Is there a name for this phenomena with the English copula "to be"?

1a - "My day off is Saturday"
1b - "Saturday is my day off"

2a - "John is a doctor"
2b - *"A doctor is John"

I think I've heard it before but can't remember. Also what are the conditions under which it can occur?

  • I don't have anything to add to the excellent answer below, though I thought I'd link to a useful draft paper by Müller which gives a nice summary of some points in Mikkelsen's dissertaiton.
    – user483
    Commented Oct 20, 2013 at 16:47

1 Answer 1


The difference you've identified is between predicational and specificational copular clauses (terms coined by Higgins, 1979, i think). In a predicational copular sentence, the subject denotes an individual and the complement (which may be either a Noun Phrase, or an Adjectival Phrase) denotes a property. The subject is predicated of the complement. Your examples 1b (i) and 2a (ii) are predicational copular clauses.

(i) [Saturday]<e> is [my day off]<e,t>
The entity denoted by 'Saturday' satisfies the property of being the speaker's day off.

(ii) [John]<e> is [a doctor]<e,t>
The entity denoted by 'John' satisfies the property of being a doctor.

In specificational copular clauses, the relationship between subject and complement is reversed - the subject (which may only be a Noun Phrase, due presumably to the EPP), denotes a property, and the complement denotes an individual, which is predicated of the subject. Your examples 1a (iii) and 2b (iv) are specificational copular clauses:

(iii) [My day off]<e,t> is [Saturday]<e>
The entity denoted by 'Saturday' satisfies the property of being the speaker's day off.

(iv) #[a doctor]<e,t> is [John]<e>
The entity denoted by 'John' satisfies the property of being a doctor.

Note that specificational copular clauses and their predicational counter-parts are truth-conditionally equivalent. The difference is generally considered to be driven by information-structural considerations, such as topic and focus (see Line Mikkelsen's dissertation on the topic). One common assumption is that predicational and specificational copular clauses have the same underlying D-structure, as follows (using X'-notation):

(a) [SpecIP ... [I' [+pres] [VP ... [V' is [predP John [pred' pred [NP a doctor]]]]]]]

The copular takes a small clause complement (a "predP", in Mikkelsen's terminology). The functional head pred takes a specifier of type <e> and a complement of <e,t>. In a predicational copular clause, the individual-denoting element in specPredP raises to the matrix subject position, and the complement remains in situ. In a specificational copular clause, the property-denoting element in compPredP raises to the matrix subject position, and the subject remains in-situ. See Mikkelsen's thesis for further discussion.

EDIT: @Daincihi points out that i don't explain why (iv) is bad in my answer. (v), below, illustrates that there isn't any general ban on indefinite specificational subjects:

(v) [A philosopher who seems to share Kiparskys’ intuitions on some factive predicates] is [Unger] (1972), who argues that ...

I mentioned that under Mikkelsen's account, the difference between a predicational and specificational copular clause concerns information structure. One of the restrictions on a specificational copular clause is that the subject must be a topic (i.e. it must be given/old information). A bare indefinite such as "a doctor" can't function as a topic for fairly obvious pragmatic reasons, whereas an indefinite modified by a relative clause can, hence the difference in acceptability between (v) and (iv).

N.b. I presuppose a very basic knowledge of type-theoretic semantics in my answer.

Some terminology, following @cerberus's suggestion:

e = the semantic type 'individual' (the type of, e.g. a proper name)
t = the semantic type 'truth-value' (the type of a sentence)
<e,t> = a function from individuals to truth-values (i.e. the type of a property, or predicate)

EPP = The Extended Projection Principle; The requirement that all English sentences have a subject.

  • 1
    Perhaps you could define and explain your terms for the benefit of people in other (sub)fields, at least up to the last paragraph, because I have to say I am unfamiliar with most of them, and I'm sure I could follow your argument with a little help. Specifically <e>, <t>, <e,t>, EPP, "information-structural considerations" (I know what you mean, but only because I happen to be familiar with the theories).
    – Cerberus
    Commented Oct 20, 2013 at 15:40
  • Sure, that's a good suggestion - i'll edit my answer when i have a little time. It's often difficult to know at what level to pitch an answer on here, and it's difficult to discuss certain issues without presupposing at least some theoretical machinery. See the link at the end for information about semantic types.
    – P Elliott
    Commented Oct 20, 2013 at 15:42
  • Yes, that is always a complicated matter. I'm sure some people here will understand those terms. I didn't even try understanding your last paragraph; one probably needs to know X-bar theory anyway in order to understand it, so there is little to gain by explaining terms. Thanks for adding those definitions btw, that helps. Perhaps your could also explain "semantic type" and "matrix subject" as opposed to "subject"? Is <e> by chance similar to ∃?
    – Cerberus
    Commented Oct 20, 2013 at 16:07
  • @cerberus By 'matrix subject' i meant highest subject, but i'm not sure it was relevant (or correct actually) to make that distinction here. Have omitted it. <e> is different to ∃. Type theory divides all semantic objects into types - the simplex types are <e> and <t>, all other types are functions built by combining these types. Something that is type <e> is just something that denotes an individual, such as a proper name. Something that is type <t> is something that denotes a truth-value, such as a sentence. It's a somewhat similar idea to category labels in syntax.
    – P Elliott
    Commented Oct 20, 2013 at 16:12
  • @cerberus Just to massively complicate things, ∃ is generally considered to be of type <<e,t>, <<e,t> t>> :-p. Type theory is worth reading up on though, it should be covered in any good intro to formal semantics. It gives you a nice formally explicit way of interpreting syntactic structures.
    – P Elliott
    Commented Oct 20, 2013 at 16:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.