Much of twentieth-century analytic philosophy had given a definite answer to the question "what does a name mean?": on the view descending from Frege and Russell, a proper name like "Aristotle" is really a hidden description — such as "the philosopher who taught Alexander." What made the name meaningful was the bundle of descriptions we attached to it. In three lectures given at Princeton in 1970 (published in 1980 as "Naming and Necessity"), the young Saul Kripke (1940–2022) demolished this established view.

Kripke's counter-example was striking: the name "Aristotle" still refers to that person even if none of the descriptions we attribute to him are true. Even had Aristotle never taught, "Aristotle" would still name that man. So a name attaches to its object not through a description but through a kind of initial "baptism," and that link points to the same object in all possible situations. Kripke called this a "rigid designator."

This seemingly technical distinction had deep consequences. Kripke showed that two distinctions long thought identical are in fact different: "necessary/contingent" (whether a thing could have been otherwise) is a metaphysical distinction; "a priori/a posteriori" (known before/after experience) is an epistemic one. Contrary to custom, there are truths learned by experience yet still necessary — for example, "water is H₂O" was found by experiment and yet, if true, is necessarily true; water could not have been anything else.

These views reshaped the philosophy of language, metaphysics, and the philosophy of mind; they made talk of "possible worlds" a standard tool of philosophy. Kripke is counted among the most influential analytic philosophers of the late twentieth century — he showed that even where logic looks coldest, metaphysics is alive.