Saul Kripke

Saul Aaron Kripke (b. 1940, Omaha, Nebraska, Nebraska) is an American philosopher and logician now emeritus from Princeton and professor of philosophy at CUNY Graduate Center. He has been immensely influential in a number of fields related to logic and philosophy of language. Much of his work remains unpublished or exists only as tape-recordings and privately circulated manuscripts. He is nonetheless widely considered one of the most significant philosophers alive, and was the winner of the 2001 Schock Prize in Logic and Philosophy.

Modal logic

Two of Kripke's earlier works (A Completeness Theorem in Modal Logic and Semantical Considerations on Modal Logic) were very influential to modal logic. The most familiar logics in the modal family are constructed from a weak logic called K, named after Kripke because of his contributions to modal logic.

Related Topics:
Modal logic

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In Semantical Considerations on Modal Logic, published in 1963, Kripke responded to a difficulty with classical quantification theory. The whole motivation for the world-relative approach was to reflect the idea that objects in one world may fail to exist in another. If standard quantifier rules are used, however, every term must refer to something that exists in all the possible worlds. This seems incompatible with our ordinary practice of using terms to refer to things that only exist contingently.

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Kripke's response to this difficulty was to eliminate terms. He gave an example of a system that uses the world-relative interpretation and preserves the classical rules. However, the costs are severe. First, his language is artificially impoverished, and second, the rules for the propositional modal logic must be weakened.

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