Function.—The substantive clause is one that performs some office of a noun. It is not a mere substitute for a noun, however, used for the sake of variety. On the contrary, it is seldom possible to change a noun clause to a noun, and just because there is no equivalent noun in the language. In the sentence,—“I fear that he will come,” it would appear at first thought that the noun clause, that he will come, might be changed to his coming, but this would change the meaning; for the clause implies that his coming is not expected with any certainty, while the expression his coming implies that it is so expected. Every time, in fact, that a noun clause is used, it serves a distinct purpose, and it is safe to assume that in a well-constructed sentence no other element would answer so well. Let us discover some of these purposes.
In the following sentence from Burroughs,—“To what extent the birds or animals can foretell the weather is uncertain,” we have predicated something not of a person, place, or thing, that could be named by a noun, but of a thought, the statement of that thought telling us of an agent and an activity performed by that agent. Hence, by means of the noun clause we can make predications of thoughts instead of things.
In the sentences,—
“Now one codicil in my general law of freedom had been that my seventeenth birthday should not find me at school”; and, “The consequence is, that the seven, or nine, or fourteen lines have a marvellous aptitude at knotting themselves up beyond the reach of skill and patience,”—we are enabled by means of noun clauses to tell what the codicil and the consequences are. We might give a general definition of such nouns by means of other nouns, but to tell what this special codicil and what this special consequence are there is no other way than by the use of the noun clause. Hence, by means of the noun clause, we can make certain predications that could be made in no other way.
In the sentence,—
“Whatever ornaments she wears are of massive gold,”—we have made a predication of certain ornaments; but instead of enumerating them in a long list we have designated them by means of a noun clause, brief but more comprehensive than any list could be. Hence, a noun clause may be used to designate things when we have no names for them, or wish to withhold the names, or find it awkward to use them.
Uses of the Substantive Clause.—As a sentence-element it has most of the important uses of the noun.
1. Subject of a verb,—“What is true of individual men is true also of races.”—Lowell. Frequently, for the sake of a more pleasing arrangement, the anticipative subject it is used, and the real subject, a noun clause, is placed after the predicate,—“It matters little what virtues a man has, if he is habitually inexact.”
A common type of sentence, similar to this, is one in which the anticipative subject is followed by the verb is, next by an adverb, or a phrase, or a clause, and then by the real subject; for example, “It is chiefly through books that we enjoy intercourse with superior minds.” If we say, “It is chiefly through books,” the question at once arises, “What is chiefly through books?” The answer is, “the fact that we enjoy intercourse with superior minds.” Transposing the sentence, we have,—“That we enjoy intercourse with superior minds is chiefly through books,” the verb is being employed in the sense of happens or is true.
Note.—In the following sentences from Robert Louis Stevenson it is interesting to observe how such a sentence as the one just described comes about: