Thinker · TH-0374
Saul Kripke
Saul Kripke was an American logician and philosopher who taught at Harvard, Rockefeller University, Princeton and the City University of New York. While still…
Also known as Saul A. Kripke
1940 – 2022 · Omaha, Nebraska; Cambridge, Massachusetts; Princeton; New York
Traditions: Analytic
Saul Kripke was an American logician and philosopher who taught at Harvard, Rockefeller University, Princeton and the City University of New York. While still a teenager he developed a possible-worlds semantics for modal logic, putting the subject on a secure footing. In the lectures published as Naming and Necessity he argued that names refer directly rather than through descriptions, and that some necessary truths, such as that water is H₂O, are known only a posteriori. He held that possible worlds are stipulated, not discovered.
Key ideas
- Modal logics can be given a model theory using possible worlds and accessibility relations.
- Proper names are rigid designators, referring to the same object in every possible world.
- Reference is fixed by a causal-historical chain, not by descriptions the speaker associates with a name.
- There are necessary truths known a posteriori and contingent truths known a priori.
Major works
- "Semantical Considerations on Modal Logic" (1963)
- Naming and Necessity (1980)
- Wittgenstein on Rules and Private Language (1982)
In the conversation
- Question My daughter asked whether a square circle could exist on another planet. How do I answer?
- Question Why do philosophers say “in some possible world” instead of just “possibly”?
- Question Kripke’s Gödel and Schmidt case: why would my word still pick out Gödel?
- Discussion I use modal logic at work every day, and the engineers around me have no idea it was philosophy
- Question If I can conceive it without contradiction, is it possible? Ash’arites, Hume and Kripke
- Reading group Reading group: Kripke, Naming and Necessity, Lectures I and II
- Debate S5 is the right logic for metaphysical necessity
- Question How did Kripke’s possible worlds turn S4 and S5 from arbitrary axioms into something meaningful?
- Reading group Reading group: David Lewis, On the Plurality of Worlds (1986), chapters 1–4