GOTTLOB FREGE THEORY OF MEANING

GOTTLOB FREGE

This Frege's influential theory of meaning, the theory of sense and reference was first outlined, albeit briefly, in his article, “Function and Concept” of 1891, and was expanded and explained in greater detail in perhaps his most famous work, “On Sense and Reference” of 1892. In “Function and Concept”, the distinction between the sense and reference of signs in language is first made in regard to mathematical equations, and in Fregean terminology, an expression is said to express its sense, and denote or refer to its reference.

The distinction between reference and sense was expanded, primarily in “On Sense and Reference” as holding not only for mathematical expressions, but for all linguistic expressions (whether the language in question is natural language or a formal language). The sense of a sign is that which competent speakers will grasp in virtue of their understanding of it (and the sense of a complete sentence is the context of the thought which it expresses for those who understand it), whereas the reference of a sign is that item in the world (in the case of a sentence, truth-value) which we speak about when we use it. One of his primary examples therein involves the expressions "the morning star" and "the evening star". Both of these expressions refer to the planet Venus, yet they obviously denote Venus in virtue of different properties that it has. Thus, Frege claims that these two expressions have the same reference but different senses. The reference of an expression is the actual thing corresponding to it, in the case of "the morning star", the reference is the planet Venus itself. The sense of an expression, however, is the "mode of presentation" or cognitive content associated with the expression in virtue of which the reference is picked out.

            Furthermore, for Frege, the relation between sense and reference are as follows: the truth-value of a sentence is held to depend upon the reference of the component expressions of that sentence, and the reference of those expressions in turn, to depend upon their sense. There is thus, a non-symmetric dependence of truth-value upon reference, and of reference upon sense, which can be expressed by saying that sense determines reference and reference determines truth-value. The idea is that it is in virtue of the fact that an expression has the sense which it does; it is also in virtue of the fact that an expression refers to the item in the world which it does, and finally, it is in virtue of having the reference which it does that sentences containing it have the truth-values which they do.

            In drawing this distinction, Frege ultimately argues that there can be no such thing as bare knowledge of reference. He avers that we cannot simply devise a theory which assigns referents to the various component expressions of the language, and hence which assigns truth-conditions to the completed sentences of the language, and leave it at that. Rather, says Frege, we want from a theory of meaning, an account of what it is for a speaker to understand their language, and understanding is surely a cognitive state of some sort. So, with each expression, there must be associated an immediate object of knowledge, which will constitute the speaker’s mode of thinking about the referent. This will be the sense of that expression.

            However, this Fregean strand leaves us puzzled as to the possibility for a sentence, most obviously a statement of identity, to convey information.

Frege then puts the distinction between sense and reference to work in solving a puzzle concerning identity claims. If we consider the two claims:

(1) The morning star = the morning star

(2) The morning star = the evening star

The first appears to be a trivial case of the law of self-identity, knowable a priori, while the second seems to be something that was discovered a posteriori by astronomers. However, if “the morning star” means the same thing as “the evening star”, then the two statements themselves would also seem to have the same meaning, both involving a thing's relation of identity to itself. On this basis, it then becomes too difficult to explain why (2) seems informative while (1) does not. Frege’s response to this puzzle, given the distinction between sense and reference, is that, because ,the reference of “the evening star” and “the morning star” are the same, both statements are true in virtue of the same object’s relation of identity to itself. However, because the senses of these expressions are different--in (1) the object is presented the same way twice, and in (2) it is presented in two different ways--it is informative to learn of (2). While the truth of an identity statement involves only the references of the component expressions, the informativity of such statements involves additionally the way in which those references are determined, i.e. the senses of the component expressions. Hence, while it is important to know that a particular individual is the referent of a proper name, it is also very important to be abreast with the means of identifying or ‘picking-out’ that individual. The mode, then, of determining the reference of an expression which a speaker employs, in Frege’s terminology, is the sense which that speaker attaches to it.

Furthermore, for Frege, this distinction applies also to other sorts of expressions and even whole sentences or propositions. If the sense/reference distinction can be applied to whole propositions, it stands to reason that the reference of the whole proposition depends on the references of the parts and the sense of the proposition depends of the senses of the parts. (At some points, Frege even suggests that the sense of a whole proposition is composed of the senses of the component expressions.) In the example considered in the above, it was seen that the truth-value of the identity claim depends on the references of the component expressions, while the informativity of what was understood by the identity claim depends on the senses.

For this and other reasons, Frege concludes that the reference of an entire proposition is its truth-value, either the True or the False. The sense of a complete proposition is what it is we understand when we understand a proposition, which Frege calls “a thought.” Just as the sense of a name of an object determines how that object is presented, the sense of a proposition determines a method of determination for a truth-value.

Again, Frege’s notion of sense underpins a theory of communication. Understanding the statements of another requires a grasp of the thoughts expressed. Where cognitive content refers to the mode of thinking associated with an expression in the idiolect of a particular speaker, and semantic content refers to that of which mutual knowledge is required for linguistic communication, Frege’s thesis is that cognitive and semantic content are one and the same.

In conclusion, for Frege, sense is a reflection of the cognitive significance drawn from sensory perceptions which ultimately affects the manner in which one conceives the reference.