Sentence Meaning (04-Mar-2004)

There's more to learning a language than learning the meaning of all the individual words. Words can be combined into sentences, and sentences have meaning depending on the way that the words have been combined. E.g. "John kills Bill" has the same words as "Bill kills John" but the meaning is different.

As words have antonyms, so sentences can be negated, not necessarily by using antonyms. E.g. the proposition "Mary likes books" can be negated by saying either "Mary doesn't like books" or "Mary dislikes books". As words have synonyms, sentences can have paraphrases. E.g. "Mary went to the seaside on the train" could be paraphrased "Mary took a train to the seaside".

Words can change their meaning depending on the context of the sentence. For example, the temperature represented by the word cold is probably different in the sentences "a cold day in August" and "the ice-cream was cold".

Sentences can be declarative, meaning that they express a propostion (something which can be asserted, denied, or questioned). Such sentences have a true/false value, which is not possible for words and phrases (e.g. "red", "over there").

Sense and Reference

A proposition such as "The king of France is bald" has no truth value, since it has no reference (there's no such thing as the king of France). But it does have sense, because we know what it would be talking about if such a thing existed. If the king of France were to exist, he would be the referent of this proposition.

In the proposition "The venue for the Olympic games", the reference will be different every four years, although the sense is always the same.

Phrases can have sense and reference, and it's possible for two phrases to have a common reference but different sense, e.g. "my uncle" and "my father's brother" both have the same reference but arguably a different sense.

Entailment

Entailment relies on knowledge of the meanings of words and sentences: the sentence "He ate shepherd's pie again" entails:

Entailment occurs when the truth of one proposition necessarily implies the truth of another. E.g. "I don't watch soaps" entails "I don't watch EastEnders". A test for whether one proposition entails another is to see whether negating the second makes the first non-sensical. For example:

  1. I don't eat meat
  2. I don't eat bacon
A entails B, because negating B (saying "I eat bacon") makes nonsense of the claim that "I don't eat meat".

Presupposition

Presupposition refers to an assumption which is implicit in a proposition. For example, "I will go to France again" presupposes that a previous visit has been made to France. A test to see whether one proposition presupposes another is whether, it is possible to negate the first without making the second be non-sensical (this is called constancy under negation). For example:
  1. I will go to France again
  2. I have been to France before
It is possible to negate A, and say "I won't go to France again", without invalidating B.

Note that presupposition and entailment may both be true (as in the above case: the fact that I will go to France again entails a previous visit).

Implicature

Implicature is "anything that is inferred from an utterance but that is not a condition for the truth of the utterance" (see SIL glossary). Sounds a bit like a weak version of presupposition to me.

Useful book readings for this lecture:

Sounds, Grammar and Meaning page