Saul Aaron Kripke (born November 13, 1940, Long Island, New York) is an American philosopher of language and logic and is one of the most influential thinkers in twentieth century Anglo-American analytical philosophy. He has a B.S. degree in mathematics from Harvard University, but no other formal qualifications. He is currently distinguished professor at City University of New York (CUNY) and has taught at Rockefeller University and Princeton University. In 2001, he was awarded the Rolf Schock Prize by the Royal Swedish Academy of Sciences, and delivered the John Locke Lectures at the University of Oxford in 1973.
Kripke is best known for a series of three lectures given at Princeton in 1970 collected together in the 1980 book Naming and Necessity which provided a radical analysis of names as being causally linked back to some kind of baptising event for the object, rather than being a coded definite description (as per the work of Gottlob Frege and Bertrand Russell). In the lectures, he drew a distinction between the categories of necessity and possibility, and the categories of the a priori and a posteriori - the former being metaphysically significant, while the latter being descriptions of epistemic knowledge. The categories had been seen as coextensive in the conventional view of philosophers like Immanuel Kant. Kripke explained that there are a class of necessary a posteriori propositions: "Heat is mean molecular motion", for instance, which is necessarily true, but not known without scientific investigation. Kripke has published work on the liar paradox, the difference between the way words refer semantically and the way that speaker's can use words to refer, and also on Ludwig Wittgenstein in a book titled Wittgenstein: On Rules and Private Language (1982). Kripke's interpretation of Wittgenstein has become so influential that it is often referred to as "Kripkenstein".
Kripke's life is a subject of wide interest and there are both truths and legends. Kripke's father, a rabbi and university lecturer, introduced him to René Descartes at age twelve. He was supposedly offered a job at Harvard University's mathematics department during his teenage years which he turned down because his mother thought it best that he finish high school. Kripke's first scholarly article was published in the Journal of Symbolic Logic at age 19. A student of Kripke's fictionalised him very negatively in a novel titled The Mind-Body Problem.