Deflationary Theory of Truth - Objections To Deflationism

Objections To Deflationism

One of the main objections to deflationary theories of all flavors was formulated by Jackson, Oppy and Smith in 1994 (following Kirkham 1992). According to the objection, if deflationism is interpreted as a sentential theory (that is, one where truth is predicated of sentences on the left hand side of the biconditionals such as (T) above), then deflationism is false; on the other hand, if it is interpreted as a propositional theory, then it is trivial. Examining another simple instance of the standard equivalence schema:

Grass is green is true if and only if grass is green.

the objection is just that, if the italicized words are taken as a sentence, then it is false, because something more is required for the whole statement to be true than merely the fact that "grass is green" is true. It is also necessary that the sentence "grass is green" means that grass is green and this further linguistic fact is not dealt with in the equivalence schema.

However, if we now assume that grass is green on the left-hand side refers to a proposition, then the theory seems trivial since snow is white is defined as true if and only if snow is white. Note that the triviality involved here is not caused by the concept of truth but by that of proposition. In any case, simply accepting the triviality of the propositional version implies that there can be no explanation of the connection between sentences and the things that they express; i.e. propositions.