In a recent post entitled Energy, we looked at the principle of preferring verbs to nouns in revising a sentence. A prepositional phrase, for example, often hides a good, strong verb in its object (the verb collapsed in the phrase after the bridge collapse), and abstract nouns likewise not uncommonly conceal a transitive verb (the verb inspected from the noun inspection) that can rework a sentence substantially. This latter change is worth considering more closely, because it can involve revising a sentence to a degree we don’t always expect.
Our original illustration was this awkward sentence: After the bridge collapse, there was an inspection by an engineering firm which was hired by the state, and one of the revisions we ultimately arrived at was After the bridge collapsed, an engineering firm inspected the scene to determine the cause. We can see the change from inspection to inspected, but the revision includes six words after that verb which are nowhere to be seen in the original. Those words fill out the predicate that was created by preferring the transitive verb inspected over its abstract noun inspection, replacing another prepositional phrase (by an engineering firm) and adding new relevant detail (to determine the cause). This new detail involved another kind of verbal construction we should understand to better our work.
The two words to determine constitute what is called an infinitive, a form of a verb very different from what we normally mean when we try to find the verb of a clause. The word infinitive means unspecific, and in grammar that means that it does not have a subject that is doing something at a particular time and in a particular way—all of which we expect from what we normally call a verb. We will say, for example, that an engineering firm will determine the cause of the collapse, and with the verb will determine, we see the subject engineering firm and the auxiliary verb will, which tells us the verb is in the future tense and indicative mood. Subject, tense, mood—all of that is quite specific, and that is why what we usually mean when we think of a verb is what is more exactly known as a finite verb, a verb specific as to its subject and the actual time of its action. Every clause must have a finite verb to operate because finite verbs are specific in exactly the way infinitive verbs are not.
But infinitives are still verbs, and so including them in the predicate of a clause can keep us close to our principle of preferring verbal constructions in composing a sentence. Infinitives (along with participles and gerunds) are hybrids; they work as nouns or adjectives or adverbs, but they are built from verbs. And because they derive from verbs, they carry with them all the strength and vigor of their verbal ancestors, having their own relative time and targeting their meaning at objects, just as transitive finite verbs do. So when we find ourselves converting the abstract noun inspection into the verb inspected, we also discover that we have put ourselves unwittingly into a position where we have to complete the thought of inspected. We have to think more specifically, and that we do, in turn, with the help of the infinitive to determine, which then renews the demand that we complete the thought this infinitive has now set up: we must tell what it is the engineering firm is to determine, namely, the cause. (And note, importantly, not the cause of the collapse, but simply the cause, because we have every right to assume that the reader has not forgotten in so brief a span of time that we are talking about the collapse of a bridge.)
Using infinitives, then, can keep us in accord with an important principle of writing and help us fill out a thought that may have been too compact and too assuming in the original. Very often we believe the reader knows what we are thinking, and revising with close attention to verbal constructions can bring much good detail energetically to light.