A common view about Moore’s Proof of an External World is that the argument fails because anyone who had doubts about its conclusion could not use the argument to rationally overcome those doubts. I agree that Moore’s Proof is—in that sense—dialectically ineffective at convincing an opponent or a doubter, but I defend that the argument (even when individuated taking into consideration the purpose of Moore’s arguing and, consequently, the preferred addressee of the Proof) does not fail. The key to my (...) defence is to conceive the Proof as addressed to subjects with a different epistemic condition. To sustain this view I formulate some hypothesis about the common general purpose of arguing and I defend that it can be fulfilled even when the addressee of an argument is not someone who disbelieves or doubts its conclusion. (shrink)