Charles Davis Nov 6, 2012:

@ Tony Your point is well taken; I completely agree. I have seen some of the other questions, and the source text is indeed badly written. In general terms, moreover, I think your caveat is very important. It's a bit like telling the doctor all your symptoms if you want an accurate diagnosis and an effective cure!

Tony M Nov 6, 2012:

@ Charles I agree to some extent with your earlier comment, that the non-restriuctive use of which is likely here —however, I should like to sound a note of caution, inasmuch as the source document Asker is working with here, as seen from earlier questions in this series, is very clearly quite badly flawed EN in places, and so it may well be that the writer was misusing 'which' in the first place; hence why I feel it is so important to get to the bottom of what the actual intended meaning might have been...

Jenni Lukac (X) Nov 6, 2012:

The only downside of this forum is the speed at which we churn out our answers and comments. That said, I love it. It's a pleasure to exchange ideas with such a wonderful group of professionals.

Charles Davis Nov 6, 2012:

Thanks, Jenni :) It's terribly easy to get these things confused!

Jenni Lukac (X) Nov 6, 2012:

I noted that, but I was on the phone when I saw it and couldn't post an entry. I knew that you had intended it the other way around. As it stands now, it's a great explanation.

Charles Davis Nov 6, 2012:

Sorry; I made a mistake in the preceding post, which I have now corrected: I meant to say that a non-restrictive clause (with "which") is preceded by a comma; a restrictive clause (normally with "that") is not preceded by a comma.

As far as I can see, despite the uncertainties, it seems pretty clear that the relative clause here, "which is not given", is non-restrictive and should therefore be preceded by a comma. But I think it would be better to rephrase it, as Jack suggests.

Charles Davis Nov 6, 2012:

which vs. that Both "which" and "that" introduce subordinate clauses (specifically relative clauses). In "The car that I saw was red", "that I saw" is a relative clause. The difference is that "that" introduces a restrictive relative clause, whereas "which" usually introduces a non-restrictive relative clause.

"Restrictive" means that the clause indicates which X out of all possible Xs the speaker is referring to. "The car that I saw was red", as opposed to all the cars that I didn't see, which may not have been red. So it restricts the field of reference of the preceding noun. "Non-restrictive" means that the following clause gives us extra information about the noun. In "The car, which I saw but could not hear, was red", the clause gives us information about the red car: the speaker saw it but could not hear it.

A non-restrictive clause is preceded by a comma; a restrictive clause is not preceded by a comma.

This distinction in the use of "which" and "that" is not always observed; in particular, "which" often introduces a restrictive clause. However, "that" is not used before a non-restrictive clause.

You may find this useful:
http://oxforddictionaries.com/words/that-or-which

Jenni Lukac (X) Nov 6, 2012:

Tony is correct. To be sure that David and I are correct about the second comma, we need to know what follows in order to know whether the choice of which is correct. It's an issue not included in the question posted, but a valid one.

Tony M Nov 6, 2012:

Context It actually all depends on the exact context and intended meaning. IMHO, you have not given us enough context to be sure.

Usually, 'which' introduces a non-restrictive subordinate (relative) clause, and so we expect to find a comma before it. However, there is a tendency, particularly in US EN, to use 'which' to replace 'that', and since 'that' introduces a restrictive relative clause, and is not preceded by a comma, we can sometimes find 'which' correctly used without a comma.

The car that I saw was red
The car, which I saw but could not hear, was red

The problem here is that we don't have enough context to know what was actually intended, and it could be either. In any case, in all these texts you have been posting, the EN is so bad, there's no way of telling what the author was really trying to say.

(Thanks, Charles, for your corrections!)