English Semantics

2a Helen put on a sweater.
2b Helen put a sweater on.

These are different English sentences, but they convey the same message—they express the same proposition.

3a Richard wrote the report.
3b Richard is the one who wrote the report.
3c The report was written by Richard.
3d The report is what Richard wrote.

We may say that these four sentences also express a single proposition but they differ in focus: 3b and 3c give a special emphasis to Richard, 3d emphasizes the report, and 3a has no particular focus. In the approach taken here, a proposition does not have a focus; a sentence may add a focus and may add the focus in different places and in different ways. The four sentences about Richard embody the same proposition. A proposition, then, can be realized as several different sentences.

A traditional way of defining a sentence is ‘something that expresses a complete thought.’ This definition is a rather strange way of explaining since it assumes that we know what a complete thought is and with this knowledge can determine whether something is or is not a sentence. But surely the procedure must be the reverse. Sentences are more knowable than thoughts. In spite of individual differences speakers of a language generally agree about what is or is not a sentence in their language. Who can say what a complete thought is? Compare these language expressions:

1a We walk in the park.
1b our walk in the park
1c for us to walk in the park

We call the first a complete sentence, and in writing we begin with a capital letter and end with a period. We say the other two are not complete sentences. But all three expressions have the same semantic content, the same relation to an action or possible action performed in a certain place by two or more people, one of whom is the speaker or writer. The difference is grammatical. The first expression asserts something, makes a statement. The other two expressions can be parts of statements, as for instance:

We enjoyed our walk in the park.
It’s not too late for us to walk in the park.

but they do not make assertions by themselves. The formal differences among these three expressions—we, our and us, for example—are a matter of grammar, not semantics.

The semantic content shared by the three expressions is a proposition. A simple statement like We walk in the park expresses asingle proposition, something presented as a fact and therefore subject to verification; generally speaking, one can find out if the proposition is true or false. We don’t walk in the park is the negation of this proposition, and Do we walk in the park? is a question about it.

Truth-conditional semantics is based on the notion that the core meaning of any sentence (any statement) is its truth conditions. Any speaker of the language knows these conditions. If a sentence is true (or false), what other sentences, expressing partly the same,
partly different conditions, can be judged by this sentence? If a given sentence is true, does this make another sentence also true, or does it falsify the other sentence, or is there no truth relation? Matters of truth and logic are of more importance in truth-conditional semantics than meanings of lexemes per se.
We are not yet finished with the dimensions of meaning. Often we derive more meaning from what we hear or read than what is actually in the message. Perhaps this is due to an intuition we have or to the fact that the speaker or writer infers something—hints at some further meaning. In semantics we are not interested in intuitions or hints but we are interested in the instances when the language of the message implicates some additional meaning that accounts for our inference.

We communicate with utterances, and each utterance is an instance of a sentence. But how can we explain what ‘sentence meaning’ is?
Two points are obvious. First, the meaning of a sentence derives from the meanings of its constituent lexemes and from the grammatical meanings it contains. So if you know all the lexical and grammatical meanings expressed in a sentence, you know the meaning of the sentence, and vice versa. Second, at least if the sentence is a statement, if you know the meaning of the sentence, you know what conditions are necessary in the world for that sentence to be true.

Albert Thompson opened the first flour mill in Waterton.

You don’t know whether this sentence is true or not, but you know that if it is true, there must exist (at some time) a person named Albert Thompson and a place called Waterton (presuppositions), that Albert Thompson opened a flour mill, and that there was no flour mill in Waterton before Albert Thompson opened his mill (entailments). You know that if this sentence is true, the sentence Albert Thompson did not open the first flour mill in Waterton is false (a contradiction).