MODALITY

So far we have considered primary tense forms only in terms of the past and present tenses, with the observation that time reference is not in itself necessarily defined by these terms. Thus the present simple can in fact be used with reference to future or indefinite time, and the past simple may be used to express politeness or hypothesis without reference to a past time.

We have also seen that there is no inflected future tense in English which corresponds to the present or past simple tense forms. However, there is of a course a tense form in English which is generally known as the "future simple" tense. This is formed using the auxiliary verbs WILL and SHALL as operators. These express finiteness, but as with the other modal auxiliary verbs, they do not have an "s" form.

As we saw with the past/present simple tenses, time reference is primarily signified by adverbs. In the following example, there is no future reference although the "future simple" is employed. The modal verb WILL here signifies volition:-

Modality is expressed through the modal verbs which we have already mentioned. It expresses an interpersonal element of meaning in that it is concerned with the speaker's assessment of probabilities, degree of obligation, possibility, prophecy, intention and so on. The modals thus modify the main verb by indicating a range of attitudes and influences concerning the particular process or state concerned.

This wide range of meaning is covered by the modal verbs MAY, MIGHT, MUST, CAN, COULD, NEED, OUGHT, DARE, WILL, SHALL, WOULD and SHOULD. As with the tense system, these verbs are commonly used in combination with adverbs to which they relate, in this case those which typically convey corresponding semantic notions, such as "perhaps", "maybe", "probably" etc.

In describing the features of the verbs which make up this set, grammarians usually distinguish between those verbs which may be characterised as "full" modals, and those which are "quasi" or "marginal" modals. All the verbs listed above are full modals except for NEED and DARE. However, these do function as part of the modal system, although in some respects differently to the other members of the set. Both of these verbs express tense (but only in positive declarative structures), and therefore subject concord, whereas full modals such as MUST, MAY, WILL and so on do not.

The verb USED TO is also treated by some grammarians as marginal. However, for the purposes of this analysis, all these verbs will be regarded as functioning within the system of modality, whether we classify them as "full" or "quasi" modal. This is justified on the grounds that all these verbs can function as operators, and thus share certain specific features which distinguish them from all other verbs, which we can identify as follows:-

All the verbs mentioned above conform to these minimum basic specifications, which will therefore be taken for the purpose of this analysis to be the significant defining criteria of modal verbs. Thus according to this specification, the verbs NEED, DARE and USED TO will be counted as belonging to the set, whereas the marginal auxiliary HAVE TO will not, since it does not conform to specification (3) above. Although this verb functions in some ways identically to other modals, we shall therefore treat it as one of the SEMI-AUXILIARIES such as GOING TO and other expressions, and will be discussed later when we consider medial systems in the verbal group.

The modal verbs comprise a closed set, the selection of one of which excludes any of the others also being included in the same verbal group. The verb NEED is the only exception to this, for it can also occur in medial position in the verbal group (similar to HAVE TO) following certain other modal verbs. This will also be discussed in the section dealing with medial systems.

The verbs NEED and USED TO also have optional negative and interrogative forms using the operator DO.

Modality and meaning

If we leave for the moment the matter of time reference, which is not the principal function of the modal verbs, we see that the modal verbs express a wide range of possible meanings, which grammarians divide into two broad functional categories:-

These two semantic functions may be distinguished by refering to the meanings expressed in (i) as INTRINSIC or INFLUENCE modality, while the expression of probability, possibility, certainty etc is EXTRINSIC or KNOWLEDGE modality.

The communicative functions which are typical of these two categories may be distinguished in that influence/intrinsic modality is typically concerned with actions that direct human behaviour - for instance, in expressing commands, warnings, advice, permission and so on, all functions which serve to influence someone else's behaviour. The speaker may thus be involved in an interactive way, and the speech function itself form part of that behaviour.

The expression of knowledge modality, on the other hand, is typically a cognitive act, an expression of the speaker's expectation or intuition. It is not necessarily or inherently concerned with human control or influence.

The modal verbs themselves cut across these functional categories, and because of the way these diverse communicative functions may be expressed by the same modal verbs, the distinctions are not always clear cut, but tend to overlap. Note the contrasts in the following examples.

Example (4) signifies not futurity but volition.

Example (6) signifies ability.

Both (a) and (b) express the possibility of the event occuring, but the speaker indicates uncertainty. Examples (c) and (d) similarly express the possibility of the event, but the speaker assesses this as probable. In example (e), the speaker simply asserts that this event will occur, and expresses his certainty of this outcome. In a sense, all statements such as (e) which refer to events in the future involve prediction at the certainty end of the semantic continuum.

Assessments of probability are not of course restricted to future events, as the following examples show:-

Example (i) means possible but uncertain, (ii) is probable, (iii) is certain, and (iv) expresses logical necessity.

Because of the overlapping between the intrinsic and extrinsic meanings, it is not always clear which function is predominant. For instance, WILL can express both intention and prediction.

Thus we can say that (a) expresses intention or volition, (b) is a prediction, and (c) signifies both volition and prediction.