 There is no question that a major reason for excitement about rigidity is that it underwrites the necessary a posteriori (see also Schwartz 2002, pp. 270ff.). However, in light of the theory of direct reference, this apparent coup may have been overstated or misunderstood. As we observed, direct reference theorists insist that ‘Hesperus = Phosphorus’ and ‘Hesperus = Hesperus’ express the same proposition or share the same content even though these statements have the appearance of saying different things. For direct reference theorists, to say that Hesperus = Phosphorus is to say no more and no less than to say that Hesperus = Hesperus. Since it is a priori that Hesperus = Hesperus, it is a priori that Hesperus = Phosphorus. For this reason, the claim that rigidity presents propositions that are necessarily true and a posteriori might be disputed (Soames 2002, pp. 240, 243; Salmon 1986, pp. 133–42; Fitch 1976; for further discussion, see Fitch 2004, pp. 110–13; Hughes 2004, pp.  84–108).[13]