I am refereeing an academic paper where the authors constantly use the construct "it is shown that (blah)" immediately followed by a demonstration of (blah). I don't recall seeing this construct used in this way; the demonstration is usually anywhere other than immediately after (another paper, another book, a previous paragraph, whatnot). Is this usage correct? If not, why?

I can't quote the paper, but here is a more concrete made-up example of their construct:

First, it is shown that there is at most one foo in this list. Consider any bar from the first sequence, they all fall into one of the three cases above. Since these three cases lead to the same foo, there is at most one foo in this list.

Next, it is shown that there is at least one foo in this list. Note that odd bars are guaranteed to lead to a foo. Since there is an odd bar in the first sequence, there must be a foo in this list.

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    @Daniel δ: Migrating would be a mistake. This isn't a matter of "creative writing" - it's standard practice in some contexts (esp. academic texts). Mar 16 '12 at 21:20

This usage seems extremely confusing to me. I expect that the authors are trying to avoid any use of "we" in this paper (and so are avoiding the standard phrase in math papers "we now show"), but they are doing so incompetently. I would suggest you recommend that the authors replace all of these instances with a phrase like "it will now be shown" or "it will next be shown".

  • I agree. Taking OP's example, First, it is shown that ... confuses me; I expected something like first, we show that ... in that context. On the other hand, I probably wouldn't bat an eye at it can be shown that.... I'm also curious to know if this is a BrE/AmE difference.
    – aedia λ
    Mar 17 '12 at 2:29
  • I really don't see a problem with the usage, and this NGram has 94K "later it is shown" against only 44K "later it will be shown", and I can't find any indications of a US/UK difference in the usage. Standard academic writing to me - all I can think is there might be an arts/science split within academia. Mar 17 '12 at 2:56

Like other answerers, I'm not a referee for academic papers either. But I see nothing unusual in the usage. Google Books, for example, claims 1,550,000 results for "thus it is shown". As I would expect, there's a fairly high percentage of "academic-looking" texts in the results.

Obviously the word "thus" normally indicates that the showing/exposition was in some preceding text, but even that needn't be the case. Section 1 of a paper could start by saying, for example,

First, we [will] prove that A = B, then prove that B = C. Thus it is shown that A = C, the implications of which will be considered in detail in Section 2.

Clearly, the exposition hasn't even happened yet. I think one reason the usage works in academic texts better than in common parlance is because the subject matter is more in the nature of "universal, eternal truths", making present tense a more natural/neutral choice. Similar to the way academic writing tends to favor the passive voice, and eschew personal pronouns.

In case anyone thinks collocating with "thus" disproportionately includes more cases where the phrase occurs after the expository text, consider these instances of "later, when it is shown", often preceded by words like "will be seen [later...]". The exposition invariably has yet to be given.


It would be necessary to see the entire paper to judge whether or not it's appropriate, but the construction is certainly grammatical and the passive is typical of academic prose.

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    The problem is the tense. This construction is equivalent to saying at a recital "Bach's Fugue in D Minor is played" before the actual performance. You need to say "will now be played". Mar 16 '12 at 19:27
  • Using "it is shown" in an abstract for a paper may be entirely appropriate. As far as a substitute expression I might go for: "As shown below"
    – Jim
    Mar 16 '12 at 21:43
  • Although thinking about it, does this demonstrate an inconsistency in the use of tenses in English? "We next play Bach's Fugue in D Minor" seems perfectly fine in present tense, but "Next, Bach's Fugue in D Minor is played" in present tense sounds really wrong. A similar thing happens with "We show" and "It is shown". Mar 16 '12 at 21:49
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    @PeterShor: The present tense is one of several ways English has of expressing the future. Mar 16 '12 at 21:54
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    @Barrie: but my question is: in passive sentences, can the present tense be used to express the future? For example, "Tomorrow, they show us the factory" is correct. But "Tomorrow, we are shown the factory" sounds utterly wrong to me. Is it just me, or is this a U.K./U.S difference, or can the present tense not be used to express the future in the passive voice? Mar 17 '12 at 1:39

I'm not a referee for academic papers, but my reaction to "It is shown" would be "Where?" -- I think the use of the passive voice implies a certain distance, as you point out. In fact it's not only a physical distance ["you need to look elsewhere"] but a metaphorical distance ["it wasn't us"].

I think I would go for "We can show [whatever] by ..."


Given the example, "It is evident" might be better than "It is shown", because that invites the response "Is it? How?" and it's immediately answered.


With your example, an accompanying PowerPoint came to mind. In this case, I'd say it's just awkward phrasing -- people have natural tendency to slide to passive voice in writing or prepared statements, because unless they know better, active voice feels too dominant, too "in your face".

And that's what this example feels like to me -- especially since your "foo" and "bar" occlusions imply this is a technology or programming presentation.

Now, when someone uses "it has been shown" without referencing where, when, who and what in some way, then it's nothing but pure weasel words. They expect you to take it on face value that it has been shown, that the showing was done properly, and that the conclusion they (the show-ers) and they (the presenter) have come to is correct.

That's either an indication the speaker's not as familiar with the topic as they let on, a sign of arrogance, or they're flat out trying to pull the wool on you.

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