Meaning (philosophy)
Other truth theories of meaning<!--'Truth theory of meaning' and 'Truth-theory of meaning' redirect here-->
#### Other truth theories of meaning

The [Vienna Circle](/wiki/Vienna_Circle "Vienna Circle"), a famous group of [logical positivists](/wiki/Logical_positivists "Logical positivists") from the early 20th century (closely allied with Russell and Frege), adopted the [verificationist theory of meaning](/wiki/Verificationism "Verificationism"), a type of **truth theory of meaning**.S. N. Ganguly, *Logical Positivism as a Theory of Meaning*, Allied Publishers, 1967, p. 180\. The verificationist theory of meaning (in at least one of its forms) states that to say that an expression is meaningful is to say that there are some conditions of experience that could exist to show that the expression is true. As noted, Frege and Russell were two proponents of this way of thinking.

A [semantic theory of truth](/wiki/Semantic_theory_of_truth "Semantic theory of truth") was produced by [Alfred Tarski](/wiki/Alfred_Tarski "Alfred Tarski") for [formal semantics](/wiki/Formal_semantics_%28logic%29 "Formal semantics (logic)"). According to Tarski's account, meaning consists of a recursive set of rules that end up yielding an infinite set of sentences, "'p' is true if and only if p", covering the whole language. His innovation produced the notion of [propositional functions](/wiki/Propositional_function "Propositional function") discussed on the section on [universals](/wiki/Universal_%28metaphysics%29 "Universal (metaphysics)") (which he called "sentential functions"), and a [model\-theoretic](/wiki/Model-theoretic "Model-theoretic") approach to semantics (as opposed to a [proof\-theoretic](/wiki/Proof-theoretic "Proof-theoretic") one). Finally, some links were forged to the [correspondence theory of truth](/wiki/Correspondence_theory_of_truth "Correspondence theory of truth") (Tarski, 1944\).

Perhaps the most influential current approach in the contemporary theory of meaning is that sketched by [Donald Davidson](/wiki/Donald_Davidson_%28philosopher%29 "Donald Davidson (philosopher)") in his introduction to the collection of essays *Truth and Meaning* in 1967\. There he argued for the following two theses:
* Any learnable language must be statable in a finite form, even if it is capable of a theoretically infinite number of expressions—as we may assume that natural human languages are, at least in principle. If it could not be stated in a finite way then it could not be learned through a finite, empirical method such as the way humans learn their languages. It follows that it must be possible to give a theoretical semantics for any natural language which could give the meanings of an infinite number of sentences on the basis of a finite system of axioms.
* Giving the meaning of a sentence, he further argued, was equivalent to stating its *truth conditions*. He proposed that it must be possible to account for language as a set of distinct grammatical features together with a lexicon, and for each of them explain its workings in such a way as to generate trivial (obviously correct) statements of the truth conditions of all the (infinitely many) sentences built up from these.

The result is a theory of meaning that rather resembles, by no accident, Tarski's account.

Davidson's account, though brief, constitutes the first systematic presentation of [truth\-conditional semantics](/wiki/Truth-conditional_semantics "Truth-conditional semantics"). He proposed simply translating natural languages into [first\-order predicate calculus](/wiki/First-order_predicate_calculus "First-order predicate calculus") in order to reduce meaning to a function of truth.


What are propositional functions?