Being a non native speaker, I cannot spot the difference here:
The only thing that comes to my mind is that in the first case, there is the past infinitive which would imply that it requires him to have been there (before something), while in the second case it requires him to be there at that moment.
"He would have had to have been there" means that, in order for him to have accomplished whatever he accomplished, it would have been necessary for him both to be there and then to leave. In other words, whatever he was supposed to have done could not have been accomplished only by him being there.
Most commonly, however, the action done at the place is simply done at the place, and leaving the place is not required to perform the action. Therefore, we usually say something like, "For him to do what he did, he would have had to BE at that place," because merely being there is adequate to the task. Leaving the place has nothing to do with what he did while he was there.
A quick example: "For Watson to have murdered Lestrade, he would have had to be at Lestrade's apartment." This says it was necessary for Watson to be at Lestrade's apartment (given that the murder occurred in the apartment), but accomplishing the murder did not in some way require Watson BOTH to be there AND to leave.
Now, "have been there" is also logically quite possible. Let's say Sherlock determines that although Lestrade was murdered in Piccadilly Circus, the murderer couldn't have done it unless he had previously been at Lestrade's apartment to see Lestrade's calendar and thereby to know when Lestrade would be found at Piccadilly. In which case, for Watson to have murdered Lestrade, he would have had to have been at Lestrade's apartment beforehand; in other words, Watson would have had to be at Lestrade's apartment and also to leave the apartment (to go to Piccadilly to commit the murder).
Now, all this having been said, we don't usually construct the sentence as elaborately as in the first example ("would have had to have been"). It is not necessary to put the main verb into the conditional present perfect ("would have had"). We usually say simply, "would have to have been."
These sentences do have different meanings though the second one is less likely given the absence of a specific context.
(1) He would have had to have been there [(in order) to have done something].
John, the choice of tense does NOT imply that he can't still be there, although you wouldn't say this if you and your interlocutor both knew that he was still there. The implication is that you didn't know that he had gone there, but now you have evidence that implies that he was there at some point (and indeed may still be there - perhaps you are detectives trying to find him).
(2) He would have had to be there [(in order) to do something].
This sentence sounds stilted out of context and would be quite rare. B Geek gives some examples of the kind of context that would enable this. For example it creates immediacy, by removing a layer of pastness: we've just got off the phone and then are wondering where he was calling from - could he already be in Tel Aviv?
[Before he could leave]: He would have to be there [since he couldn't ring from anywhere else]
[He has probably left but]: He would have had to be there [at the time of the phonecall]
[He has passed that point so]: He would have had to have been there [at some unspecified point]
Note that I have emphasised occurences of hafta or hadta that have the sense of must. This is a complicating factor in this sentence. These are marked by tone, stress and devoicing and don't sound exactly the same as the possessive or auxiliary have/had:
A list of things I have to do during my holidays.
Devoiced reading 1 (must: e.g. work will never let go of me even when I am on holidays...)
Devoiced reading 2 (must: e.g. a list of the places I want to go and see before I die...)
Voiced reading (possess: always bored during the holidays but gran gave me this great list...)
"He would have had to have been there." - This is what you would say if, for example, you were telling about something funny that happened to you earlier and someone listening didn't find it funny- "He would have had to have been there; it's really not as funny without the image of what his face looked like..."
"He would have had to be there." - It is my opinion that this is confusing because it is simply incorrect- you cannot go mixing past and present like that. Either "He has to be there." or "He had to be there." Either "He would be there." or "He would have been there." Either "He would have had to have been there." or "He will have had to have been there."
The proper way to write what I think you mean to say with "He would have had to be there." would be "He would have had to HAVE BEEN there." I imagine that the "have" is left out sometimes in every day usage out of laziness but if "been" is "be" it's not right.
As always, what I am saying is my understanding of the language and could quite possibly be directly at odds with what the rules say, so please correct me if I am wrong.
Your hunch is correct. That “would have had to have been” sequence just makes it seem more confusing than it is. We can reduce the complexity a bit here to make it easier to understand. Instead of:
You just want to look at the parts that differ, so:
The first, perfect version means that the “being there” was already completed sometime previous to some other point. It’s just like this:
Don’t let all the extra words confuse things.
I think in actual practice, people don’t really distinguish these two:
There are two techniques of analyses to make here
A subjunctive mood is expressed in one of the following patterns:
Let us factorize the sentences:
He would have { had { to have {been there} } }.
vs
He would have { had { to be there } }.
Let us simplify the above by looking at the outermost possessive layer.
He would have { complex/simple possessable entity }.
For example,
The construct of the outermost possessive layer is subjunctive. Let us conjure an optative atmosphere to illustrate:
Samy is not here. If he were here, he would have {a friend}.
If Samy were here, he would bring a friend with him.
Let us peel into the 2nd layer:
Samy is not here. If he were here, he would have {had {a friend}}.
If Samy were here, he would have experienced having had a friend, but I am not sure if he still has a friend.
Let us analyse the actual sentences by injecting a reason.
Let us analyse the 1st layer again:
Samy is a liar. He says he has been to Israel. If he has, he would have
{been to Tel Aviv}.
Epiphany 0:
Samy is thinking of going to Israel.
If he goes, he would have
{the need to land in Tel Aviv}.
He would have {to be in Tel Aviv}.
Epiphany 1:
Samy is a liar. He says he went to Israel.
If he did, he would have
{had {the need to land in Tel Aviv}}.
He would have{had {to be in Tel Aviv} }.
Epiphany 2:
Now, analyse the 3rd layer:
Samy is a liar. He says he had been to Israel before I went with him last month. If he had been to Israel before our trip together he would
have{had { to have {been to Ben Gurion} } }
But when I asked him, while the plane was landing, he had no idea what Ben Gurion is.
Answer:
Therefore, the difference is between epiphanies 1 & 2:
Subjunctivity Analysis
To satisfy tchrist's inquiry ...
Present subjunctive:
He would have a friend.
Past subjunctive:
He would have had a friend.
Past subjunctive:
He would have had to be there.
Bayesian-styled past perfect predicate subjected to a past subjunctive uncertainty:
He would have had to have been a friend.
He would have had to have been there.
Present perfect predicate being a subjunctive wish subjected to a past subjunctive uncertainty:
He would have had the wish of having had been there.
Past perfect predicate subjected to a past subjunctive wish which is subjected to another past subjunctive uncertainty:
He would have had the wish where he would have had to have been a there.
Bayesian probability explanation:
Event B can happen if and only if event A happens. What is the cumulative chance of Event B happening at all, given that
Given the following cascading of events, the next occurring only if the previous had occurred, what is the cumulative chance of Event En+1 occurring?
Example of Bayesian-style cascaded/hierarchical subjunctivity:
He would have had to have been having to have the privilege to have been experiencing the shock of having had the encounter against an adversary who might have had been having had the worst form of defence ever.
He would have had to have been there.
He had to possibly be there before % [%= the past events on mind]
He would have to have been there.
He had to possibly be there before % [%= the events on mind]
He would have had to be there.
He had to possibly be there before now [no need of other events on mind]
He would have had to been there.
Incorrect English.
