Gottlob Frege was probably the first philosopher or logician to note that predicating truth or existence does not express anything above and beyond the statement to which it is attributed.
Ramsey recognized that the simple elimination of the truth-predicate from all statements in which it is used in ordinary language was not the way to go about attempting to construct a comprehensive theory of truth.
This can be easily translated into the formal sentence with variables ranging over propositions For all P, if John says P, then P is true.
But attempting to directly eliminate "is true" from this sentence, on the standard first-order interpretation of quantification in terms of objects, would result in the ungrammatical formulation For all P, if John says P, then P. It is ungrammatical because P must, in that case, be replaced by the name of an object and not a proposition.
Ramsey attributed this to a defect in natural language, suggesting that such pro-sentences as "that" and "what" were being treated as if they were pronouns.
This "gives rise to artificial problems as to the nature of truth, which disappear at once when they are expressed in logical symbolism..." According to Ramsey, it is only because natural languages lack, what he called, pro-sentences (expressions that stand in relation to sentences as pronouns stand to nouns) that the truth predicate cannot be defined away in all contexts.
There are sentences...in which the word "truth" seems to stand for something real; and this leads the speculative philosopher to enquire what this "something" is.
Like Ramsey, Strawson believed that there was no separate problem of truth apart from determining the semantic contents (or facts of the world) which give the words and sentences of language the meanings that they have.
Tarski's material adequacy condition, or Convention T, is: a definition of truth for an object language implies all instances of the sentential form where S is replaced by a name of a sentence (in the object language) and P is replaced by a translation of that sentence in the metalanguage.
So, for example, "La neve è bianca is true if and only if snow is white" is a sentence which conforms to Convention T; the object language is Italian and the metalanguage is English.
In the case of "John believes everything that Mary says", if we try to capture the content of John's beliefs, we would need to form an infinite conjunction such as the following: The disquotation schema (DS), allows us to reformulate this as: Since x is equivalent to "x" is true, for the disquotationalist, then the above infinite conjunctions are also equivalent.
Grover, Camp and Belnap developed a deflationary theory of truth called prosententialism, which has since been defended by Robert Brandom.
Another way of formulating the minimalist thesis is to assert that the conjunction of all of the instances of the following schema: provides an implicit definition of the property of truth.
One of the main objections to deflationary theories of all flavors was formulated by Jackson, Oppy and Smith in 1994 (following Kirkham 1992).
Michael Dummett, among others, has argued that deflationism cannot account for the fact that truth should be a normative goal of assertion.