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Placing “is” (or other form of BE) directly before a verb with “to” can express various meanings
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THE IMPORTANCE OF “to” VERBS IN ENGLISH
Verbs with “to” – usually called “infinitives” – have such a wide variety of uses in English that a reader of this blog once asked me to survey them all. However, I have not been willing to do this because it is common in mainstream grammar descriptions, and hence is not the sort of less-commonly analysed topic that the blog seeks to be about.
More interesting to me are specific uses of the infinitive that I have noticed to be troublesome for at least some users of English who do not speak it as their mother tongue. Other parts of this blog have indeed focussed on some of these, in particular 35. “To Do” versus “To Doing”, 60. Purpose Sentences with “For”, 78. Infinitive versus Preposition after Nouns, 83. Active Verbs with Non-Active Meanings 2 and 103. Sentences Starting with “it”.
The use of an infinitive after the verb BE is a similarly interesting aspect of infinitive usage. There seem to be at least eight different meanings that this combination can create, and it is these that the present post is about. Some are possible with any form of BE, while others require very specific forms.
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INFINITIVES THAT MAY FOLLOW ANY FORM OF be
Most of the infinitive meanings are in this category. Each seems recognizable mainly from the words used before BE.
1. Purpose-Naming
Examples of this use are:
(a) The purpose of speed cameras is to prevent road accidents.
(b) The prize is to attract more people.
In the first of these, the subject of BE includes the word purpose, thus leaving no doubt that the infinitive also has that meaning. Synonyms like aim, intention, objective, plan and target are also possible. Sentence (b), on the other hand, shows that such a word is not always necessary. The idea of purpose can seemingly still be understood purely on the basis of world knowledge – in this case the common observation that attracting more people is a frequent purpose of a prize. The importance of world knowledge for recognising meanings is indicated elsewhere within this blog in posts like 18. Relations Between Sentences and 107. The Language of Opinions.
Nevertheless, the absence of any specific language to indicate the meaning of purpose can, given the existence of other possible meanings of BE + infinitive, create double meanings. Sentence (b) could, for example, be understood as saying that attracting more people was the prize itself rather than its purpose (see category 6 below).
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2. Function-Naming
Functions are not the same as purposes but they are very like them. They are behaviours that particular people or things are expected by definition to perform, but they do not have to be desired by living creatures as purposes do (see 60. Purpose Sentences with “For”). A typical function sentence might be:
(c) The function of a volcano is to release pressure within the earth’s crust.
The behaviour here is not related to the desire of any living creatures at all. Contrast this with sentence (a), where the subject speed cameras is also non-living, but the associated behaviour is very much a human desire.
Function statements do not always have to have a non-living subject. Consider this:
(d) The function of doctors is to cure or alleviate human sickness.
The meaning here is different from what it would be with purpose instead of function: information is given about what doctors are expected to do but not about what doctors themselves are trying to achieve – their purpose. This might be the same as the function, but it could also be completely different – to have a comfortable life, for example, or to be popular.
Function statements with BE + infinitive seem to need a word like function or role near the start to assist their recognition.
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3. Method-Naming
A method is an action undertaken in order to achieve a purpose. It is the usual meaning of by combined with an -ing verb (see 73. Saying How with “By” and “With” and 101. Add-On Participles). An infinitive becomes an alternative to this combination in sentences like the following:
(e) The best way to learn a language is to live amongst its speakers.
It would also be correct here to say by living. The key requirement for BE + infinitive to be method-naming seems to be having the word way (or, rarely, a synonym such as method) as subject.
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4. Arrangement-Stating
This use of BE + infinitive may be illustrated as follows:
(f) A meeting of finance ministers is to be held in Brussels.
(g) The armies were to converge on the plain at midday.
The meaning here seems to involve two elements: futurity and the influence of other people. The first may be relative to now – shown by a present tense of BE, as in (f) – or relative to a different time – the past in (g). The influence of other people in an arrangement is that they must either agree to its happening or command it. It is the infinitive verb after BE that indicates the agreed or commanded future action: holding a meeting in (f) and converging on a plain in (g). When an action has been commanded, the use of BE + to closely resembles HAVE + to. The difference is that HAVE leaves the influence of other people unconfirmed.
The main clues to the existence of this meaning seem to be (I) the absence of a word like purpose, function or way in the subject of the sentence, (II) capability of the subject regarding the infinitive verb’s action, and (III) ease of arranging the infinitive verb’s action. Sentences (f) and (g) meet all of these conditions. Sentences (b) above and (k) below fail on (III) (attracting people and becoming an emperor are not easily arranged), while (i) below fails on (II) (a prize cannot usually perform a visit).
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5. Equivalence-Showing
Sentences of this kind have an infinitive verb before BE as well as after:
(h) To think is to exist.
The two infinitive meanings here are exactly equal: either one implies the other. The meaning of the subject of the sentence (to think) is not being identified or clarified by the later infinitive in the way discussed in the post 117. Identifying after a Description.
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6. Clarifying
In this use, subject-clarification does exist. It is similar to what happens in sentences (a), (c) and (e) above, but there is no special subject noun like purpose, function or way: the subject needs only to indicate action of a very general kind, like this:
(i) The prize is to meet a world-famous researcher.
Prizes do not have to be actions, but they very often are. The infinitive and its object here tell us what the prize is. Other very general action-indicating nouns that an infinitive could clarify include challenge, effect, next step, outcome, possibility, procedure and task. In contrast, meeting in (f) is a less general action, and armies in (g) is not an action at all.
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INFINITIVES THAT FOLLOW A SPECIFIC FORM OF be
Two common meanings in this category are what I call unlikely future and destiny in the past.
1. Unlikely Future
This is the use of were to after if (see 118. Problems with Conditional “if”), as in sentences like this:
(j) If aliens were to visit the earth, great excitement would prevail.
The suggestion here is that the future arrival of aliens is unlikely. Likely futures need the present simple tense after if, and will with the other verb. The word were is the only form of BE allowed in the unlikely future use, even when its subject is singular. The reason is that it is not the usual were but the special one known as the “subjunctive”, which never changes.
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2. Destiny in the Past
This kind of sentence also needs a past tense form of BE, e.g.:
(k) Augustus was to become Roman Emperor six years later.
The infinitive here indicates a future life event – destiny – of a person or thing in the past (the subject of the sentence). There is a resemblance to sentences like (g), where the future event is an arranged plan. As mentioned above, however, this latter meaning is unlikely in (k) because arranging to become an emperor is not easily done by common people, especially six years beforehand.
