 Jones seems to be perfectly correct here. The Principia argument intending to show that descriptions such as ‘the author of Waverly’ have no meaning in isolation assumes that an expression can only possess one kind of meaning—and thus that sameness of meaning is either sameness of intension or sameness of denotation—and Jones is quite right to challenge this. (But see Perkins 2011 both for an alternative reading of the text as well as a useful history of the debate surrounding its interpretation.) 