 However Moore did not invent this argument. A.N. Prior, in his Logic and the Basis of Ethics (1949: ch. IX), traces it back to Cudworth in the 17th Century, though it doubtful whether Moore was aware of this. (He does not seem to have been particularly well read.) But it certainly occurs in Sidgwick, which is presumably where Moore got it from. The Barren Tautology Argument is to be distinguished from the Open Question Argument proper (the OQA), which Moore did invent, at least in its modern form. This occurs at PE: §13, a section that does not appear in the 1898 draft. It can be stated thus: