In a series of papers, Papineau argues that the Swampman scenario is not even the start of an objection to teleosemantics as a scientific reduction of belief. It is against this claim that I want to argue here. I shall argue that our intuition about the scenario questions the adequacy of the conceptual foundations of teleosemantics, namely, success semantics and the etiological conception of biological function, on which the explanatory power of the theory rests. In the course of argument, some general connections between explanation and modality will be developed that shed a new light on Kripke's analysis of necessary a posteriori propositions. The upshot will be that teleosemanticists should tackle the Swampman objection head-on.