I have learned that "if" is used for more or less likely possibilities while "when" is used for things which are considered facts.

Now I read a bit similar to the following in a book.

My sister had stolen my beer. Last time, my brother had taken it, and I would have expected this to be the case now, too. If it was my sister who took it it was because of the bad example my brother had set.

It has been made clear by the text before that my sister has taken the beer, so there is nothing "if" about this part, as far as I can tell.

  • Is it common to use "if" that way?
  • Is there a name for it/or what it does here?


The original sentence was in a history book and the "if" introduced a historical fact. Unfortunately I can't seem to find it anymore which is why I came up with this rather mundane example. But I do know for a fact that my sister took it.

  • 1
    This is nothing more than 'If it rains we get wet', or 'When it snows we make snowmen'. I don't quite see what distinguishes this 'if' and 'when' from other uses, except that they appear at the start of sentences. I might equally say 'I get wet if it rains'. – WS2 Mar 21 '14 at 10:07
  • "If it was my sister to take it" does not look correct to me. "If it was my sister who took it" sounds better. An interesting if construct could be "If the beer was my sister's to take, she would" – mplungjan Mar 21 '14 at 10:42
  • Just for curiosity... why is there a downvote here? It seems like you get at least one by default, just for asking something. – Emanuel Mar 21 '14 at 11:13
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    There's no special meaning of 'if' here. It is being used somewhat figuratively. Yes, the fact has been established, but then there is an explanation on those cases where the sister has done it. 'In the case that my sister has stolen it, [here is the explanation]'. 'If' always means 'I don't know', but it can be used to imply that 'if I hadn't known'. – Mitch Mar 21 '14 at 12:14

I'm going to disagree with some of the previous posters and say that I think there's nothing ungrammatical here. In constructions such as "If X, then Y" (or simply "If X, Y") the purpose of "If" is not (necessarily) to cast doubt on or express uncertainty of the truth of X, but to express a particular logical relationship between facts X and Y. In your particular example it's illustrating a deductive step from "my sister took it" to "it was because of the bad example my brother set". Here you could replace "if" with something like "given or granted that".

For what it's worth, the OED has this to say about "if":

  1. With the conditional clause or protasis in the indicative. The indicative after if implies that the speaker expresses no adverse opinion as to the truth of the statement in the clause; it is consistent with his acceptance of it.
  2. With the conditional clause or protasis in the subjunctive, and the principal clause or apodosis in the indicative or imperative. The subjunctive after if implies that the speaker guards himself from endorsing the truth or realization of the statement; it is consistent with his doubt of it.

Indicative and subjunctive are verb moods; a tricky subject that you can read more about here. Your example ("If it was my sister...") is in the indicative; if the sentence had read "If it were my sister..." that would be in the subjunctive mood and thus indicate doubt as to the proposition. Verb moods are often poorly understood even among good writers, so you should not rely too heavily on this distinction, but it may still be useful to know.

  • With the exception that in British English, we also use was for the subjunctive. – Matt E. Эллен Mar 21 '14 at 12:50

It's strictly wrong to use "if" to describe a condition that has already been established, but it is seen often enough that the term "common usage" has conferred a kind of correctness on it. So you might see it (as you did) even in a history book. I wouldn't be surprised to read something like "If Caesar crossed the Rubicon in violation of the law, he must have done so out of sheer desperation." He did cross it; that's a fact.

Edit: On second thoughts, you could even say it's correct if you regard the "if" that starts the sentence as a signal that you are putting previously-established facts into suspension for the duration of the sentence, and then proceeding as though discussing a hypothetical case. Then in the next sentence you resurrect the "fact": "The reasons Caesar gave were specious..."

  • Yeah, that is a very good example, in fact. It was something like that and it was by a British writer from the 80s... so you'd say it is not "fancy English" but rather "colloquial English"? – Emanuel Mar 21 '14 at 13:06
  • @Emanuel No, it's not fancy English. It's used in everyday speech by people of only moderate education, or even of no education. Perfectly colloquial. – Terpsichore Mar 21 '14 at 14:09

Analysed from a pure grammar perspective you are correct - the if is not necessary and indeed adds uncertainty to the excerpt quoted. If it was not certain that the sister stole the beer, e.g.

I believe my sister stole the beer. ..... If it was my sister who took it ....

then the if makes sense.

Sometimes authors use devices such as this to enrich the text. It does not make complete logical sense unless the writer meant that the brother was certain it was the sister stole the beer but then thinking about it he had some doubt.

The sentence If it was my sister ... conveys a subtle uncertainty. He knew it was the sister, but then thinking about it he wasn't absolutely sure.

  • The original sentence was form a history book (I can't find it, hence the example) and the "if" introduced a historic fact along the lines of "there was a prolonged up-cry"... so there is no uncertainty in it whatsoever. AT least I can't see it. – Emanuel Mar 21 '14 at 11:10

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