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I've been confused about this as long as I can remember. Should it be:

One should do ones duty.

or

One should do one's duty.

I'm guessing it should be the latter. But that doesn't sit well with the possessive pronoun 'its'. For example:

It is its own purpose.

vs.

It is it's own purpose.

Here, the former seems clearly correct.

herisson
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boehj
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2 Answers2

39

The correct answer is one's!

All possessives get an apostrophe, except the standard possessive pronouns and these are:

yours, his, hers, ours, theirs, its, whose

Apart of these, always add an apostrophe.

Community
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Frantisek
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  • Note also that "ones" is always incorrect, because a noun with an explicit singular meaning should not be pluralized. "Ones" would be similar to "Is" instead of "us," or "yous," "hes," or "shes," instead of "them." – Bacon Bits May 21 '11 at 05:04
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    @Bacon Did you see the frightened ones? (Goodbye Blue Sky) – Phira May 21 '11 at 05:10
  • @user9325 Fair enough. Almost always incorrect. It would have to refer to a multitude of singular objects which are called a "one", which is a somewhat unusual case. Still, I'm not convinced it's not incorrect. "Frightened people" would be more correct. It's not like Roger Waters was an Oxford professor. The only other case I can thing of is when 'one' is the name of the object, i.e., "four ones" for four one-dollar bills. – Bacon Bits May 21 '11 at 05:18
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    @Bacon: And the Great Old Ones are Great Old People, too? :) – Phira May 21 '11 at 05:21
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    @Bacon @user9325 - The Young Ones. – Karl May 21 '11 at 05:37
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    @Bacon It's not so uncommon. Try these: "Son, would you like the purple ones or the blue ones?" "Wow, (pointing at animals) look at the little ones!" Saying "almost always incorrect" is incorrect. – ErikE May 21 '11 at 07:30
  • @Erik @Karl @user9325 I'm going to have to go look this up some more. I've been taught by several teachers that 'ones' as a pronoun is explicitly wrong, but clearly that's not the case. – Bacon Bits May 21 '11 at 19:06
  • It is not logical that "one's" has an apostrophe and "its" does not. They are formed the same way as other possessives, while the others are distinct words. Would plural "ones" possessive be "ones'" then? "The young ones' music"? – endolith May 28 '11 at 15:10
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    @endolith - 1) This is English we're talking about; you expected logic? As stated in the answer, there are six "standard" (by which we mean "irregular") pronouns; apart from those, you should add an apostrophe. Try not to think too hard about why those six are different from all the others - you'll only make yourself old before your time. 2) Yes, "the young ones' music makes me angry and gives me a headache" is correct. – MT_Head Jun 07 '11 at 07:48
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    don't even mention "whose" :( – tenfour Sep 06 '11 at 13:25
6

Indefinite pronouns like one and somebody: one's, somebody's

The possessive of the pronoun one is spelled one's. There are many types of pronouns. Unfortunately, people explaining the mnemonic for remembering the spelling of its sometimes over-simplify and say something like "it doesn't have an apostrophe because it's a pronoun, like his or her". But actually, as already mentioned, there are many pronouns that have possessive forms ending in -'s. The pronoun it belongs to a particular subset of pronouns that have irregular (or at least irregularly spelled) possessive forms.

RiMMER's answer describes yours, his, hers, ours, theirs, its as "standard" possessive pronouns. For some people, it might help to think of this instead in terms of "definite pronouns" and "indefinite pronouns".

The definite pronouns you, he, she, it, we, they have possessive forms that are spelled without an apostrophe even though they end in "s". (Some definite pronouns have possessive forms that don't even end in "s", such as my/mine, her, our, their.)

But the more numerous indefinite pronouns (one, someone, somebody, nobody, another, etc.) take the usual -'s to mark the possessive.

Not all pronouns belong to either of these two categories. As tenfour mentioned in a comment, there's also the interrogative and relative pronoun who which has the irregularly spelled possessive form whose.

How one and one's is different from other indefinite pronouns

The possessive of one (one's) is formed the same way as the possessive of other indefinite pronouns, such as someone (someone's), but it is used a bit differently. For most people, one is consistently used with the possessive form one's. Other indefinite pronouns can (in fact, must) be referenced in some situations with the possessive form of a third-person definite pronoun like his, her or their. Here's an example of what I mean:

  • Someone left his/her/their hat on the table.

  • No one likes to have his/her/their word doubted.

We don't use someone's or no one's in this context (i.e., to refer back to an earlier use of someone or no one in the same sentence). However, many people would say the following sentence:

  • One does not like to have one's word doubted.

—A Dictionary of Modern English Usage, by H. W. Fowler (OUP's "Classic" First Edition)

The linked passage in Fowler mentions that "One does not like to have his word doubted" also existed in his time as a competing form. I don't know to what extent modern writers use his (or perhaps their) in sentences like this, but it's definitely less common than one's.

Another way one is unlike the other indefinite pronouns is that it has a special reflexive form, oneself.

herisson
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