Theories of Word Meaning

Reference

Ask anyone (over 10 years old!) what cup or sponge means and they are apt to respond by pointing to an instance of the object. Referential theories of meaning define the meaning of words or phrases in terms of the things (or actions, qualities, relations, etc.) that the word or phrase denotes. If we ask someone for a cup and they hand us a sponge, we are apt to think they did not understand the word cup. More precisely, we can equate the meaning of a noun with the set of things that are that object.

CUP = the set of things that are cups

SPONGE = the set of things that are sponges

Just to keep things straight, I will put a word in italics when I mention it and will use capital letters to refer to the meaning of a word. So CUP is the meaning of the word cup. A cup is the thing referred to by the English word cup.

Problem 1: Semantic Intension

A referential theory of meaning accounts for our ability to point to the things that words denote, but it has several critical shortcomings. The philosopher Frege pointed out a critical flaw using the phrases morning star and evening star. These phrases have the same referent, but different meanings. Using them in a sentence makes this difference obvious.

The morning star is the morning star.

The morning star is the evening star.

The first of these sentences does not tell us anything new, while the second sentence does. A referential theory of meaning does not predict this difference.

Frege distinguished between a word’s semantic extension and its semantic intension. The semantic extension of a word is the set of things the word denotes, while its semantic intension is the concept or meaning of the word. The meaning of a word determines the things it refers to, but it cannot be equated with its denotations.

Problem 2: Opaque Contexts

Sentence meaning displays a similar distinction between extensional and intentional meanings.

George is the best student in linguistics.

I dreamed that George is the best student in linguistics.

The first sentence asserts that George is one and the same shining paragon of linguistics. In other words, it asserts that George and the best student in linguistics have the same semantic extension.

If George is the best student in linguistics then the first sentence is true. Assuming the first sentence is true, however, does not guarantee the truth of the second sentence. The truth of the second sentence depends on what I dreamed and not on the truth of George being the best student in linguistics. We can usually equate the semantic extension of a sentence with its truth value, but we see that the truth of the embedded clause has no effect on the truth value of the second sentence. We need something more than the semantic extension of the embedded clause to understand the second sentence.