  The situation is reversed for ‘I’. The content of ‘I’ varies from context to context: its content is Mary in \(c_1\), John in \(c_2\), someone else in \(c_3\), and so on. But given a single context \(c\), the referent of ‘I’ with respect to \(c\) and world \(w\) is the same for any world \(w\) whatsoever. For example, if Mary is the content of ‘I’ with respect to \(c_1\), then Mary is the referent of ‘I’ with respect to \(c_1\) and any world whatsoever. That is why, for any world \(w\), ‘I am a philosopher’ is true at \(c_1\) and \(w\) if and only if Mary is a philosopher in \(w\).