, shows that Naturalists have made only limited progress on the issue of naturalising the mental.