Reference and related notions

Reference and related notions

Reference

The preeminent function of a noun phrase like Bill Clinton, my two cats, the king of France, Santa Claus, or colorless green ideas is to refer---that is, to stand for a particular discourse entity, its referent. As the examples show, referents can be entities in the actual world, entities in some possible world, or even entities that could not possibly exist in principle. One of the characteristic features of human language is the absence, in general, of a one-to-one relation between noun phrases and referents. On the one hand, it is possible to use different noun phrases to refer to the same referent. The classic example for this is the fact that the expressions the morning star and the evening star both have the same referent, the planet Venus (which is not a star at all!). Conversely, the same noun phrase can have different referents. For instance, my apartment, used either by the same person at different points in time or by different persons at the same point in time, can refer to lodgings of vastly different size and attractiveness in completely different locations. Similarly, my checking account balance can refer to widely differing and varying dollar amounts.

In general, then, determining the intended referent of an expression requires recourse to a particular discourse context (who is speaking when, to whom, and so on). The interpretation of certain expressions, however, is particularly context-dependent. The expressions in question are pronouns. For instance, it is perfectly natural to introduce a new topic in a conversation with a friend using (1a) (provided that the speaker and the friend have in common a single acquaintance by the name of Vanessa). But replacing the proper noun Vanessa with a pronoun, as in (1b), in the same context is decidedly odd.

(1) a.   I ran into Vanessa the other day.
b. I ran into her the other day.

On the other hand, if Vanessa has already been mentioned in the discourse, then (1b) is perfectly felicitous, as illustrated in the mini-discourse in (2).

(2)     A: Have you seen Vanessa recently?
B: I ran into her the other day.

Pronouns, then, in contrast to most other noun phrases, are referentially dependent on some antecedent in the discourse.

The term 'antecedent' is potentially misleading. Since it is derived etymologically from Latin ante-cedens 'one who walks before', an antecedent might reasonably be expected to be required to precede a referentially dependent expression. It is important to realize that, contrary to this expectation, precedence is neither a necessary nor a sufficient condition for antecedenthood. In a sentence like (3), for instance, Zelda does not precede she, yet is nevertheless able to serve as the pronoun's antecedent.

(3)     If she calls, tell Zelda that the package arrived.

On the other hand, Zelda precedes her in both examples in (4), but is unable to serve as the antecedent of her in (4b) (the intended meaning of (4b) is 'Zelda likes herself').

(4) a.   Zelda is convinced that nobody likes her.
b.   Zelda likes her.

A less misleading term for the notion of antecedent might be 'referential anchor,' but we continue to use the term 'antecedent' because it is a standard term.

Coreference

A discourse will often contain more than one possible antecedent for a pronoun. For instance, in (5), he can refer to either Tim or Tom.

(5)     Tim told Tom that he needed some time off.

In any particular discourse context, of course, one interpretation may well be favored over the other, given what is known about Tim, Tom, their respective work loads, and so on. In case the antecedent for he must be explicitly specified in an unambiguous way, this can be achieved as in (6).

(6) a.   Tim told Tom that he, Tim, needed some time off.
b.   Tim told Tom that he, Tom, needed some time off.

When (5) is given the interpretation in (6a), he and Tim are said to corefer. On the alternative interpretation in (6b), it is he and Tom that corefer.

Coindexing

It is convenient to introduce a general notational device to represent relations of coreference. Let us begin by asssociating any noun phrase with a referential index. In the literature, it is standard to use the letters of the alphabet as indices, beginning with i (for 'index'). But as we will use i, j, k, ... as indices with another function in later chapters, we adopt the convention throughout the book of using the natural numbers as referential indices. We now introduce the following convention. In order to indicate an interpretation in which two expressions refer to the same discourse entity (in which they corefer, in other words), we assign the same index to both expressions. The two expressions are then said to be coindexed. On the other hand, in order to indicate an interpretation in which two expressions refer to distinct discourse entities (that is, in which they do not corefer), we assign distinct indices to each of the two expressions. Such expressions are said to be contraindexed. In neither case are the specific indices important---only whether the indices are the same or not. That is, both indexings in (7) represent the interpretation in (6a), and both indexings in (8) represent the interpretation in (6b).

(7) a.   Tim1 told Tom2 that he1 needed some time off.
b. Tim1097 told Tom18 that he1097 needed some time off.
(8) a.   Tim1 told Tom2 that he2 needed some time off.
b. Tim380 told Tom7 that he7 needed some time off.

(9) gives a further possible indexing for the sentence in (5). Of course, in any particular discourse, this indexing is felicitous only if a discourse entity with the index 3 (say, Tim's brother Mike) has already been mentioned.

(9)     Tim1 told Tom2 that he3 needed some time off.

Grammatical and ungrammatical index assignments

Take good care to distinguish between reference and indexing. Reference relations are actual linguistic relations that we have intuitions about. For instance, we have the intuition that Tim and him can corefer in (10a), but not in (10b).

(10) a.   Tim thinks that everyone admires him.
b. Tim admires him.

The assignment of indices, on the other hand, is a notational device that is intended to represent arbitrary reference relations; the indices themselves have no independent linguistic or psychological status. As a result, it is perfectly possible to assign referential indices to noun phrases so as to represent interpretations of a sentence that are possible in principle, but impossible in fact. Two such ungrammatical indexings are illustrated in (11).

(11) a. * Tim1 admires him1.
b. * He1 admires Tim1.

Notice that the proposition that both (11a) and (11b) are trying to express is not inherently semantically anomalous. It can be expressed perfectly grammatically as in (12).

(12)     Tim1 admires himself1.

Notice furthermore that what makes these sequences ungrammatical is the index assignment. The same sequences of words as in (11) are grammatical sentences when associated with the indices in (13).

(13) a. ✓ Tim1 admires him2.
b. ✓ He1 admires Tim2.

In other words, the grammaticality of a sequence is always determined with reference to a particular intended interpretation.

Representations like those in (11) and (13) are generally abbreviated as in (14). The descending numerical order of the indices on the object noun phrases is intended to make clear the scope of the asterisk.

(14) a. ✓ Tim1 admires him2,*1.
b. ✓ He1 admires Tim2,*1.

Why can't sentences like (11a) or (11b) express the proposition that is expressed grammatically in (12)? Such questions are what binding theory seeks to answer, the topic of Chapter 14.