 Search verbs and desire verbs manifest all three of the behaviors listed in the prologue as “marks” or effects of intensionality. Thus, Lois Lane may be seeking Superman. But it does not seem to follow that she is seeking Clark, even though Superman is Clark, and so we have an example of the first kind of anomaly mentioned in the prologue: substitution of one name with another for the same person leads to a change in truth-value for the embedding sentence (here “Lois is seeking Superman”). Similarly, a thirsty person who believes that water quenches thirst and that H2O is a kind of rat poison may want some water but not some H2O. [According to some, this alleged failure of substitution to preserve truth-value is an illusion; but for reasons of space I do not pursue this theory — its locus classicus is (Salmon 1986).]