Frege on Sense and Reference

Gottlob Frege (1848–1925), a mathematician and logician at the University of Jena, is widely regarded as the founder of modern philosophy of language and the analytic tradition more broadly, chiefly through his Begriffsschrift (1879), which introduced the first fully adequate system of quantificational logic, and his later essay "Über Sinn und Bedeutung" ("On Sense and Reference," 1892), published in the Zeitschrift für Philosophie und philosophische Kritik. Frege's starting puzzle concerned identity statements: "the Morning Star is the Morning Star" is trivially true and uninformative, while "the Morning Star is the Evening Star" seemed to express the same identity between the same object, the planet Venus, yet was a genuine astronomical discovery, informative in a way the first statement was not. If the meaning of a name were simply the object it stood for (its Bedeutung, "reference" or "denotation"), the two statements should carry identical cognitive content, since they assert the identity of the same object with itself. Frege's solution was to distinguish a name's reference from its Sinn, "sense": the sense is the particular mode of presentation under which the referent is given to a thinker, so "the Morning Star" and "the Evening Star" share a reference (Venus) but differ in sense, each presenting the planet via a distinct set of associated descriptive information — one via its appearance at dawn, the other at dusk.