On Sense and Reference

Agora

Work · Analytic Philosophy

On Sense and Reference

1892 · by Gottlob Frege

The Evening Star is the Morning Star – but not in the same sense.

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Introduction

The essay appeared in 1892 in the Zeitschrift für Philosophie und philosophische Kritik. Frege starts from a puzzle: “a = a” is trivial and known a priori, whereas “a = b” can record an astronomical discovery. His solution distinguishes the reference (Bedeutung) of an expression, the object it stands for, from its sense (Sinn), the way in which that object is presented. He extends the distinction to whole sentences: their sense is a thought, their reference a truth value. In indirect speech, as in “Copernicus believed that the planetary orbits are circles”, expressions refer to their ordinary sense. With “Function and Concept” (1891) and “On Concept and Object” (1892), the essay is a foundation of modern philosophy of language.