[Grammar] must / have to

I often wondered how the verb "must" cannot be made to work in the past tense and to express an obligation in the past tense an expression "to have to" needs to be used.

Can the construct "must have" be looked upon as a way around this constraint of "must"?

To explain more clearly what I mean here's an example:

"I must be out of my mind to call her" = "I have to be out of my mind to call her" which I suppose means "the fact of my calling her is a proof of my insanity"

and in the past

"I must have been out of my mind to call her" = "I had to be out of my mind to call her"

Does this theory hold water or am I out of my mind to even think so?

"I must be out of my mind to call here."

There is no obligation here - it is a statement of logical certainty about a situation. If the situation is past, then we say, "I must have been out of my mind".

If we want to describe a past obligation that was fulfilled, then we say, "I had to (e.g., be at the office by seven)"

JarekSteliga said:

I often wondered how the verb "must" cannot be made to work in the past tense and to express an obligation in the past tense an expression "to have to" needs to be used.

Can the construct "must have" be looked upon as a way around this constraint of "must"?

To explain more clearly what I mean here's an example:

"I must be out of my mind to call her" = "I have to be out of my mind to call her" which I suppose means "the fact of my calling her is a proof of my insanity"

and in the past

"I must have been out of my mind to call her" = "I had to be out of my mind to call her"

Does this theory hold water or am I out of my mind to even think so?

Click to expand...

All your examples mean exactly what you think they do. So they all refer to the act of phoning being proof of your insanity whether in the present or the past.

JarekSteliga said:

I often wondered how the verb "must" cannot be made to work in the past tense and to express an obligation in the past tense an expression "to have to" needs to be used.

Can the construct "must have" be looked upon as a way around this constraint of "must"?

To explain more clearly what I mean here's an example:

"I must be out of my mind to call her" = "I have to be out of my mind to call her" which I suppose means "the fact of my calling her is a proof of my insanity"

and in the past

"I must have been out of my mind to call her" = "I had to be out of my mind to call her"

Does this theory hold water or am I out of my mind to even think so?

Click to expand...

I think you're confused. Your use of "I must have been out of my mind" does not express obligation.
Let's say you want to talk about obligation in the past. You wanted to get into a psychiatric hospital (Don't ask me why). But they wouldn't admit you unless you were out of your mind. So you had an obligation to be out of your mind if you wanted admission.
You can't say, "I must have been out of my mind for them to admit me".
You have to say, "I had to be out of my mind before they would consider admitting me", or "I would have had to have been out of my mind before they would consider admitting me".

PS: I seem to remember a construction with "must needs be" from old novels; and there is this line from Walter Scott: "He was haunted by two evil spirits ... who, even upon the scaffold, were disturbing him by inhumane interrogatories, when he had must need to have had his thought in best repose."
http://books.google.com.au/books?id=aZshAQAAMAAJ&pg=PA448&lpg=PA448&dq="had+must+need"&source=bl&ots=JHj9PZ3BcI&sig=nco0RzPJHonA_vPbKepnzQpRqgE&hl=en&sa=X&ei=0hIVT5bKK8a0iQeg1JBD
I couldn't guarantee that this isn't a typo for "had most need". If it is genuine, then it's possible that in the past, it was possible to say "I had must need be mad before they would admit me", or something similar. But maybe I'm going mad. In any case, it's not allowed in modern English.

PS: I seem to remember a constructions with "must needs be" from old novels; and there is this line from Walter Scott: "He was haunted by two evil spirits ... who, even upon the scaffold, were disturbing him by inhumane interrogatories, when he had must need to have had his thought in best repose."
http://books.google.com.au/books?id=aZshAQAAMAAJ&pg=PA448&lpg=PA448&dq="had+must+need"&source=bl&ots=JHj9PZ3BcI&sig=nco0RzPJHonA_vPbKepnzQpRqgE&hl=en&sa=X&ei=0hIVT5bKK8a0iQeg1JBD
I couldn't guarantee that this isn't a typo for "had most need". If it is genuine, then it's possible that in the past, it was possible to say "I had must need be mad before they would admit me", or something similar. But maybe I'm going mad. In any case, it's not allowed in modern English.[/QUOTE]

I am very glad that I haven't stumbled upon this particular sentence by Walter Scott, because if I had, I would for sure not have been able to make heads or tails of it.

I am equally glad (as I am sure all my fellow learners are) to see the back of sentences like "I had must need be mad". Bye the way, did not Scott use "clothed" infinitive instead of bare infinitive?

Raymott said:

I think you're confused. Your use of "I must have been out of my mind" does not express obligation.
Let's say you want to talk about obligation in the past. You wanted to get into a psychiatric hospital (Don't ask me why). But they wouldn't admit you unless you were out of your mind. So you had an obligation to be out of your mind if you wanted admission.
You can't say, "I must have been out of my mind for them to admit me".
You have to say, "I had to be out of my mind before they would consider admitting me", or "I would have had to have been out of my mind before they would consider admitting me".

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Let us look at a different example: "I do not have the keys in my pocket so I must have left them in the car"

I quite understand that I could not say: "I do not have the keys in my pocket because I must have left them in the car" meaning "I do not have the keys in my pocket because I was obliged/told/forced etc. to leave them in the car or forbidden from taking them from the car"

Still could not the phrase "...must have left them..." in the original sentence be not looked at as an obligation, except a different kind of obligation? I know this goes far and perhaps beyond the reasonable, but I would suggest that obligations for the sake of our current discussion should be divided into two categories:

1. An obligation towards or because of a human being or human related.
2. An obligation towards logic or logical inference or mathematical axiom etc.

The phrase "had to" covers both kinds of obligation, while the phrase "must have ..PP" only the second.

What do you think?

emsr2d2 said:

All your examples mean exactly what you think they do. So they all refer to the act of phoning being proof of your insanity whether in the present or the past.

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Thank you. It is now just a wild theory related to this - which I took the liberty of unleashing - which alarmed other members of the forum.

5jj said:

"I must be out of my mind to call here."

There is no obligation here - it is a statement of logical certainty about a situation. If the situation is past, then we say, "I must have been out of my mind".

If we want to describe a past obligation that was fulfilled, then we say, "I had to (e.g., be at the office by seven)"

Click to expand...

Thank you

JarekSteliga said:

Let us look at a different example: "I do not have the keys in my pocket so I must have left them in the car"

I quite understand that I could not say: "I do not have the keys in my pocket because I must have left them in the car" meaning "I do not have the keys in my pocket because I was obliged/told/forced etc. to leave them in the car or forbidden from taking them from the car"

Still could not the phrase "...must have left them..." in the original sentence be not looked at as an obligation, except a different kind of obligation? I know this goes far and perhaps beyond the reasonable, but I would suggest that obligations for the sake of our current discussion should be divided into two categories:

1. An obligation towards or because of a human being or human related.
2. An obligation towards logic or logical inference or mathematical axiom etc.

The phrase "had to" covers both kinds of obligation, while the phrase "must have ..PP" only the second.

What do you think?

Click to expand...

I think it's far easier to use the conventional understanding that "obligation" refers to 1. only.

Besides, you're making an even worse error, I think. 2. only refers to obligation in the sense that any grammatical construction is obliged to follows the rules of the language, regardless of whether the meaning is one of obligation of not. For example, if your rule was valid, other modals, such as 'can' and 'would' would also relate to obligation, because you're obliged to use them in some cases.
"That can't be Mary. Mary is blonde". Are you going to assert that "can't" also relates to obligation because it's a logical inference? How about, "It might be Mary". This is an obligation to concede the possibility that the person is Mary.

Raymott said:

I think it's far easier to use the conventional understanding that "obligation" refers to 1. only.

Besides, you're making an even worse error, I think. 2. only refers to obligation in the sense that any grammatical construction is obliged to follows the rules of the language, regardless of whether the meaning is one of obligation of not. For example, if your rule was valid, other modals, such as 'can' and 'would' would also relate to obligation, because you're obliged to use them in some cases.
"That can't be Mary. Mary is blonde". Are you going to assert that "can't" also relates to obligation because it's a logical inference? How about, "It might be Mary". This is an obligation to concede the possibility that the person is Mary.

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You have quite convinced me that it is far easier to use the conventional understanding of "obligation" and at this stage of the discussion give the matter a rest.

However your example sentence leads me to another question (beside the topic).

"That can't be Mary. Mary is blonde"

My question is how to transpose these two to past tense.

"That couldn't have been Mary. Mary was blonde" using the past form of the modal 'can'
or
"That can't have been Mary. Mary was blonde" following the analogy of 'must' and leaving the modal in its present form.

In the past tense:

"I must have been out of my mind to call her" = "It's quite possible I was out of my mind when I called her"
"I had to be out of my mind to call her"
=
1) "I was allowed/had a chance to call her only when/if I was out of my mind"
2) "It's quite possible I was out of my mind when I called her" (as is the case with "must"; used in American English)

Bennevis said:

In the past tense:

"I must have been out of my mind to call her" = "It's quite possible I was out of my mind when I called her"
"I had to be out of my mind to call her"
=
1) "I was allowed/had a chance to call her only when/if I was out of my mind"
2) "It's quite possible I was out of my mind when I called her" (as is the case with "must"; used in American English)

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Thank you, but I do not quite agree with your "equations". In my opinion the meaning of the first sentence "I must have been out of my mind to call her" is "It's quite certain I was out of my mind when I called her"
and the meaning of the second sentence "I had to be out of my mind to call her" is also "It's quite certain I was out my mind when I called her"

Conversly, your sentence "I was allowed/had a chance to call her only when/if I was out of my mind" would be synonymous to "I had to be out of my mind to be allowed to call her" or better still "I had to be out of my mind in order to be allowed to call her" meaning that "I would not have been allowed to call her if I had not been diagnosed as insane":-?

JarekSteliga said:

Thank you, but I do not quite agree with your "equations". In my opinion the meaning of the first sentence "I must have been out of my mind to call her" is "It's quite certain I was out of my mind when I called her"
and the meaning of the second sentence "I had to be out of my mind to call her" is also "It's quite certain I was out my mind when I called her"

Conversly, your sentence "I was allowed/had a chance to call her only when/if I was out of my mind" would be synonymous to "I had to be out of my mind to be allowed to call her" or better still "I had to be out of my mind in order to be allowed to call her" meaning that "I would not have been allowed to call her if I had not been diagnosed as insane":-?

Click to expand...

Well, an Englishman liked my post. Perhaps, that's the way the sentences make one feel. ;-)

JarekSteliga said:

Thank you, but I do not quite agree with your "equations". In my opinion the meaning of the first sentence "I must have been out of my mind to call her" is "It's quite certain I was out of my mind when I called her"
and the meaning of the second sentence "I had to be out of my mind to call her" is also "It's quite certain I was out my mind when I called her"
No, it's not quite certain. It's as certain as the speaker can be as a result of logical deduction.

Conversly, your sentence "I was allowed/had a chance to call her only when/if I was out of my mind" would be synonymous to "I had to be out of my mind to be allowed to call her" or better still "I had to be out of my mind in order to be allowed to call her" meaning that "I would not have been allowed to call her if I had not been diagnosed as insane":-?
Yes.
Bennevis's reading is not one that immediately springs to mind, but is indeed possible. It doesn't work without more context, but then few utterances do.

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5

JarekSteliga said:

I often wondered how the verb "must" cannot be made to work in the past tense and to express an obligation in the past tense an expression "to have to" needs to be used.

Can the construct "must have" be looked upon as a way around this constraint of "must"?

To explain more clearly what I mean here's an example:

"I must be out of my mind to call her" = "I have to be out of my mind to call her" which I suppose means "the fact of my calling her is a proof of my insanity"

and in the past

"I must have been out of my mind to call her" = "I had to be out of my mind to call her"

Does this theory hold water or am I out of my mind to even think so?

Click to expand...

A couple of points that may be of interest:

1. 'Must' is, in origin, a past tense (corresponding to a long extinct present-tense form 'muss') which has evolved to have an almost exclusively present meaning. Its origins are betrayed only in indirect speech, where, in common with other etymologically past-tense forms 'should', 'would', 'could' and 'might', it occurs without backshift, e.g.

Napoleon never stopped believing that England must be defeated.

2. The form 'must have' - technically a perfective rather than a true 'past' form - functions nonetheless as a de facto past tense but only in the EPISTEMIC sense of 'must' (i.e. denoting logical inference). As regards DEONTIC 'must' (denoting obligation), the suppletive form 'had to' is used, although this latter can also serve epistemically and is therefore probably a 'safer' form for the learner.

philo2009 said:

A couple of points that may be of interest:

1. 'Must' is, in origin, a past tense (corresponding to a long extinct present-tense form 'muss') which has evolved to have an almost exclusively present meaning. Its origins are betrayed only in indirect speech, where, in common with other etymologically past-tense forms 'should', 'would', 'could' and 'might', it occurs without backshift, e.g.

Napoleon never stopped believing that England must be defeated.

2. The form 'must have' - technically a perfective rather than a true 'past' form - functions nonetheless as a de facto past tense but only in the EPISTEMIC sense of 'must' (i.e. denoting logical inference). As regards DEONTIC 'must' (denoting obligation), the suppletive form 'had to' is used, although this latter can also serve epistemically and is therefore probably a 'safer' form for the learner.

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If I were to say that your "couple of points" were of interest to me, I would be making a huge understatement. I feel truly enlightened. Thank you very much.

JarekSteliga said:

If I were to say that your "couple of points" were of interest to me, I would be making a huge understatement. I feel truly enlightened. Thank you very much.

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