Sense and reference

The distinction between Sense and Reference was an innovation of the German philosopher and mathematician Gottlob Frege in 1892, reflecting the two ways he believed a singular term (usually understood as a proper name) may have meaning.

Broadly the reference (or "referent") of a proper name is the object it means or indicates. The sense of a proper name is whatever meaning it has, when there is no object to be indicated. Frege justifies the distinction in a number of ways.

1. Sense is something possessed by an name, whether or not it has a reference. For example the name "Odysseus" is intelligible, and therefore has a sense, even though there is no individual object (its reference) to which the name corresponds.

2. Sense is wholly semantic. Reference by contrast, though semantic, is intimately (and puzzingly) connected with the named object. Frege argues that Mont Blanc "with its snowfields" cannot be a component of the thought that Mont Blanc is more than 4,000 metres high (letter to Russell). But if we find the same word in two sentences, e.g. "Etna", then we also we recognise something common to the corresponding thoughts [my emphasis], something corresponding to the word "Etna".

3. The sense of different names is different, even when their reference is the same. Frege argues, in what is probably his most famous philosophical essay, that if an identity statement ("Hesperus is the same planet as Phosophorus") is to be informative, the proper names flanking the identity sign must have a different meaning or sense. But clearly, if the statement is true, they must have the same reference.

The idea has given rise to much famous disputation. Gareth Evans, for example, has argued that Frege held a Russellian theory of names[?], according to which there are no thoughts corresponding to empty names. His argument faces the difficulty that Frege did indeed hold we can express a thought using the name "Odysseus".

The distinction is commonly confused with that between connotation and denotation. (A distinction which predates Frege, famously interpreted by Mill). The "connotation" of a concept-word[?] like "planet" is the concept that the concept-word refers to. Denotation is any object (such as Venus or Mars) which, in Frege's terminology, falls under or satisfies[?] the concept.

External Link:

• Gottlob Frege: Über Sinn und Bedeutung (.pdf) (http://fizmo.bei.t-online.de/FregeSinn.pdf) (German Text)