The use of past perfect "have to"

Question

The use of the "have to" idiom to denote necessity is interesting when used in combination
with the perfect aspect (i.e., that uses 'have' as an auxiliary verb), as all the 'have'-'s
can get wuite confusing! It seems to be that the first "have", which is the 'have' in the
'have to' idiom, should normally be past non-perfect, as it denotes the state of necessity
as simply being in the past.

"He had to have eaten the pie before dinner for him to have eaten so little at dinner."

However, there is the situation in which the state of necessity must have existed before
some past action, in which case 'have to' idiom must be past perfect.

"He had had to leave to go to school early, before the bus route was established."

However, the necessity of the past action needing to have happened before some other past
action does not use the perfect aspect of "have to"

"He had had to have eaten the pie before dinner for him to have eaten so little at dinner."
<- WRONG

What do you think?

Anonymous · Accepted Answer

The idiom "have to" can be looked at as equivalent to "must." So:

Present: I have to (must) go to the store.
Past: I had to go to the store.
Future: I will have to go to the store.

The above three are the only tenses normally used with "have to." Trying to use it in the present perfect, past perfect, etc. leads to awkward structures.

"He had to have eaten the pie before dinner for him to have eaten so little at dinner." is apparently correct from a purely theoretical grammatical point of view, but it is awkward-sounding and would rarely be used in real life. You'd say instead: "He must have eaten the pie before dinner for him to have eaten so little at dinner."

"He had had to leave to go to school early, before the bus route was established." is not right. You would say "He had to leave early to go to school before the bus route was established."

"He had had to have eaten the pie before dinner for him to have eaten so little at dinner." is not right. You'd say "He must have eaten the pie...."

Fivejedjon · Answer

AnonymousThe above three are the only tenses normally used with "have to." Trying to use it in the present perfect, past perfect, etc. leads to awkward structures.

I agree with some of your points, but I can't agree with those. The following are fairly natural in British English:

I've had to work late every night this week.
I've been putting off talking to Emma about this, but I'll have to get round to it soon.
My ***ing car let me down again this morning. I'm going to have to get a new one.

Also: My wife has the car while her mother's ill, so I'm having to cometo work by bus for a few days.

Anonymous"He had had to leave to go to school early, before the bus route was established." is not right.

Well, it's not wrong.

Swampwiz · Answer

I agree that it does sound a bit awkward, and I guess that an modal color idiom should just not use the perfect aspect, even if itseems that it is warranted.

Anonymous · Answer

I thought about this some more and here are further comments (this is an interesting question because it forces a native speaker to analyze something that is normally instinctive for him):

With the idiom "have to," meaning "must," the following are the forms for the third person singular:

Present: He has to eat the pie - his parents insist that he clean his plate. (This is equivalent to "He must eat the pie.")
Past: He had to eat the pie - his parents insisted that he clean his plate. (No "must" form.)
Future: He will have to eat the pie - his parents will insist that he clean his plate. (No "must form.)

Present perfect: He has to have eaten the pie - there is no one else in the room. (Equivalent to "He must have eaten the pie.")
Past perfect: He had to have eaten the pie - there was no one else in the room. (No "must" form.)
Future perfect: He will have to have eaten the pie - there will be no one else in the room when the pie is eaten. (No "must" form.)

Therefore, your sentence, "He had to have eaten the pie....so little at dinner.", is past perfect.

Your sentence, "He had had to leave to go....was established.", is okay, but it is not a form with the idiom "have to." This is simply the verb "to have" in the past perfect, as in the sentence "He had had a hard time in school since the fifth grade."

Your sentence, "He had had to have eaten the pie...so little at dinner.", incorrect. There is no such grammatical structure as this in English. If you want to use the idiom "have to," it would be "He had to have eaten the pie...so little at dinner." (past perfect). If you want to use the verb "to have," it would be "He had had the pie before dinner, which is why he ate so little at dinner." (past perfect).

Swampwiz · Answer

No, this is not correct. If the "have to" should have a perfect sense, that may not necessarily affect the actual verb. Basically, there is no way to use the perfect sense for "have to". The perfection of the actual verb is only done if that activity is to be described as happening before some other time.

Anonymous · Answer

I've looked into this some more, and here are further comments; this has been a very interesting and challenging topic, because it has forced
me, a native English speaker, to examine structures that I've never thought about before and that are ordinarily instinctive and
automatically known to me.

The idiom "have to" is unusual in conjugation. This is apparently because of its quasi-modal nature (it's equivalent to "must" in
certain tenses). Modals are the most complex part of English grammar, and so it is not surprising that an idiom with a modal character
is complex in conjugation.

Although the idiom "have to" is intransitive, in usage it also appears in situations that are quasi-transitive in nature:

"Transitive":

He has to eat pie. (Equivalent to "He must eat pie.")
He had to eat pie.
He will have to eat pie.

He has to have eaten pie. (Equivalent to "He must have eaten pie.")
He had to have eaten pie.
He will have to eat pie.

In this "transitive" mode you can also say, for the perfect tenses (with a different meaning):

He has had to eat pie.
He had had to eat pie.
He will have had to eat pie.

Intransitive:

He has to leave early. (Equivalent to "He must leave early.")
He had to leave early.
He will have to leave early.

He has had to leave early.
He had had to leave early.
He will have had to leave early.

Here you can also say, for the perfect tenses (with a different meaning):

He has to have left early.
He had to have left early.
He will have to have left early.

So, your sentence, "He had to have eaten the pie before dinner for him to have eaten so little at dinner.", according to the above conjugation
guide, is "transitive" past perfect.

Your sentence, "He had had to leave to go to school early, before the bus route was established.", is actually incorrect. It should be, "He had
had to leave early to go to school, before the bus route was established." This, according to the above conjugation guide, is intransitive
past perfect.

Your sentence, "He had had to have eaten the pie before dinner for him to have eaten so little at dinner.", is incorrect, as it doesn't follow
any of the above "transitive" conjugation patterns. Note that you could say, correctly, but with a different meaning: "He always had had
to eat pie before dinner in his youth, because that was the tradition in his culture. As a result, he would eat little at dinner."

The use of past perfect "have to"

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