Moore ’ s Proof and Martin Davies ’ s epistemic projects

In the recent literature on Moore’s Proof of an external world, it has emerged that different diagnoses of the argument’s failure are prima facie defensible. As a result, there is a sense that the appropriateness of the different verdicts on it may depend on variation in the kinds of context in which the argument is taken to be a move, with different characteristic aims. In this spirit Martin Davies has recently explored the use of the argument within two different epistemic projects called respectively ‘deciding what to believe’ and ‘settling the question’. Depending on which project is in hand, according to Davies, the diagnosis of its failure—if indeed it fails—will differ. I believe that, by introducing the idea that the effectiveness of a valid argument may be epistemic project-relative, Davies has pointed the way to an important reorientation of the debates about Moore’s Proof. But I wish to take issue with much of the detail of his proposals. I argue that Davies’s characterisation of his two projects is misleading (§1), and his account of their distinction defective (§2). I then canvass some suggestions about how it may be improved upon and about how further relevant kinds of epistemic projects in which Moore’s argument may be taken to be a move can be characterised, bringing out how each of these projects impinges differently on the issue of the Proof’s failure and of its diagnosis (§§3 and 4). In conclusion (§5) I offer a summary of the resulting terrain. Here’s an argument, which, on the face of it, is perfectly in order: (I) Here’s a hand; (II) If there is a hand here, there is an external world; (III) There is an external world After all, it is just an instance of modus ponens and the premises, given only a very ordinary and commonplace set of circumstances, are surely unexceptionable. Still, the argument remains