 It is perhaps worth noting that one could have a theory according to which the semantic values of expressions in a sentence are recoverable from the proposition expressed by the sentence, even though the semantic values of the expressions are not (mereological or set theoretic) parts of the proposition. For example, George Bealer [1993] formulates what he calls an algebraic conception of propositions (see also Bealer [1982]). Bealer associates with each proposition a “decomposition tree.” This decomposition tree shows how a given proposition is the result of the application of logical operations to individuals, properties, relations or other propositions (e.g. the application of the logical operation of negation to a proposition P yields a proposition that is true iff P is false; the application of the logical operation of singular predication to an item and a property yields a proposition that is true iff the item possesses the property, etc.). In general, a sentence will express a proposition such that the semantic values of expressions in the sentence will occur on the decomposition tree associated with the proposition. Thus, the semantic values of expressions in a sentence will be recoverable from the proposition (together with its decomposition tree) expressed by the sentence. However, Bealer denies that these semantic values are in any sense set-theoretic members or mereological parts of the proposition. Bealer appears to hold that the proposition is metaphysically simple and has no parts at all. As the term is used here then, Bealer’s is not an account of structured propositions for this reason. We will see below that others hold similar “algebraic” conceptions of propositions, where the propositions are complex entities consisting of constituents bound together in certain ways and so are structured propositions.