Sentence meaning in formal semantics
Because Fauconnier’s Mental Spaces Theory represents a reaction to the truth conditional model of sentence meaning adopted in formal semantics, we begin with a very brief overview of this approach. The truth-conditional model works by establishing ‘truth conditions’ of a sentence: the state of affairs that would have to exist in the world, real or hypothetical, for a given sentence to be true. For example, relative to a situation or ‘state of affairs’ in which the cat stole my breakfast, the sentence The cat stole my breakfast is true, while the sentence The cat did not steal my breakfast is false. The truth-conditional approach is not concerned with empirical truth but rather with establishing a model of meaning based on ‘what the world would have to be like’ for a given sentence to be true. In other words, it is not important to find out whether the cat stole my breakfast or not, nor indeed whether I even have a cat. What is important is the fact that speakers know ‘what the world would have to be like’ for such a sentence to be true. Establishing the truth conditions of a sentence then enables sentences to be compared, and the comparison of their truth conditions gives rise to a model of (some aspect of) their meaning. For example, if the sentence The cat stole my breakfast is true of a given situation, the sentence My breakfast was stolen by the cat is also true of that situation. These sentences stand in a relation of paraphrase. According to the truth-conditional model, they ‘mean the same thing’ (at least in semantic or context-independent terms) because they share the same truth conditions: they can both be true of the same state of affairs. Compare the two sentences we saw earlier: The cat stole my breakfast and The cat did not steal my breakfast. These two sentences stand in a relation of contra diction: they cannot both be true of the same state of affairs. If one is true, the other must be false, and vice versa. These examples illustrate how truth conditions can be used to model meaning relationships between sentences, like para phrase (if A is true B is true, and vice versa) and contradiction (if A is true B is false, and vice versa). This very brief description of the truth-conditional model will be elaborated in Chapter 13. For the time being, we observe that although this model does not rely on empirical truth – you don’t have to witness your cat stealing your breakfast before you can understand that the sentences discussed above stand in the kinds of meaning relationships described – the model nevertheless relies on the objectivist thesis.
The objectivist thesis holds that the ‘job’ of language is to represent an objectively defined external world. In modern truth-conditional approaches, this objective external reality may be mediated by mental representation (external reality as it is construed by the human mind), but in order for a formal truth-conditional model to work, it requires certain objectively defined primitives and values. Furthermore, as we saw in Chapter 7, this kind of approach to linguistic meaning assumes the principle of compositionality: the meaning of a sentence is built up from the meaning of the words in the sentence together with the way in which the words are arranged by the grammar. According to this view, then, the semantic meaning of a sentence is the output of this compositional process and is limited to what can be predicted from the context-independent meanings of individual words and from the properties of the grammar. Any additional meaning, such as the inferences a hearer can draw from the utterance of a particular sentence within a particular context, falls outside the immediate concerns of semantic theory into the domain of pragmatics. From this perspective, semantics is concerned with what words and sentences mean, while pragmatics is concerned with what speakers mean when they use words and sentences in situated language use, and how hearers retrieve this intended meaning. From the formal perspective, these two areas of investigation can be meaningfully separated.
