If 'the author of Waverley' meant anything other than 'Scott', 'Scott is the author of Waverley' would be false, which it is not. If 'the author of Waverley' meant 'Scott', 'Scott is the author of Waverley' would be a tautology, which it is not. Therefore, 'the author of Waverley' means neither 'Scott' nor anything else - i.e. ‘the author of Waverley' means nothing, Q.E.D.
Source: My Philosophical Development, chap. 7:1959.
More info.: https://russell-j.com/beginner/BR_MPD_07-150.HTM