A
word, phrase, or sentence is ambiguous if it has more than one meaning. The
word 'light', for example, can mean not very heavy or not very dark. Words like
'light', 'note', 'bear' and 'over' are lexically ambiguous. They induce ambiguity in phrases or sentences
in which they occur, such as 'light suit' and 'The duchess can't bear
children'. However, phrases and sentences can be ambiguous even if none of
their constituents is. The phrase 'porcelain egg container' is structurally ambiguous, as is the sentence 'The police shot the rioters
with guns'. Ambiguity can have both a lexical and a structural basis, as with
sentences like 'I left her behind for you' and 'He saw her duck'.
The
notion of ambiguity has philosophical applications. For example, identifying an
ambiguity can aid in solving a philosophical problem. Suppose one wonders how
two people can have the same idea, say of a unicorn. This can seem puzzling
until one distinguishes 'idea' in the sense of a particular psychological
occurrence, a mental representation, from 'idea' in the sense of an abstract,
shareable concept. On the other hand, gratuitous claims of ambiguity can make
for overly simple solutions. Accordingly, the question arises of how genuine
ambiguities can be distinguished from spurious ones. Part of the answer
consists in identifying phenomena with which ambiguity may be confused, such as
vagueness, unclarity, inexplicitness and indexicality.
1. Types of ambiguity
There are two types of ambiguity, lexical and structural.
Lexical ambiguity is by far the more common. Everyday
examples include nouns like 'chip', 'pen' and 'suit', verbs like 'call', 'draw'
and 'run', and adjectives like 'deep', 'dry' and 'hard'. There are various
tests for ambiguity. One test is having two unrelated antonyms, as with 'hard',
which has both 'soft' and 'easy' as opposites. Another is the conjunction
reduction test. Consider the sentence, 'The tailor pressed one suit in his shop
and one in the municipal court'. Evidence that the word 'suit' (not to mention
'press') is ambiguous is provided by the anomaly of the 'crossed
interpretation' of the sentence, on which 'suit' is used to refer to an article
of clothing and 'one' to a legal action.
The above examples of ambiguity are each a case of one
word with more than one meaning. However, it is not always clear when we have
only one word. The verb 'desert' and the noun 'dessert', which sound the same
but are spelled differently, count as distinct words (they are homonyms). So do
the noun 'bear' and the verb 'bear', even though they not only sound the same
but are spelled the same. These examples may be clear cases of homonymy, but
what about the noun 'respect' and the verb 'respect' or the preposition 'over'
and the adjective 'over'? Are the members of these pairs homonyms or different
forms of the same word? There is no general consensus on how to draw the line
between cases of one ambiguous word and cases of two homonyous words. Perhaps
the difference is ultimately arbitrary.
Sometimes one meaning of a word is derived from another.
For example, the cognitive sense of 'see' seems derived from its visual sense.
The sense of 'weigh' in 'He weighed the package' is derived from its sense in
'The package weighed two pounds'. Similarly, the transitive senses of 'burn',
'fly' and 'walk' are derived from their intransitive senses. Now it could be
argued that in each of these cases the derived sense does not really qualify as
a second meaning of the word but is actually the result of a lexical operation
on the underived sense. This argument is plausible to the extent that the
phenomenon is systematic and general, rather than peculiar to particular words.
Lexical semantics has the task of identifying and characterizing such
systematic phemena. It is also concerned to explain the rich and subtle
semantic behavior of common and highly flexible words like the verbs 'do' and
'put' and the prepositions 'at', 'in' and 'to'. Each of these words has uses
which are so numerous yet so closely related that they are often described as
'polysemous' rather than ambiguous.
Structural ambiguity occurs when a phrase or sentence has
more than one underlying structure, such as the phrases 'Tibetan history
teacher', 'a student of high moral principles' and 'short men and women', and
the sentences 'The girl hit the boy with a book' and 'Visiting relatives can be
boring'. These ambiguities are said to be structural because each such phrase
can be represented in two structurally different ways, e.g., '[Tibetan history]
teacher' and 'Tibetan [history teacher]'. Indeed, the existence of such
ambiguities provides strong evidence for a level of underlying syntactic
structure (see SYNTAX). Consider the structurally ambiguous sentence, 'The
chicken is ready to eat', which could be used to describe either a hungry
chicken or a broiled chicken. It is arguable that the operative reading depends
on whether or not the implicit subject of the infinitive clause 'to eat' is
tied anaphorically to the subject ('the chicken') of the main clause.
it is not always clear when we have a case of structural
ambiguity. Consider, for example, the elliptical sentence, 'Perot knows a
richer man than Trump'. It has two meanings, that Perot knows a man who is
richer than Trump and that Perot knows man who is richer than any man Trump
knows, and is therefore ambiguous. But what about the sentence 'John loves his
mother and so does Bill'? It can be used to say either that John loves John's
mother and Bill loves Bill's mother or that John loves John's mother and Bill
loves John's mother. But is it really ambiguous? One might argue that the
clause 'so does Bill' is unambiguous and may be read unequivocally as saying in
the context that Bill does the same thing that John does, and although there
are two different possibilities for what counts as doing the same thing, these
alternatives are not fixed semantically. Hence the ambiguity is merely apparent
and better described as semantic underdetermination.
Although ambiguity is fundamentally a property of
linguistic expressions, people are also said to be ambiguous on occasion in how
they use language. This can occur if, even when their words are unambiguous,
their words do not make what they mean uniquely determinable. Strictly
speaking, however, ambiguity is a semantic phenomenon, involving linguistic
meaning rather than speaker meaning; 'pragmatic ambiguity' is an oxymoron.
Generally when one uses ambiguous words or sentences, one does not consciously
entertain their unintended meanings, although there is psycholinguistic
evidence that when one hears ambiguous words one momentarily accesses and then
rules out their irrelevant senses. When people use ambiguous language,
generally its ambiguity is not intended. Occasionally, however, ambiguity is
deliberate, as with an utterance of 'I'd like to see more of you' when intended
to be taken in more than one way in the very same context of utterance.
2 Ambiguity contrasted
It is a platitude that what your words convey 'depends on
what you mean'. This suggests that one can mean different things by what one
says, but it says nothing about the variety of ways in which this is possible.
Semantic ambiguity is one such way, but there are others: homonymy, vagueness,
relativity, indexicality, nonliterality, indirection and inexplicitness. All
these other phenomena illustrate something distinct from multiplicity of
linguistic meaning.
An expression is vague if it admits of borderline cases.
Terms like 'bald', 'heavy' and 'old' are obvious examples, and their vagueness
is explained by the fact that they apply to items on fuzzy regions of a scale.
Terms that express cluster concepts, like 'intelligent', 'athletic' and 'just',
are vague because their instances are determined by the application of several
criteria, no one of which is decisive.
Indexical terms, like 'you', 'here' and 'tomorrow', have
fixed meaning but variable reference. For example, the meaning of the word
'tomorrow' does not change from one day to the next, though of course its
reference does.
Nonliterality, indirection and inexplicitness are further ways
in which what a speaker means is not uniquely determined by what his words
mean. They can give rise to unclarity in communication, as might happen with
utterances of 'You're the icing on my cake', 'I wish you could sing longer and
louder', and 'Nothing is on TV tonight'. These are not cases of linguistic
ambiguity but can be confused with it because speakers are often said to be
ambiguous.
Ambiguity