Originally purposed for this ELL question, the following from this thread claims that which I've greyed.
I ask about such a claim for English and French.

[User 'RuthP' dated 2012 Dec 26:]
That is a(n incorrect) hyper-correctness, to which many people are prey. No, because the only verb you have is to be (are, in this case). To be cannot take an object, because it is an identity, so in your sentences, who and we are the same. Since we is the subject, so is who.

Footnote: I'm unversed in linguistics, but I'm self-learning this with A Student's Introduction to English Grammar, 2005, by Rodney Huddleston, Geoffrey Pullum.

  • No, that's not the reason. The reason is that be is always an auxiliary verb, never a main verb. Only main verbs can take objects. Be is the auxiliary for all predicate nouns, all predicate adjectives, all predicate phrases and clauses, the Passive and Continuous constructions, and hundreds of idiomatic constructions. It's as intransitive a verb as there is in English. It is not, however, "an identity". That usage, alas, shows that the author had no notion of what the reason was, but felt obliged to present one anyway. I.e, not correct. Feb 28, 2015 at 18:49
  • 1
    @johnlawlerinexile Not everyone considers "to be" to always be an auxiliary verb; some definitions consider auxiliary verbs to be verbs that add meaning to another verb, with "to be" does not always do. By this definition, "to be" in "He is helping me." is an auxiliary verb, but "to be" in "He is Bob." is not. There is actually a specific word for "to be" words in languages, and that word is copula. In fact, the object form does seem to be proper after a copula in Engish: "I am him" vs. "I am he"
    – Zgialor
    Mar 3, 2015 at 20:02
  • Definitions can be made by anyone. And are. No two definitions of English be -- or for that matter, no two descriptions of any of its uses -- are identical. Definitions are cheap; tests are more useful in the long run. And predicate nouns and adjectives require be as an auxiliary, just as much as the progressive or passive. If you can describe precisely the kind of "meaning added" by it, feel free to do so. But basically it's just word waving. Mar 3, 2015 at 21:50
  • Actually, @johnlawlerinexile, auxiliary verbs can take objects. Possessive have takes as object the thing possessed, yet, at least in British English, it inverts with the subject in questions, showing that it is an auxiliary ("Baa, Baa, black sheep, have you any wool?").
    – Greg Lee
    Mar 7, 2015 at 17:22
  • @Greg: Yes, that's true for have, but only in its possession sense, which is still meaningful (or as meaningful as a possessive can get, I spose) but is treated in American English as a verb requiring do-support in that sense. The other senses of have are farther adapted to auxiliary status. As you know, it's not a black-and-white matter; constructions and words change gradually. My favorite metaphor is an orbits slowly decaying as the gravity of the main verb attracts the auxiliary verbs, until they're tidelocked.
    – jlawler
    May 1, 2015 at 18:39

2 Answers 2


What the writer means with "identity" is that sentences of the type

The thing A is a thing B

(eg: An apple is a fruit. A dog is an animal.)

contain the same idea as in mathematics 2 + 3 = 5.

Sentences with a form of    'to be + subject complement'
totally differ from sentences with transitive verbs (verb + direct object).

I don't think that "identity" is optimal to describe the relation between subject and subject complement. Actually I think a good term is lacking. Even "equality" is not appropriate in all cases. If I say "The child is sick" then I would not say there is an equality between 'child' and 'sick'.

The formulation "to be is an identity" is totally confusing and a "non-information". The traditional term is 'linking verb'. The Latin term is copula meaning ribbon. The verb 'to be' is a mere abstract link between subject and subject complement (a noun, an adjective, an adverb) and has the same function as the sign = in mathematics. And with subject complements 'to be 'is a full verb, and not an auxiliary verb. Auxiliary verbs help to form tenses and similar things.

You can say that the complement after 'to be' gives some information about the subject. We could also say the linking verb 'to be' describes a relationship between subject and subject complement (also called predicative complement).

In a sentence with a transitive verb we have a different situation. A verbal activity goes from the subject over to the direct object. Latin trans-ire is 'over' + 'to go', and 'transitive' means "going over".

Actually a good and easy term for sentences of the type

  • A dog is an animal - The child is sick - He is here -The book is on the table

is lacking. My personal term is simply "is-sentences", defined as a form of 'to be + subject complement'. It is astonishing how many learners wrestle with is-sentences and "transitive" sentences, obviously because grammars neglect this side of language and don't offer appropriate terms for describing language.


The user obviously gets grammar and semantics mixed up. 'be' denotes an identity, so 'who' and 'we' in your question are coreferential, but semantic coreferentiality does not entail being the same kind of syntactic constitutent.

In 'John cut himself', 'John' and 'himself' are also coreferential, but that doesn't make 'himself' a subject (or 'John' an object). So no, identity is not a grammatical term, it's a semantic term.

  • Is identity really the same as coreferentiality? I just googled "is the same as", and the first thing that came up was "Drinking a glass of red wine is the same as getting an hour of exercise". But that doesn't mean the two refer to the same activity.
    – Greg Lee
    Mar 7, 2015 at 17:29
  • I would argue that in that case 'drinking a glass of wine' is neither identical, nor coreferential with 'an hour of exercise'. But no, identity and coreferentiality are not the same thing. Coreferentiality means that two symbols refer to the same entity, whereas identity means that two things are actually only one thing. In your example, I should think that 'is' equates 'drinking a glass of wine' and 'the same as getting an hour of exercise', not 'getting an hour of exercise'; when it's not used with to noun (phrases), it doesn't denote identity but a property of the subject.
    – user9315
    Mar 7, 2015 at 18:32
  • Not only does 'be' usually not denote an identity, I (mis)remember Russell as writing it would be a category error to say that it does. Jul 6, 2015 at 22:13

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