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Saul Aaron Kripke

educator , researcher

Saul Aaron Kripke, American philosophy educator, researcher. Grantee National Endowment of the Humanities, 1998, National Science Foundation; named one of New York's Influentials, New York Magazine, 2006. Fellow American Academy Art and Sciences, British Academy; member Association for Symbolic Logic (executive committee 1997-1999).


Kripke, Saul Aaron was born on November 13, 1940 in Bay Shore, New York, United States. Son of Myer Samuel and Dorothy E. Kripke.


Bachelor, Harvard University, 1962. Doctor of Humane Letters (honorary), University Nebraska, 1977. Doctor of Humane Letters (honorary), Johns Hopkins University, 1997.

Doctor of Humane Letters (honorary), University Haifa, Israel, 1998.


Lecturer with rank of Assistant Professor Princeton University 1964-1966. Lecturer Harvard University 1966-1968. Association Professor Rockefeller University 1968-1972, Professor 1972-1976.

McCosh Professor, of Philosophy, Princeton University since 1977. Fellow', American Academy, of Arts and Sciences. Eorresp. Fellow, British Academy.

Fulbright Fellow 1962-1963. Guggenheim Fellow 1968-1969, 1977-1978. Visiting Fellow, All Souls College Oxford 1977-1978, 90.

Other visiting professorships etc. Honorary D.Hum.Litt. (University of Neb. at Omaha). Professional.



Kripke’s remarkable career commenced with the publication of his first paper when he was nineteen years of age. Thereafter his work in logic provide a major impetus to the development of ‘possib world’ semantics, an approach which has had a

wide application in philosophy. Having its origins >n the Leibnizian idea of necessary truth as truth >n all possible worlds, it provided a systematic framework for clarifying problems arising in relation to the plethora of already existing systems °f modal logic.

These systems, while formally well developed, had yet to be provided with a satisfactory semantics. Among the other applications in which Kripke has played a leading part are those to do with intuitionistic logic, which is of Particular interest and concern for philosophers °f mathematics. Such was the potential of this framework, that it took in studies of all manner of notions over and above the basic modalities of necessity and possibility.

This very diversity of modal logics posed Problems, for the question immediately arose of whether there was any overall unifying perspective under which modal inferences could be systemutically treated.

Unfortunately some of the best known of these logical systems delivered different accounts of what qualified as correct inferences. It Was all very well to have elegantly presented axiomatic systems, but without proper interpretahon it was impossible to supply any definition of validity, and hence any satisfactory proofs of completeness for such systems. At best, logicians Managed to give rather informal readings of their logical operators of necessity or possibility.

The distinctiveness of Kripke's approach was in his definition of what he described as a ‘modelstructure’. comprising a set of possible worlds w*th relations of accessibility or ‘relative possibility' between those worlds. So, with respect to any 8>ven modal logic, the model assigns a truth-value to each atomic formula or proposition. So any gtven formula is either true or false in, or at, a w°rld in the set.

Kripke then defined the notion of validity for the given logic, a formula being valid lr| this sense if it came out true in all models. He Went on to develop quantified modal logic, i.e. ’hat which deals with modalized formulae involv,ng the apparatus of quantification.

In this logic an ‘nterpretation is provided for predicate expresSl°ns, specifying the sets of objects to be assigned,0 those expressions. In this way Kripke supplied *he desired overall framework for accommodatlng the different logics—the same fundamental Jdeas were in play, the individual systems emb°dying specific restrictions or conditions imP°sed on the relations between worlds. Subsequently Kripke has gone on to make P'oneering contributions to the theory of truth ar|d the analysis of the more recalcitrant of the logical and semantic paradoxes, as well as further developments in the field of quantification theory.

He made his greatest impact in a series of lectures (1970) which appeared in revised form in 1980.

At the centre of his analysis was an assault on the long-cherished distinction between necessary and a posteriori truths. It was here that Kripke introduced his famous idea of the ‘rigid designator' in his discussion of proper names, a topic which had already received extensive treatment since Russell’s analysis of 1905. Kripke's thesis was that proper names pick out their bearers or referents quite independently of any descriptions that might be associated with them.

Additionally, he espoused what is known as the causal theory of meaning, i.e. that speakers' use of names is grounded ultimately in an original ‘dubbing' of the object with the name, and subsequent use is sustained by a causal chain reaching back to that original episode in which the name was first assigned to the object. This had the immediate implication that names were not to be construed as in any way equivalent in meaning to any associated description or set of descriptions, and this in turn entailed dispensing with any Fregean-type distinction between the sense and reference of terms. Kripke’s view also had the consequence that identity statements featuring only proper names were, if true, necessarily true.

There were immediate implications here for the philosophy of mind: some of the proponents of the view known as ‘central state' materialism had stressed the contingency of the identity of thoughts and brain processes: now the idea of contingent identity was in question.

Another interesting outcome of Kripke’s work was a renewed interest in the issue of essentialism, i.e. in whether a distinction between an entity’s essential and its merely contingent properties was sustainable. At an intuitive level it seems quite natural to say that some properties are essential to an object or a person, as Kripke would say that having a specific biological parentage was essential to an individual, whereas their becoming a famous philosopher was not. The distinction, and Kripke’s account, continues to be hotly debated.

Kripke has not ceased to be controversial. In his 1982 monograph he ventured a provocative, and to some minds totally wrong-headed, interpretation of parts of Wittgenstein’s Philosophical Investigations according to which he attributes to Wittgenstein a comprehensively sceptical position on meaning and rule-following. His influence on both seniors and contemporaries has been considerable, sharpening up the debates with other and more extravagant possible-worlds theorists like David Lewis, and attracting a lengthy chapter of critical appraisal from the pro-Fregean Michael Dummett.

Others, like Hilary Putnam, have applied the notion of rigid designation to kind terms as well as individual terms. Inevitably, the notion of possible worlds has itself come into question despite its utility, and few have been convinced by Kripkc’s arguments for propositions which can be both necessary and a posteriori.


Fellow American Academy Art and Sciences, British Academy. Member Association for Symbolic Logic (executive committee 1997-1999).


  • Philosophers & Thinkers

    S. Kleene, Bertrand Russell, Alfred Tarski and Ludwig Wittgenstein.

  • Other Interests

    Logic; philosophy of language. Philosophy of mind.


Married Margaret P. Gilbert in 1976.

Myer Samuel Kripke

Dorothy Kripke

Margaret P. Gilbert