Conjunctions, Relative Clauses and Noun Clauses
A single sentence can assert more than a single proposition.
The easiest way of combining propositions within a single sentence is to use a conjunction.
Many conjunctions assert a specific relationship between propositions.
Conjunctions like "because," "whenever," and "so that" assert a relationship of dependence.
Conjunctions like "after," "before," "since," "when," "while," and "where" assert a relationship of time or place.
Conjunctions like "but," "although," and "even though" assert a relationship of contrast or seeming opposition.
In all these cases, the conjunction combines component propositions into a statement in which all components are being asserted as true.
Relative Clauses
A clause is a grammatical unit containing a subject and a predicate.
Every sentence, therefore, contains at least one clause, but it may contain more.
A relative clause relates one clause to a particular word in another clause. A relative clause normally begins with a relative pronoun: who or whom, which, or that.
Relative clauses can be either restrictive or nonrestrictive.
A restrictive clause restricts the reference of the term it modifies (a clause).
Example:
The Japanese who eat lots of fish have fewer heart attacks.
The subordinate clause restricts the reference of the term "Japanese" to a certain subclass of the Japanese people: those who eat lots of fish.
As a result, we are making a single statement about that subclass, and we are not making any statement about the Japanese people as a whole.
A nonrestrictive clause doesn't restrict that term's reference.
Example:
The Japanese, who eat lots of fish, have fewer heart attacks.
This proposition asserts that the Japanese have fewer heart attacks and that they eat lots of fish. It makes two statements about the Japanese people as a whole.
Noun Clauses
A phrase that functions as a noun, either in the subject or the predicate of a sentence, is called a noun clause.
Noun clauses can be either asserted or not asserted within a proposition.
Compare these two sentences:
1. The president knows that war is imminent.
2. The president believes that war is imminent.
In both cases we are making an assertion about the president.
In both cases we use a noun clause, "that war is imminent," to convey what it is that the president knows or believes.
And in both cases the noun clause expresses a proposition. The difference is that sentence 1 asserts the proposition, whereas sentence 2 does not.
The English language contains a large class of verbs that we use to describe what people say and think.
We can classify these verbs on the basis of whether or not they imply the endorsement of what is said or thought.
The following verbs do not assert what is said or thought: believes, says, argues, is convinced, and suspects.
The following verbs do assert what is said or thought: knows, acknowledges, proves, is aware, and realizes.
In the study of argument, it is crucial to know whether a speaker is endorsing a given proposition as one of his or her own premises or merely reporting that someone else accepts that proposition.
