A. The crucial difference between reference and modification is as follows:
Reference is a relation between a linguistic expression and
a nonlinguistic entity. A referring expression is a pointer
to some nonlinguistic entity.
Modification is a relation between two linguistic
expressions. The modifying expression (= modifier) adds information to
the information associated with the modified expression.
B. If modifiers pick out a (not necessarily proper) subset of the set
denoted by the phrase they modify, then an adjective phrase in predicate
position is not a modifier, as in:
Along with adjectives, prehead nouns in compound nouns are also modifiers, as in:
Of course, modifiers can also be multi-word phrases, which may be adjective
phrases, but need not be:
- In the simplest case of reference, the linguistic
expression is a noun phrase (the door), and the nonlinguistic entity
refers to a concrete entity. In less simple cases, the linguistic
expression is a noun phrase (Chomsky's contribution;
nonviolence; colorless green ideas), and the nonlinguistic
entity is abstract or even nonexistent. Finally, it's possible for
syntactic categories that are not noun phrases to refer. For instance,
adjective phrases (happy to be here, suspicious) refer to
- It is important to recognize that modifiers both modify and
refer. For instance, in the noun phrase a very big house, the
modifier very big modifies house (or a house,
if you want; the difference isn't crucial for our purposes). The
expression very big also refers - to a physical property.
- Because modifiers add information to the information associated
with a modified expression, modification has effects on reference.
In the core case, the reference of a modified expression is more restricted than
that of the original, unmodified expression. For instance, the linguistic
expression students refers (roughly speaking) to a set of people
engaged in a particular activity. When we modify this linguistic
expression by another linguistic expression, say at Penn, the
resulting expression students at Penn refers to a subset of the original
set of students.
- Be sure not to confuse reference with coreference. Here's a
question to consider: Is coreference a relation between linguistic
expressions and entities, or a relation between linguistic expressions?
- very cheerful attitude - adjective phrase modifier
- small craft advisory - noun phrase modifier
- senator from Kansas - prepositional phrase modifier