 Given Disquotation, Lois’s acceptance of (5) and (7) entails that (1) and (2) are true. Now, as deplorable as Lois’s cognitive state is, it seems wrong to convict her of irrationality; she does not seem to believe a contradiction “in the sense in which thoughtful people do not.” (The phrase comes from Perry 1977.) But then it would seem that ‘Clark Kent’ must not be substitutable for ‘Superman’ in (1), else she would. If the substitution of ‘Clark Kent’ for ‘Superman’ in (1) did preserve truth, as it does in (5), then the truth of (1) (and the fact that ‘Clark Kent’ and ‘Superman’ are co-designating) would entail (4). But if both (2) and (4) are true, then, it would appear, Lois believes a proposition and its negation and would thus be guilty of irrationality. As she is intuitively not irrational, ‘Superman’ in (1) is not substitutable salva veritate for ‘Clark Kent’.