English grammar - Roger Berry 2012

B6.3 Meanings of modal verbs
B6 Modal auxiliaries
Section B Development

We can distinguish two basic types of modality that apply to all the modals:

□ intrinsic modality, referring to human control over events, to do with notions such as permission, obligation or volition (e.g. intentions or promises)

□ extrinsic modality, referring to our perception of the factual nature of events, e.g. possibility, necessity, prediction, deduction.

For example, if you say he must go, this is intrinsic modality; you are imposing an obligation. However, if you say he must be crazy, this is extrinsic modality; you are making a deduction (there is no obligation to be crazy!). However, if you say

You must be crazy to work here

it could mean two things: ’it is necessary to be crazy to work here’ (intrinsic) or ’I think you are crazy to accept a job here’.

We can also group the central modals into three basic groups, according to the general meanings that they indicate. Combining this with the intrinsic/extrinsic distinction, we can arrive at the following table:

Table B6.3.1 Modal auxiliaries: intrinsic and extrinsic meanings

This is a simplification, however, of the meanings of modals, and does not capture all of the nuances and differences. For example, formality is a factor in the use of may and can for permission: you may go now is more formal than you can go now. And would often has an idea of hypotheticality:

I would do it (but I don’t have the time).

And we need to mention one very important meaning of can that does not fit neatly into the table, namely ability: I can do it. Thus a single modal may have a number of different meanings.

The readings in D6 and D10 describe two areas where modals play an important role: in academic and interpersonal communication respectively.

Activity B6.2

Work out the different meanings of can in these sentences.

1. You can go now.

2. She can sing very beautifully.

3. It can be done.

4. Can you talk to him?

5. It can be quite cold at this time of year.

6. I can see absolutely nothing.