Kai Frederick Wehmeier (born 1968) is a German-American

philosopher A philosopher is a person who practices or investigates philosophy. The term ''philosopher'' comes from the grc, φιλόσοφος, , translit=philosophos, meaning 'lover of wisdom'. The coining of the term has been attributed to the Greek th ...

and

logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premi ...

ian. He is best known for proving that the fragment of Frege's

inconsistent In classical deductive logic, a consistent theory is one that does not lead to a logical contradiction. The lack of contradiction can be defined in either semantic or syntactic terms. The semantic definition states that a theory is consistent i ...

logical theory of ''Grundgesetze der Arithmetik'' becomes consistent upon restricting the complexity of comprehension formulas in the second-order comprehension schema to

\Delta^1_1

, for his development of a system of

subjunctive The subjunctive (also known as conjunctive in some languages) is a grammatical mood, a feature of the utterance that indicates the speaker's attitude towards it. Subjunctive forms of verbs are typically used to express various states of unreality s ...

modal logic Modal logic is a collection of formal systems developed to represent statements about necessity and possibility. It plays a major role in philosophy of language, epistemology, metaphysics, and natural language semantics. Modal logics extend other ...

and its use in rebutting Kripke's modal argument against description theories of proper names, as well as for refining and defending the thesis that there is no binary identity relation between objects. Wehmeier is currently a professor in the Department of Logic and Philosophy of Science and the Department of Philosophy at the

University of California, Irvine The University of California, Irvine (UCI or UC Irvine) is a public land-grant research university in Irvine, California. One of the ten campuses of the University of California system, UCI offers 87 undergraduate degrees and 129 graduate and p ...

. He is also the director of UC Irvine's Center for the Advancement of Logic, its Philosophy, History, and Applications (C-ALPHA).Wehmeier's website
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Selected publications

* "Consistent Fragments of ''Grundgesetze'' and the Existence of Non-Logical Objects," '' Synthese'' 121, 1999, pp. 309–328. * "In the Mood," '' Journal of Philosophical Logic'' 33, 2004, pp. 607–630. * "How to live without identity—and why," '' Australasian Journal of Philosophy'' 90, 2012, pp. 761–777. * "Subjunctivity and Conditionals," ''

The Journal of Philosophy ''The Journal of Philosophy'' is a monthly peer-reviewed academic journal on philosophy, founded in 1904 at Columbia University. Its stated purpose is "To publish philosophical articles of current interest and encourage the interchange of ideas, es ...

'' 110, 2013, pp. 117–142.

External links

Wehmeier's personal website

Center for the Advancement of Logic, its Philosophy, History, and Applications (C-ALPHA)

Notes and references

{{DEFAULTSORT:Wehmeier, Kai 1968 births Living people 20th-century American philosophers 21st-century American philosophers American logicians University of California, Irvine faculty