Frege Quote on Sense and Reference: Meaning

Quote

"It is natural, now, to think of there being connected with a sign (name, combination of words, letter), besides that to which the sign refers, which may be called the reference of the sign, also what I should like to call the sense of the sign, wherein the mode of presentation is contained." — Gottlob Frege, "On Sense and Reference" (1892)

Historical Context

Gottlob Frege published "Über Sinn und Bedeutung" — "On Sense and Reference" — in 1892, and the essay immediately became a landmark in the philosophy of language. Frege was a mathematician and logician by training, and his philosophical work was driven by a desire to provide secure logical foundations for arithmetic. But in pursuing this project, he found himself grappling with questions about meaning that led him into territory that would later be called the philosophy of language. The Stanford Encyclopedia of Philosophy describes "On Sense and Reference" as one of the most cited papers in analytic philosophy, and its central distinction has shaped every subsequent discussion of meaning, reference, and semantic content.

The puzzle that motivated Frege was the problem of identity statements. Consider the statement "the morning star is the evening star." Both "the morning star" and "the evening star" refer to the same celestial body — the planet Venus. So the statement has the form "a = a," which is a trivial truth of logic and conveys no new information. But the statement "the morning star is the evening star" was a significant astronomical discovery, conveying genuine information. How can this be, if both expressions refer to the same thing?

Frege's predecessors had struggled with this puzzle. John Stuart Mill had held that proper names function simply as labels for their bearers — the meaning of a name is just the object it names. But if that were so, then "the morning star is the evening star" would be equivalent to "Venus is Venus," which is trivially true and uninformative. The puzzle suggested that Mill's view was missing something: that the meaning of an expression involves more than just the object it refers to.

Frege's intellectual context also included his own earlier work. In his Begriffsschrift (1879), Frege had treated identity as a relation between signs rather than between objects. But by 1892, he had come to see that this treatment was unsatisfying: it made identity dependent on the arbitrary choice of notation, when in fact identity statements seem to express genuine cognitive content. The distinction between sense and reference was Frege's solution to this problem, and it represented a fundamental rethinking of how language relates to the world.

Meaning and Interpretation

Frege's solution to the identity puzzle was to distinguish two aspects of meaning: sense (Sinn) and reference (Bedeutung). The reference of an expression is the object it picks out in the world. The reference of "the morning star" is Venus. The reference of "the evening star" is also Venus. Since they have the same reference, the identity statement "the morning star is the evening star" is true. But the sense of an expression is different: it is the "mode of presentation" — the way the object is presented or thought about. The sense of "the morning star" is the last star to disappear in the morning; the sense of "the evening star" is the first star to appear in the evening. These are different ways of thinking about the same object, and that is why the identity statement is informative: it tells us that two different modes of presentation pick out the same thing.

The quoted passage is the moment in the essay where Frege introduces this distinction. He says it is "natural" to think that a sign has not only a reference — the thing it stands for — but also a sense, which contains the "mode of presentation." The choice of the word "natural" is striking. Frege is not claiming to have discovered an esoteric philosophical truth; he is articulating a distinction that he thinks is implicit in our ordinary understanding of language. We already distinguish, in practice, between what a word refers to and how it refers to it. Frege's contribution was to make this distinction explicit and to show its philosophical power.

The implications of the sense-reference distinction extend far beyond the identity puzzle. Frege argued that sense is objective — it is not a private mental image or subjective association but a publicly accessible content that can be grasped by anyone who understands the language. Two people can share the same sense without sharing the same mental images, and a sense can exist even if no one currently grasps it. This objectivity of sense is what makes communication possible: when you speak and I understand, we share a sense, even though our private mental experiences may differ.

The distinction also has implications for the concept of truth. Frege held that the reference of a whole sentence is its truth value — True or False. This is a surprising claim, but it follows from his framework: if the reference of a name is an object, and the reference of a predicate is a concept, then the reference of a complete sentence should be something that remains constant when we substitute co-referential expressions. Since "the morning star is a planet" and "the evening star is a planet" have the same truth value, and since "the morning star" and "the evening star" have the same reference, Frege concluded that the reference of a sentence is its truth value. The sense of a sentence — what Frege called a "thought" (Gedanke) — is the proposition it expresses, which can be true or false and which can be shared by different sentences in different languages.

The sense-reference distinction has been enormously influential. It shaped Russell's theory of descriptions, which offered a different solution to the identity puzzle by treating definite descriptions as quantified phrases rather than names. It shaped Wittgenstein's early work, which built on Frege's distinction between sense and reference. And it shaped the entire tradition of formal semantics that developed in the twentieth century, from Donald Davidson's truth-conditional semantics to Saul Kripke's causal theory of reference. The Stanford Encyclopedia of Philosophy notes that while many details of Frege's view have been challenged and modified, the basic distinction between the semantic content of an expression (how it presents its object) and its referent (the object it picks out) remains a foundational tool for thinking about how language works.

Frege's insight also connects to broader philosophical questions about knowledge and meaning. If the sense of an expression is its mode of presentation, then understanding a language involves grasping the senses of its expressions — knowing not just what they refer to but how they refer. This suggests that meaning is richer than reference: there is more to understanding a word than knowing what object it picks out. This insight has resonated far beyond the philosophy of language, influencing debates in the philosophy of mind about the content of mental states, in the philosophy of science about the meaning of theoretical terms, and in the philosophy of mathematics about the nature of mathematical objects. Frege's distinction, born from a puzzle about the morning star, turned out to illuminate some of the deepest questions about language, thought, and reality.