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Reminded by What is the grammatical function of so in this sentence, something that has always bothered me is that the word "so" can be used as a pronoun:

It looks like rain

Responding with:

No, I don't think so.

(Where "so" refers to the statement about rain "that it looks like rain".)

Definition of 'so' - see items 21, 22, where they say it is a pronoun:


  • such as has been stated: to be good and stay so.

  • something that is about or near the persons or things in question, as in number or amount: Of the original twelve, five or so remain.

Rather, I am not bothered that it might function as a pronoun (weird things happen). I am perfectly fine with it being a pronoun and using it...so. But it never seems to be mentioned in a list of pronouns (as much as memory can serve). It is not in the set of canonical pronouns. "Thus" seems to share this use.

So...(clears throat), what is the provenance and history of this usage? Do other languages have a similar use of a word that introduces a deduction as also a pronoun for a sentence? (And are there any other such non-canonical pronouns?)

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The title makes me imagine a playground argument: “Is not a pronoun!” “Is so a pronoun!” –  PLL Apr 4 '11 at 18:26

4 Answers 4

up vote 8 down vote accepted

The Cambridge Grammar of the English Language has three pages on anaphoric so. It concludes:

...its properties are unquestionably unique, and we do not believe that anything is gained by forcing it into one or more of our general part-of-speech categories.

Consider that so can stand for a noun (We are doctors. So are they.), an adjective (I’m sleepy. So is she.), a verb (Mine broke. So did hers.), a content clause (I thought that salamanders were amphibians. She thought so too.), a whole sentence or idea (The best things in life are free. I’ve always said so.) etc. Yet it can’t be the subject of a sentence. (In So am I, subject-verb agreement shows that I is subject, not so.)

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Nice. That seems definitively unsettled. 'Such' seems to act similarly (doesn't seem to be able to be a subject). Didn't we all already know that the classical part-of-speech categories are somewhat limited? –  Mitch Apr 6 '11 at 13:42
So is a pro-form, if not always a pro-Noun; that much is clear. As such, it has interesting alternations with such and as, among other little words. I would probably think of it as a pro-Quantifier, substituting most often for a particular variety of phrase. Lakoff and Ross have a famous paper from the late '60's, called "Why you can't do so into the sink". In James D. McCawley (ed) 1976. Notes from the Linguistic Underground, Syntax and Semantics, V.7, pp 101-111. Academic Press, New York. –  John Lawler Nov 10 '12 at 22:27

In sentences like "I think so", so is an adverb.

This is not surprising if you think that the word yes is also an adverb.

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Yes - so is just a modifier for think here, where it means thus, or in that fashion. –  FumbleFingers Apr 4 '11 at 14:24
@FumbleFingers, @Robusto: Sure, I think it is as adverbial, but, AHD says that it is a pronoun under certain circumstances. Maybe my example is wrong. I added a link in my question. –  Mitch Apr 4 '11 at 14:28
I think AHD is wrong in this (certainly in "five or so", since if "so" is a pronoun, so is "thereabouts", which would be distinctly odd). In a larger sense, the question shows how the traditional classification of parts of speech is not necessarily adequate. I can accept "so" as an adverb, but calling "yes" an adverb is a nonsense occasioned by the lack of anywhere else to put it among the traditional categories. –  Colin Fine Apr 4 '11 at 14:40
@Mitch: I just followed the link. I'm no expert at formal naming of parts of speech, but I must say that in the first example for so as a pronoun, it looks pretty much like an adverb to me (in be good and stay so it modifies the verb stay). In the second (of 12, 5 or so remain) it looks like an adjective modifying the scalar value of the preceding number. –  FumbleFingers Apr 4 '11 at 14:43
So is an adverb, you can even find the Dictionary entry with the same example "I don't think so"... –  Alenanno Apr 4 '11 at 20:24

No. "So" is never a pronoun in English. In the case you cite it is an adverb, modifying "think".

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I'm not so sure. 'So' is usually an adverb (modifying adjectives). But what about 'I don't think that.' - is 'that' an adverb here? Note that a verb phrase can have two parts, the verb part (with modifiers like adverbs directly modifying the verb) and a noun phrase part (a direct object, a relative clause for example). –  Mitch Apr 4 '11 at 15:34
@Mitch: In that case, "that" is a demonstrative pronoun. It is the direct object of the sentence. –  Robusto Apr 4 '11 at 15:42
Then do you think 'so' and 'that' are or are not functioning the same? I think they are. –  Mitch Apr 4 '11 at 16:39
No, I don't think so. I think "think so" is saying "think [in such a way]" while "think that" is saying "think [a particular thing]". –  Robusto Apr 4 '11 at 16:46
Such is definitely a pronoun. I suppose you could argue that so may be directly replaced by such but that is not true in all cases. In the case of a sentence like "I am your friend and will remain so through thick and thin," although some dictionaries would cite that as a pronominal usage, I still feel that so is really an adverb modifying remain. I could be wrong, but if so is a pronoun there it is a special kind of pronoun and there is at least some ambiguity as to what part of speech it is. –  Robusto Apr 4 '11 at 18:15

I believe it is a demonstrative pronoun. See here and here. (Of course, the internet has much more to offer than that, as you should know.)

In these cases, the specific referent must be mentioned previously in the text for 'so' to work in such a way. 'This' and 'that', among other demonstrative pronouns, work in a similar way as well.

Feel free to correct me if I'm wrong since I've only been a student of linguistics for about a year and a half now.

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I agree that 'so' is working like 'that' in these instances, but I can't find any external confirmation (other than AHD). –  Mitch Apr 4 '11 at 15:29

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