The ontological structure of the truth-maker of a true sentence cannot be read off from the syntactic structure of the sentence of which it is the truth-maker.
Oppy is not denying that many predicates express properties; he is denying that all do. Taking a page from David Armstrong (1978), he is saying that predicates and their senses provide no sure guidance as to what properties (Armstrongian immanent universals) the world contains. It follows that the ontological structure of the truth-maker of a true sentence cannot be read off from the syntactic structure of the sentence of which it is the truth-maker. Therefore, the fact that our two sentences (3) and (4) have the form a is F does not warrant the conclusion that the respective truth-makers have...