Types of modality

Before you tackle this guide, you should be confident that you are
familiar with the contents of
the
essential guide to modality and
the guide to pure
modals.
What follows is an analysis which can be used when planning to teach
modal verbs in English. It is based on some fundamental
concepts in logic and the theory is that the categories of modality
mirror the categories of human thought, making concepts clearer and
more teachable.
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4 shades of modality |
- epistemic modality
- Epistemology is the study of theories of knowledge and the
word epistemic means relating to knowledge.
This kind of modality is to do with the speaker's perception of the truth or otherwise of a proposition. So, for example, on hearing a knock at the door, the use of will in
That will be the postman
signals the speaker's certainty about the proposition. Equally:
That can't be the postman
signals the speaker's certainty of untruth and the use of might in
That might be the postman
signals the speaker's uncertainty.
Modal verbs of deduction fall into this category. - deontic modality
- Deontology is the study of duty and deontic means
relating to obligation and duty (or its lack). For example, the use of
ought to in
You ought to write to your mother
expresses the speaker's perception that it is the hearer's duty to write and the use of must in
You must not write like that
expresses the speaker's view that the hearer is obliged not to write in that way.
The use of may in
You may go
expresses the speaker's view that there is no longer a duty or obligation to stay.
Modal verbs expressing any sense of obligation or its lack fall into this category. - dynamic modality
- The term dynamic needs no explanation but here it
refers to the fact that the modality is centred on the subject.
For example, the use of could in
I could swim well as a child
refers to the subject's own ability and not to externally imposed obligations or duties and the use of can in
Can you help me with this?
refers to the hearer's ability alone and
I'll get it for you
refers to the speaker's willingness to do something (volition). It is not, incidentally, a future tense form and does not necessarily refer to the future at all; it is an expression of current willingness to do something. - alethic modality
- This term derives from the Greek word for truth
[αλήθεια, aleethia] and refers to logical necessity (rather than
deduction which concerns epistemic modality). For example, the use of must in
A square must have four sides
refers not to the speaker's perception and not to any form of obligation or deduction but to the fact that one of the necessary conditions of being a square is to have four sides and the use of can't in
Parallel lines can't meet
equally represents the truth of a proposition failing which, the lines cannot be parallel.
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An alternative view of modality |
With this analysis in mind, we can try an alternative way to represent the diversity of modal verbs in English. The usual analysis (used elsewhere on this site in the consideration of modals) is to take each verb in turn and then itemise and explain what functions they can perform. For example, from the guide to pure modals, we have something like:
might
Function | Example |
present possibility | Careful. There might be a snake in the hall. |
future possibility | It might rain tomorrow. |
past possibility | He might have telephoned while I was out. |
suggestion | You might try taking an aspirin. |
permission | Might I talk to you? |
complaint | You might have warned me! |
This is clear and quite concise but, for teaching purposes, is a flawed way to see the analysis. Speakers of the language do not proceed from a consideration of the various functions of the verb and then make meaning using it. What they do is to conceive a meaning and then select a modal expression which suits their purposes.
For example, I may have in mind the fact that I do not believe
Mary when she says:
Hey, I saw a unicorn on my way back from the pub last night!
For my purposes, I might select any number of expressions of
modality depending on my degree of certainty, formality, setting and
so on. I may consider, for example:
It's an impossibility that you saw a unicorn
You can't have seen a unicorn
It is impossible that you saw a unicorn
I suppose you might have seen a unicorn, but I doubt it
You couldn't have seen a unicorn; they don't come round here
and so on.
These examples are forms of epistemic modality (i.e., to do with the speaker's view of the truth of a proposition) although the verbs and expressions themselves can be used to express other types of modality. They all express a degree of certainty about the central proposition.
Now we can revisit our original 11 pure modals (from the other guide) and re-analyse them from the point of view of these four categories.
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An alternative analysis of modality |
The following is not meant to be exhaustive but, for most
English-language teaching purposes, it will suffice as a starting
point when planning to teach modality based on mental
processes rather than form.
The alternative modal expressions are suggestive only and include
modal adverbials, nouns and adjectives.
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epistemic modalityThat must be the teacher's desk |
Modal verb | Example | Alternative modal expressions |
might | If there's too
little current, the pump might not work. He might have telephoned while I was out. |
It's
possible the pump isn't working. Possibly, he's already gone out. I'm assuming the pump isn't broken. My assumption is that that's the postman. I'm sure that is what he said. It's obviously his brother. It's clear they are related. It seems likely that it's him. I doubt she is there. |
could | It could rain tomorrow. He couldn't have gone out this early. |
|
can | The pump can't be broken. It's new. | |
should | Ah, that should be the postman now. | |
would | Well, he would,
wouldn't he? It's in his interests. That would be his mother you saw. |
|
must | That must be his brother. Aren't they alike? | |
may | Well it may be his brother. I don't know. | |
will | That will be the postman at the door. | |
ought to | She ought to be there by now. |
For more on how epistemic modality is expressed in English, see the guide to expressing (un)certainty and the fuller guide to epistemic modality.
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deontic modalityThey shall not pass. |
Modal verb | Example | Alternative modal expressions |
might | Might I ask a question? | Is
there a chance of asking a question? Do you have a moment? Seeing a doctor would be advisable. I forbid you to speak to me like that. Is he allowed to come, too? Do you have permission to be here? If I were you, I'd see a dentist. It's her duty to write. Registration is compulsory. I advise you to leave soon. |
could | Could I just say something? | |
can | Can I see you for a minute? | |
should | You should not
speak to me like that. You should see a doctor. |
|
must | You must finish the work before 6. | |
may | May he come with us, please? | |
will | You will not speak to me so rudely again. | |
ought to | She ought to write to her father. | |
have (got) to | You have (got) to register online. | |
had better | Hadn't you better leave soon? | |
shall | You shall not speak to your father like that |
In some of the above, of course, there is an implied reference to
possibility (i.e., epistemic modality). For example,
Do you have a moment?
can be interpreted as a question about a
current state but is more likely to mean
Do you give me
permission to interrupt your day?
and
Registration is compulsory
can be interpreted simply as a
statement of fact but is more likely to mean
You have to
register.
For more on how deontic modality is expressed in English, see the guide to expressing obligation and the fuller guide to deontic and alethic modality.
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dynamic modalityWe can do this! |
Strictly speaking, dynamic modality is confined to expressions of ability or willingness. That will limit the number of verbs quite severely to can, could, will, would and be able to for the most part.
Modal verb | Example | Alternative modal expressions |
can | I can speak Spanish well. | She has
the ability to speak 4 languages. I haven't the strength to do it. I am happy to accept. I volunteer to do that Let me go, I know the way Did you manage to find what you wanted? |
could | I couldn't possible
lift it. She could read well at the age of 4. |
|
will | I'll get the door. | |
would | I would love to come. | |
able to | Were you able to find what you wanted? |
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alethic modalityThe blue bit can't go here. |
Modal verb | Example | Alternative modal expressions |
must | A quintet must contain 5 players. | Unless
it has five players, it's not a quintet. Having more than 8 players disqualifies it as an octet. It is necessary to have 4 sides in a square. |
can't | An octet can't have more or fewer than 8 players. | |
need | A square needs 4 sides. |
When expressing alethic modality, the verb must is negated in standard English as can't or couldn't (as it is for epistemic modality). In some dialect forms, however, mustn't is used to express impossibility rather than negative obligation.
The guide to expressing degrees of likelihood includes considerations of alethic modality and considers the overlap between it and epistemic modality.
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Notes |
- In some analyses, the modal verb must is classified as representing intrinsic or even dynamic modality because it is seen as personal to the speaker rather than an externally imposed duty and have to appears under extrinsic deontic modality because, the theory has it, that it expresses an externally imposed duty. However, where it is not obvious which is intended, native speakers use them in free variation.
- The strength of both deontic and epistemic modality is often determined by intonation and stress rather than depending on the modal expression chosen by the speaker.
- In this analysis, logical deduction and logical necessity are distinguished (as epistemic and alethic modalities) but, for most teaching purposes, can be conflated.
- The verb need is treated here as a central modal although it has semi-modal characteristics in many cases.
- Teaching modal expressions using this kind of analysis
presumes that you start from the type of modality your learners
need to express and work on a limited range of ways to realise
the mental processes in English.
There is a guide on this site to teaching modality.
Here's a summary with examples using pure (or central) modal
auxiliary verbs only. Semi-modal verbs and marginal modal
verbs can also express different types of modality. All four
types of modality can also be expressed without modal auxiliary
verbs at all.
For teaching purposes, the summary is useful because you can see at
a glance whether the lesson you planned mixes the same verb
expressing different forms of modality. That can confuse,
especially at lower levels.
To check your understanding, try a multiple choice quiz on this area.
Related guides | |
essential guide to modality | a simpler guide in the initial training section |
pure modals | a traditional view taking each modal in turn and identifying its function |
semi-modal verbs | which also considers marginal modals such as seem, tend, be about to etc. |
non-modal verb modality | which considers adverbials, verbs, adjectives and nouns used to express modality |
epistemic modality | modality for expressing the speaker's view of the truth or a proposition, i.e., likelihood |
expressing uncertainty | a functional approach to epistemic modality |
deontic modality | modality for expressing the speaker's view of obligation or its lack |
dynamic modality | modality for expressing ability and willingness |
time, tense and aspect | the place to go if the distinctions between, e.g., perfect and perfective, continuous and progressive are obscure |
complex tenses | which also considers complex tenses in relation to modality |
teaching modality | for some more ideas transferable to the analysis above |
tense and aspect | which consider modal verbs with perfect and progressive forms and considers some of the types of modality discussed here |
Reference:
Palmer, F. R, 2001, Mood and Modality, 2nd
ed., Cambridge: Cambridge University Press