 Since the structured proposition expressed by a sentence has a structure similar to that of the sentence and has as constituents semantic values of expressions occurring in the sentence, the theory of structured propositions allows for distinct necessarily equivalent propositions. For example, the propositions expressed by ‘Bachelors are unmarried’ and ‘Brothers are male siblings’ presumably are both necessarily true and hence are necessarily equivalent. But clearly the propositions expressed by these sentences have different constituents and so are distinct. The proposition expressed by the former presumably contains the semantic value of ‘bachelor’ (perhaps, the property of being a bachelor), whereas the proposition expressed by the latter doesn’t. And the proposition expressed by the latter contains the semantic value of ‘brother’, whereas the proposition expressed by the former doesn’t. This is an important virtue of the structured proposition view. The fact that it has this feature and that its main competitor, the possible worlds account of propositions (discussed below), doesn’t is one of the reasons many favor the structured proposition view.