Must vs have to

[mysina]

Hello. I would like to ask you about the correct usage of have to and must. In all the English grammar books I have at home (Cambridge University Press, Oxford University Press, Longman) I found the following rule: Must is personal and is used to express an obligation that involves the speaker´s opinion. Have to is more objective and expresses a general obligation based on a law or rule or authority of another person. For example: I must do some more work because I want to pass my exam. (my opinion), In my job I have to work from nine to five. (rule), I must stop smoking. (my opinion), I have to stop smoking (my doctor´s order)

The problem is that in the previous threads dealing with must and have to I found that most native speakers have never heard of this rule and say it´s not true, that the usage of these two verbs is totally different in common English and this rule exists just in the textbooks written for non-native English learners. Could you please give me some advice how it really works? Does this rule exist or not? Thank you.

 

[JulianStuart]

It's certainly not a rule native speakers are taught! (Well, at least not this one!)

In many situations I see them as equivalent:
I must do some more work because I have to pass this exam.
I have to do some more work because I must pass this exam.
(Doing more work and passing the exam are equally urgent.)

I am having difficulty coming up with a "rule" about my usage that clearly says that in situation X I will use must and situation Y I will use have to.

These pairs don't carry different meanings for me:

I must go now or I'll be late for my appointment.
I have to go now or I'll be late for my appointment.

My doctor says I must give up smoking.
My doctor says I have to give up smoking.

It's possible other native speakers follow your rule, but I don't think I do.

 

[hyperslow]

Sorry I know it's a bit lengthy but worth reading. Excerpt taken form English Grammar, A University Course

Must as a modal of obligation
When realised by must, obligation can have the force of a direct command, as in 1 and 2, although modal lexical verbs are more explicit. Compare You must go with I order you to go, I urge you to go.
1 You must try harder.
2 You must copy this out again.
This force derives from the fact that (a) in certain cultural contexts such as school, family, the Armed Forces, the speaker has authority over the addressee, who is the subject ‘you’; (b) the speaker takes the responsibility for the action being carried out; and (c) the verb is agentive and in active voice.
Of the lexical-modals, have to is objective (the obligation is external) and have got
to/gotta subjective (the obligation is internal). Compare 2 and 3
2 I’ve got to go now. (I gotta go now) (the obligation is internal)
3 I have to go and see the Dean. (the obligation is external)

The choice of one form rather than another reflects a difference in attitude on the part of the speaker.
Textbooks do give us some quidance but it hangs on us what we want to say.

 

[DeiTass]

I learned that clear cut rule when studying British-English grammar; and your choice of grammar books point into that direction. I think American-English grammar rules are more relaxed in that respect.

 

[JulianStuart]

I learned that clear cut rule when studying British-English grammar; and your choice of grammar books point into that direction. I think American-English grammar rules are more relaxed in that respect.

I grew up (and learnt my grammar and spelling) in the UK and have never heard of this rule (I'm a native speaker but not an English teacher). I'm not challenging it - and I think there's something to it, just that in many situations it doesn't matter.

I'll be interested to hear other native speakers' reactions and whether there is a BrE/AmE difference.

 

[mysina]

I can see it´s not easy at all Other native speakers´ opinions would really help.

 

[entangledbank]

I've never heard of this distinction, and also I can't give a simple explanation of my own of what the difference is, but actually the rule you quote sounds quite good. It seems to fit real examples. But it must be taken as a general guide only. Most English-speakers would probably start by saying 'must' and 'have to' are the same. They're not, but there is a lot of overlap. Often you could say both with no difference, or only a small difference.

However, looking through the British National Corpus for real examples of 'must', I find (simplifying the actual examples):

(1) It is very common to use 'must' in the knowledge sense (not the obligation sense that is similar to 'have to'): She must be rich. You must be thinking of somebody else. Philip Roth's book must be on the shortlist. He must be used to it by now.

(2) With external obligations, 'must' sounds far better; 'have to' is sometimes scarcely possible: His trustees in bankruptcy must ask the courts to intervene. Higher costs mean that greater numbers of staff must be employed. UK businesses must therefore know how to comply with this law. Each student must select one from Section B and one from Section C.

With these, when 'have to' is a good alternative it slightly switches the focus to internal obligation: You have to employ more staff (if you want to stay in business). But with the bankruptcy example, the trustees will have to apply to the court if they want something to happen; but they must apply to the court because that is the law, and they have no choice.

 

[mysina]

With external obligations, 'must' sounds far better

With these, when 'have to' is a good alternative it slightly switches the focus to internal obligation: You have to employ more staff (if you want to stay in business). But with the bankruptcy example, the trustees will have to apply to the court if they want something to happen; but they must apply to the court because that is the law, and they have no choice.

Now I´m even more confused. You write that must is used for external obligation and have to for internal obligation. But in all the textbooks it´s quite the opposite

 

[entangledbank]

Oh yes, that's a problem, isn't it? Your original examples were all with subject 'I', and the ones I picked up from the corpus were with third-person subjects. That seems to make a difference then. And second person would be different again. Hmm . . .

 

[mysina]

Oh yes, that's a problem, isn't it? Your original examples were all with subject 'I', and the ones I picked up from the corpus were with third-person subjects. That seems to make a difference then. And second person would be different again. Hmm . . .

Thanks for your answer. It´s more complicated than it seems to be

 

[entangledbank]

Yes, that's interesting. With the same situation, the conditions turn around, depending on person. (I read your examples, nodded at 'external' and 'internal', looked at the corpus, saw an external/internal difference there, and assumed I was agreeing with you. Sorry.) Let's look at me and the bankruptcy example:

I have to ask the courts to intervene. [some external necessity or law compels me]
I must ask the courts to intervene. [it would be a good idea to do that if I want the right result]
and let's add a third nuance:
I'll have to ask the courts to intervene. [I can't see any other way of getting the result]

 

[mysina]

It´s perfectly clear now It always depends on the point of view. Thanks a lot entangledbank.

 

[Merrit]

In the realm of TEFL and TESL, the grammar books regard the distinction between 'must' and 'have to' on the basis of internal/external opinion/obligation as if it were very important. (*1)

Unfortunately, the whole house of cards comes tumbling down when we need to use anything other than the Present Simple.

Since I cannot say 'I will must', 'I musted', 'I am musting' or even 'I would must', it is necessary to use forms of 'have to', regardless of whether the situation is (opinion/obligation), (internal/external) or whatever else.

If we have to use forms of 'have to' in every tense except the Present Simple, I question the value of an arbitrary(*2) distinction between 'must' and 'have to' in that single case. Even more do I question the elevation of this distinction to the level of a grammar "Rule".

(*1) I have no idea if this is true for other areas of English teaching.
(*2) And it does seem arbitrary, if not totally artificial, in view of the number of mother-tongue English-speakers who have never heard of it.

m

 

[SouthDakotaRoman]

I agree with Merrit, as a TEFL teacher, all the books give the "rules" of the original poster, but in real life it comes down to personal choice. Often, it's better to do more listening and reading to understand the way a language is really spoken, than focus on the grammar books (my opinion ).

 

[entangledbank]

For what it's worth, the OED attaches this note of explanation to its sense 3.a., the basic present tense sense of obligation:

In the second person, must now chiefly expresses a command or an insistent request or counsel; in the third person it tends to be restricted to the expression of a necessity which is either imposed by the will of the speaker, or relative to some specified end, or enunciated as a general proposition.

Note 'chiefly' and 'tends'. There is no clear, easy distinction between them, but they are also not always interchangeable. There are definitely some circumstances where one or the other is preferable, and the guidance in grammar books and the OED is an attempt to capture an approximate summary of when we use one or the other.

 

[mysina]

In Online Oxford dictionary I found that have to is more common in North American English, especially in spoken English. It always says that in British English there´s a difference between have to (rules, laws...) and must (speaker´s wishes).

 

[Englishmypassion]

It always says that in British English there´s a difference between have to (rules, laws...) and must (speaker´s wishes).

I have to disagree with that black-and-white distinction of laws versus the speaker's wish - - it's not so simple.

(Sorry for posting in this old thread - - I couldn't help.)

 

[JulianStuart]

I have to disagree with that black-and-white distinction of laws versus the speaker's wish - - it's that so simple.

(Sorry for posting in this old thread - - I couldn't help.)

Perhaps mysina really meant "also" not "always"? In any case, I agree that any such comment is intended as a general guidance or tendency rather than a black-and-white rule

 

[pacadansc]

I have to disagree with that black-and-white distinction of laws versus the speaker's wish - - it's not so simple.

I agree. It's not so simple. I also agree with SouthDakotaRoman that grammar books are not always the last word. They often contain mistakes and sometimes disagree. In American English, I rarely if ever hear someone say "I must go to the doctor." or "I really must do this today." Perhaps it sounds too formal. What I hear is "I have to go to the doctor." or "I really have to do this today. Obligation implied.