rigid designator: a standalone construct

Saul Kripke introduced the term in his 1970 Princeton lectures, first published in 1972 and reissued in 1980 as the book Naming and Necessity, to mark a distinction in how words pick out things. A rigid designator is a term that refers to the same object in every possible world (every way things might have gone) in which that object exists, and never to anything else, so a proper name like 'Aristotle' stays fixed on one individual even when we imagine how his life might have turned out differently. Kripke set this against a description such as 'the teacher of Alexander', which could have picked out a different person had history run otherwise and so is not rigid. The construct is distinctive because it separates the fixing of reference from the giving of meaning: a rigid designator can be attached to its object by an initial act of naming and then carried through counterfactual reasoning without being backed by any description the speaker could state. It underwrites Kripke's further claim that an identity statement joining two rigid designators, such as 'Hesperus is Phosphorus', is necessarily true if it is true at all, a result that reshaped debates in metaphysics and the theory of reference.[1][2][3]

Unit

A referring expression, classified by whether its referent stays fixed across every counterfactual description of the world

Recovery means

Not applicable

Measured by

Identified by a modal test: whether the term picks out the same object under every counterfactual description of how the world might have been, as opposed to a term whose referent could have differed