What do the pronouns indicate? [closed]

Whatever one believes about the merits of completing the remaining intercity portion of the system, it is clear that 1) it gives the country an intercity transportation network that would be sorely missed had 2) it not been built. Even those who argue against 3) it 4) do so on the ground that if it had not been built, some better (nonauto) system would have been divised.

Does 1) “it” indicate completing the remaining intercity portion of the system?

Does 2) “it” indicate "the remaining intercity portion"?

Does 3) “it” indicate the same as 1)?

Why does 4) “do so” appear in the present tense and not in the past tense?

And what does “do so” indicate here?

Edit note: HEALTH WARNING & ACTUAL ANSWER

I managed to track down the original text that this extract comes from. It turns out that a bit more context would indeed have made this text very easy to understand. Most importantly, the pronouns 'it' here actually refer to an item mentioned in the previous sentence, not in the given excerpt. In particular, all the Original Poster's 'it's refer to "the interstate highway system". It's a good reminder that a pronoun can be used to refer to something that's been mentioned way back in the discourse. It certainly doesn't need to refer to something in the same sentence! Here's the original - with a tiny bit more context:

Consider the interstate highway system. Whatever one believes about the merits of completing the remaining intracity portion of the system, it is clear that it gives the country an intercity transportation network that would be sorely missed had it not been built. Even those who argue against it do so on the grounds that if it had not been built, some better (nonauto) system would have been divised. Yet most observers would agree that the interstate highway system could not have been built if it had been proposed in the mid-1970s rather than in the mid-1950s.

We can understand the paragraph like this:

Consider the interstate highway system. Whatever one believes about the merits of completing the remaining intracity portion of the system, it is clear that the interstate highway system gives the country an intercity transportation network that would be sorely missed had the interstate highway system not been built. Even those who argue against the interstate highway system do so on the grounds that if the interstate highway system had not been built, some better (nonauto) system would have been divised. Yet most observers would agree that the interstate highway system could not have been built if it had been proposed in the mid-1970s rather than in the mid-1950s.

Do so

The reason that do so is present tense is because like its antecedent, argue against it, it refers to people who currently argue that the interstate highway system was a mistake

Refs: Lester Thurow, 1980, The zero-sum society. New York; Basic Books.

Edit note: I was going to leave my wrong and long answer here for readers. However, I thought this might just waste readers' time in the end. If you want to read it for giggles you can have a look in the edit notes!

The answer below the dashed line is my response to the question as originally framed, without the crucial opening sentence of the quoted paragraph included—namely,

Consider the interstate highway system. ...

That sentence changes the frame of reference of everything that follows in the same paragraph. As Araucaria (who uncovered the missing sentence) observes, it provides the referent for all of the referential its that I discuss in my answer (it 1 through it 4). I hate to delete my answer, since it involved so much careful exegesis, but it's now obsolete. I endorse Araucaria's revised answer.

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OBSOLETE ANSWER BEGINS HERE...

Executive summary: Answers to the poster's five questions

To spare you the blow-by-blow discussion that follows this summary, let me answer the author's five questions here as succinctly as possible.

Does 1) “it” indicate completing the remaining intercity portion of the system?

Yes, I think that's what the author intends for it 1 to refer to.

Does 2) “it” indicate "the remaining intercity portion"?

Again, yes. The identity of it 2 in the excerpt follows logically from the identity of it 1, and I think you have identified both of them correctly.

Does 3) “it” indicate the same as 1)?

No, I don't think so. In fact, I don't think that the author clearly identifies the referent for it 3 anywhere in the excerpt. However, I do think that the author has a definite referent in mind, which I would express as "the system that was built" or, more simply, "the resulting system."

Why does 4) “do so” appear in the present tense and not in the past tense?

The present tense is correct here because "do so" refers to "argue against," which appears earlier in the same sentence, and "argue against" is in present tense.

And what does “do so” indicate here?

As I just said, "do so" = "argue against," so the sense of "Even those who argue against it do so on the ground that XXXXXX" amounts to saying "Even those who argue against it argue against it on the ground that XXXXXX." You can see why the author chose an alternative to repeating the phrase "argue against it."

The blow-by-blow discussion

Paragraphs like this one are copyediting heaven (in the gnostic sense) because they offer so many complications that call either for a yellow rain of Post-it flags seeking clarification or for a bold attempt to hammer out a consistently and unambiguously expressed version that represents the copy editor's best guess at what the author meant, accompanied by the innocuous query "Edits ok?"

For convenience, let me reproduce the original excerpt here as given above, except with a couple of amendments: a 0 (zero) marker attached to the first instance of it in the paragraph, and the 4 marker moved to the fifth occurrence of it in the passage. Here's the slightly altered excerpt:

Whatever one believes about the merits of completing the remaining intercity portion of the system, (0) it is clear that (1) it gives the country an intercity transportation network that would be sorely missed had (2) it not been built. Even those who argue against (3) it do so on the ground that if (4) it had not been built, some better (nonauto) system would have been divised.

I note in passing that the two quoted sentences contain five instances of it, and that all five occur within the space of 36 words. That’s a lot of its to juggle, quite aside from the other pronouns that lurk in the passage (and that John Lawler identifies in his answer).

Before we focus on the five its, let’s dispose of the OP's questions about “do so” in the clause “Even those who argue against it do so on the ground that XXXX.” Here, do so simply means “argue against it.” Swapping "do so" out of the sentence in favor of its referent gives us this:

Even those who argue against it argue against it on the ground that XXXX.

Clearly the whole point of using "do so" is to avoid the awkward repetition of the elements stated a moment earlier in the sentence. Now, on to the its.

As John Lawler’s answer observes, the first it (the one marked 0) is a dummy pronoun; writers and speakers use such pronouns all the time, and readers and hearers generally recognize them for what they are instantly, with no slowdown in comprehension. Esthetically, a writer might want to avoid introducing a gratuitous it just prior to the more complicated handful of its that are about to appear—but that consideration isn’t a matter of coherence.

Things get stickier with the second it (the one marked 1). This it is clearly a referential pronoun, but the referent is less obvious. Arguably, it 1 might refer to any of three suspects: (a) "the remaining intercity portion of the system"; (b) "the system"; or (c) "completing the remaining intercity portion of the system." In the past I have encountered similarly structured sentences in which different authors have sometimes meant (a), sometimes meant (b), and sometimes meant (c).

To identify which one this author has in mind, you have to look at the context of the excerpt. Significantly the author asserts that it 1 "gives the country an intercity transportation network"; the use of the simple present gives strongly suggests that the remaining intercity portion of the system has in fact been completed, since the nation wouldn't have an intercity network if parts of the intercity portion remained unbuilt. This in turn supports the idea that it 1 refers to (c) "completing the remaining intercity portion of the system," since the completion of the system is what yields the result that the author talks about immediately afterward.

It 2, in contrast, cannot refer to "completing" because that pronoun appears in the midst of the wording "had it not been built." The phrase "had completing the remaining intercity portion not been built" fails syntactically, so it 2 must refer either to (a) "the remaining intercity portion of the system" or to (b) "the system." Since it 1 focused (in my reading) on (c)—"completing" the unbuilt portions—it follows that it 2 likewise refers to those portions. Hence it 2 refers to (a) "the remaining intercity portion of the system."

The ringer here is it 3. At first glance, it seems eminently reasonable to suppose (as the poster does) that the it in the phrase "Even those who argue against it" refers to (c) "completing the remaining intercity portion of the system." But that choice doesn't make sense given that (as we've seen) the system has already been completed. Nor does it work in the context of the latter two-thirds of the sentence where it 3 appears. Specifically, if we accept that it 4 ("if it had not been built") refers to (b) "the [entire] system"—as it seemingly must if we are to take seriously the proposition that “some better (nonauto) system would have been d[e]vised” to replace it 4—then we face an unexpected logical difficulty: If someone is opposed to building the whole system, they can’t be arguing against merely (c) completing it nor (a) the remaining portions viewed in isolation. That leaves (b) "the system" as the last referent standing, to serve as the referent for it 3 as well.

But are we really going to skip across the previous 27 words to excavate a phrase ("the system") that wasn't the focus of either of the previous two referential its, and anoint it as the referent for it 3? Can we expect any reader to do that? Does it even make sense, once we’ve done it? I don’t think so. A more likely candidate to be the referent that it 3 means to point to (I think) is one that appears nowhere in the extract and differs subtly from "the system"—namely, (d) "the system that was built." Too bad those words don't appear in the excerpt so that it 3 could actually point to them.

Let’s look at the extract with the full-length referents swapped in for their corresponding its:

Whatever one believes about the merits of completing the remaining intercity portion of the system, it is clear that completing the remaining intercity portion of the system gives the country an intercity transportation network that would be sorely missed had the remaining intercity portion of the system not been built. Even those who argue against the system that was built do so on the ground that if that system had not been built, some better (nonauto) system would have been d[e]vised.

This, I think, is the intended meaning of the excerpt. But now that we can see the author’s argument more clearly, we can also see the pointless wheel-spinning of the opening phrase "Whatever one believes about the merits of completing the remaining intercity portion of the system." In my view, the author would be much better served by dropping that entire opening clause and starting at the dummy it (it 0), and using the old referents (slightly modified) to replace it 1 through it 3:

It is clear that completing the remaining intercity portion of the system gives the country an intercity transportation network that would be sorely missed had the last portion of the system not been built. Even those who argue against the resulting system do so on the ground that if it had not been built, some better (nonauto) system would have been d[e]vised.

In this revised version of the excerpt, the old it 4 now refers to "the resulting system," while the other three referential its have been supplanted by their actual referents. The only further simple improvements that I would make to the edited excerpt would be to drop the wooden "It is clear that" introductory phrase, to identify "those" a bit more sharply as "critics," and to spell devised correctly. Those changes would yield this wording:

Completing the remaining intercity portion of the system gives the country an intercity transportation network that would be sorely missed had the last portion of the system not been built. Even critics who argue against the resulting system do so on the ground that if it had not been built, some better (nonauto) system would have been devised.

Surprisingly, after making clear what all of the original its refer to—and replacing three of them with their actual referents—we end up with an excerpt that is five words shorter than the original.

There are a lot more pronouns than you think here, some denoting, others not:

Whatever (indefinite interrogative pronoun, object of believe)

one (indefinite singular pronoun, subject of believe)
believes about the merits of completing the remaining intercity portion of the system,

it (dummy non-referential pronoun inserted by Extraposition, subject of is clear)
is clear that

it (referential pronoun denoting the system, subject of gives)
gives the country an intercity transportation network

that (relative pronoun denoting network, subject of would)
would be sorely missed, had

it (referential pronoun denoting network, subject of had)
not been built. Even

those (plural distal demonstrative pronoun, used indefinitely)

who (relative pronoun denoting those)
argue against

it (referential pronoun denoting network, object of argue against)
do so on the grounds that if

it (referential pronoun denoting network, subject of had)
had not been built, some better (nonauto) system would have been devised.

And this doesn't exhaust the repertory of types of English pronouns. We use'em a lot.