In addition to the technical difficulties surrounding the proper formulation of the meaning-criterion, Ayer later acknowledged that he had been vague as to whether the criterion was intended in a ‘weak’ or ‘strong’ sense: if weak, verifiability merely demarcated sense from nonsense, whilst the strong version meant that the method of verification provided the meaning of the sentence. It was the strong version that was used in his discussion of the meaning of sentences about the past and other minds, but in his discussion of the latter another difficulty emerged. It had not been made clear whether the ‘method of verification’ was intended to be neutral between people employing the sentences in question, and so provide a standard meaning for these sentences, or whether such a method could provide an idiosyncratic meaning for one individual’s use of the sentence, the method of verification being peculiar to that person. In his discussion of mental experiences, Ayer had implicitly taken the second route, and so sentences attributing such experiences to himself were given a ‘mentalistic’ analysis, and those attributing experiences to others were given a behaviorist analysis (see the introduction to the second edition of LTL. At the same time, however, he construed another’s self-attribution of experience mentalistically, whereas, as he later acknowledged, to be consistent these should also have been given a behaviorist analysis (see the discussion between Bernard Williams and Ayer in Macdonald 1979).