The Dogmatists and Wright on Moore's "Proof"

Suppose one has a visual experience as of having hands, and then reasons as follows: (MOORE) (1) I have hands, (2) If I have hands an external world exists; (3) An external world exists. Suppose one's visual experience gives one defeasible perceptual warrant, or justification, to believe (1) - that is, one's experience makes it epistemically appropriate to believe (1). And suppose one comes to believe (1) on the basis of this visual experience. The conditional premise (2) is knowable a priori. And (3) can be established by modus ponens inference. If one reasons thus, say one's engaged in ( MOORE)-reasoning. What, if anything, is wrong with (MOORE)- reasoning? I consider two prominent responses to this question - the dogmatists' and Crispin Wright's. Each finds fault in (MOORE)-reasoning, but on different grounds. I argue Wright's response faces a problem which is standardly only taken to be faced by dogmatists.