A proper name [is] a word which answers the purpose of showing what thing it is that we are talking about" writes Mill in A System of Logic (1. ii. 5.), "but not of telling anything about it". The problem of defining proper names, and of explaining their meaning, is one of the most recalcitrant in modern philosophy.

Table of contents
1 The Problem of Proper Names
2 Theories of Proper Names

The Problem of Proper Names

Mill's definition is as good as any, though it is ultimately not helpful. A proper name tells us *which* thing is in question, without giving us any other information about it. But how does it do this? What exactly is the nature of this information? There are two puzzles in particular:

(i) The name in some way reveals the identity of the object. An identity statement, such as "Hesperus = Phosphorus" should contain no information at all. If we understand the names, we should understand the information they carry, namely the identity of their bearers, and if we grasp their identity, we should understand automatically whether the statement is true or false. Thus the statement should not be informative. Yet it is. The discovery that Hesperus = Phosphorus was (in its day) a great scientific achievement.

(ii) Empty names seem perfectly meaningful. Then whose identity do they reveal? If the only semantic function of a name is to tell us which individual a proposition is about, how can it tell us this when there is no such individual?

Theories of Proper Names

Many theories have been proposed about proper names, none of them entirely satisfactory.

1. The traditional theory

In traditional logic, proper names had no place at all. There were only two kinds of propositions: existential ("some men are philosophers") and universal ("all men are mortal"). The subjects of both consisted of a common name ("philosopher", "man") and a quantifier ("all", "some"). Proper names do not therefore signify any constitutuent of any propositon. Aquinas argued that this is because "the intellect" grasps a proposition, and the intellect understands by abstracting the "universal content" from sense perception. The "principle of singularity" that makes Socrates this individual, we cannot grasp at all, except indirectly, by "turning towards the sense appearance" (conversio ad phantasmata). See Summa Theologica q.86 a1 ([ http://www.newadvent.org/summa/108601.htm ]).

The obvious difficulty with this theory is that sentences containing names do seem to be informative, even when there is no object appearing to the senses.

2. The descriptive theory

The descriptive theory of proper names is the view that the meaning of a given use of a proper name is a set of properties that can be expressed as a description that picks out an object that satisfies the description. It is commonly held that Frege held such a view (the description being embedded in what he called the sense (Sinn) of the name. Certainly Russell seems to have espoused such a view in his early philosophical career (Sainsbury, R.M., Russell, London 1979).

So, according to the descriptivist theory of meaning, there's a description of the sense of proper names, and that description, like a definition, picks out the bearer of the name. The distinction between the embedded description and the bearer itslef is similar to that between the extension and the intension of a general term, or between Connotation and denotation.

The extension of a general term like "dog" is just all the dogs that are out there; the extension is what the word can be used to refer to. The intension of a general term is basically a description of what all dogs have in common; it's what the definition expresses.

The difficulty with the descriptive theory is what the description corresponds to. It must be some essential characteristic of the bearer, otherwise we could use the name to deny the bearer had such a charaacteristic. The objection is associated with Kripke, although philosophers such as Bradley, Locke and Aristotle had already noticed the problem.

3. The referential theory

The referential theory is that the meaning of a proper name is simply the individual to which, in the context of its use, the name refers.

Another name for the theory is the "Fido"-Fido theory - because the name "Fido" refers to, or denotes, or picks out, well, Fido. So the name "Fido" means the dog Fido. But now wait a minute. Lots of dogs have been named "Fido." Lots of people have been named "Larry." The referential theory talks about proper names as though there's only one thing that any proper name, such as "Fido," can mean. Right? It says: "the meaning of a proper name is the individual," that one item, "to which it refers." But then isn't that wrong, to say that a proper name like "Fido" can mean any one dog in particular?

Not really, because when we use proper names, we usually understand by the total context which individual we're using the proper name to pick out. So when I said that the name "Larry" means me, you all understood, of course, that when I used the name "Larry" it meant one of the gazillions of guys named "Larry." But just to be clear, let's update the statement of the referential theory, so it includes this stuff about context.

It might be the case that the name "Fido" picks out lots of different dogs; but a given use of the name refers to just one of the animals named "Fido."

3. The Causal Theory of Names

This combines the referential view, with the idea that the name's referent is fixed by a baptismal act, whereupon the name becomes a rigid designator of the referent. Subsequent uses of the name succeed in referring to the referent by being linked by a causal chain to that original baptismal act. (The theory is an attempt to explain exactly why a proper name has the referent that it actually does).

See: Alex, Singular term

http://www.wikipedia.org/wiki/Proper_names

Larry's Text (to be moved to Sense and reference

I suppose this looks like a very reasonable theory. But consider now the following objection, which is due to the extremely influential German philosopher and logician, Gottlob Frege, who worked mainly in the late nineteenth century. He wrote a famous article called "On Sense and Reference", in which he said that proper names have two different kinds of meaning: not only their reference, but also their sense. So Frege said that there was more to the meaning of proper names than what they referred to. You also have to consider their sense, he said.

Consider examples like the following. Suppose you know that the name "Cicero" refers to a famous ancient Roman statesman. Well if you didn't know that then you do now. Suppose I tell you next that the name "Tully" refers to an ancient philosopher who was also an orator. I'm sure most of you didn't know that. But now consider. If I were to tell you, "Cicero is Cicero," you'd say, "Yeah, so?" You haven't learned anything then. But if I tell you, "Cicero is Tully," then you have learned something -- and that's a matter of fact, indeed Cicero is Tully; the man's full name was Marcus Tullius Cicero. Well, the argument goes, the only way it can be informative to say that Cicero is Tully is if the two names, "Cicero" and "Tully," differ somehow in their meanings. They have, as Frege said, different senses.

Let me give you another example. Both of the examples are totally hackneyed but if you're going to get a traditional introduction to the theory of meaning then you've got to be exposed to them! There is bright point of light which appears in the morning sky, just before sunrise, called "the Morning Star"; and similarly, just after sunset sometimes you can see a bright point of light in the sky, and this has been called "the Evening Star." And so the proper name, "the Morning Star," refers to a particular celestial object that appears the morning; and the proper name, "the Evening Star," refers to a particular celestial object that appears in the evening. And well, you've probably guessed it -- in fact the Morning Star is the Evening Star, and they are both the planet Venus and not a star at all.

So you've been informed and enlightened; you've been told that the two different names actually refer to the same thing, and you (probably) didn't know that before. If the two names had exactly the same meaning, though, how could it be informative or enlightening to be told that the two names refer to the same thing? They couldn't. So "the Evening Star" must differ somehow in its meaning from "the Morning Star." Since they refer to the same thing, namely Venus, it must be something else about their meaning that differs. And this other thing we call sense. So the sense of "the Morning Star" differs from the sense of the "Evening Star." Frege then said that a proper name denotes its reference and expresses its sense.

So then what sort of thing is a sense? It's basically like a description of a thing the word refers to; you can regard the following as a definition of "sense":

The sense of a proper name is a set of properties that can be expressed as a description that picks out the reference of the name.

To take an example: the sense of "the Morning Star" would be a set of properties that can be expressed as a description; and that description would pick out the planet Venus from among all the other stars and planets in the sky. So the description might be: "the brightest natural object in the sky, aside from the sun and the moon, which appears occasionally before sunrise." Something like that description would express the sense of "the Morning Star." And then how would the description of the sense of "the Evening Star" go? Maybe like this: "the brightest natural object in the sky, aside from the sun and the moon, which appears occasionally after sunset."

Now remember, we started out our discussion of proper names with the referential theory, the "Fido"-Fido Theory, which says that the meaning of a proper name is simply the thing to which it refers. But now if we say, with Frege and some others, that proper names have a sense as well as a reference, then we have to change our theory. So here's the new theory: