]> 2008/06/10 OpenCyc Knowledge Base Copyright© 2001-2008 Cycorp, Inc., http://www.cyc.com/, Austin, TX, USA This file contains an OWL representation of information contained in the OpenCyc Knowledge Base. The content of this OWL file is licensed under the Creative Commons Attribution 3.0 license whose text can be found at http://creativecommons.org/licenses/by/3.0/legalcode. The content of this OWL file, including the OpenCyc content it represents, constitutes the "Work" referred to in the Creative Commons license. The terms of this license equally apply to, without limitation, renamings and other logically equivalent reformulations of the content of this OWL file (or portions thereof) in any natural or formal language, as well as to derivations of this content or inclusion of it in other ontologies. externalID A unique, language-neutral, variable-sized identifier for a concept that can be used to refer unambiguously to that concept across OWL exports or across Cyc inference engines. label A natural-language representation for a concept that is both human readable and readable by the Cyc inference engine. These terms are not guaranteed to refer to the same concept across time but are guaranteed to be consistent within a particular OWL export. Use 'cycAnnot:externalID' for unambiguously referring to a concept across OWL exports or across Cyc inference engines. The collection of all people whose work involves the study and development of formal logic. Note that most logicians consider themselves either philosophers or mathematicians. logician Logician logicians LudwigWittgenstein Ludwig Wittgenstein AlfredTarski Alfred Tarski is, with <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvarT5ZwpEbGdrcN5Y29ycA" class="cyc_term">KurtGodel</a>, one of the founders of contemporary logic. His papers on the theory of truth and logical consequence, as well as his studies on axiomatic geometry, are commonly identified as the starting point of formal semantics and model theory. Born Alfred Teitelbaum in Russian-occupied Poland, he converted to Catholicism and changed his name to Tarski, apparently in an outburst of Polish nationalism following the Russian retreat in <font color="#ff0000">#$WorldWarI</font>. Whatever the motive, the conversion did little to mollify the numerous anti-semites in Polish academia: Tarski wrote his seminal papers while teaching mathematics in high school. He later moved to the United States and had a distinguished career at the University of California, where his students included Solomon Feferman and Richard Montague. Alfred Tarski Church was professor of mathematics at Princeton University and later professor of mathematics and philosophy at UCLA. His work has been greatly influential in the fields of mathematical logic, recursion theory, and theoretical computer science. At the time of his death, Church was widely regarded as the greatest living logician in the world. Among his greatest contributions: the lambda calculus, Church's Thesis (every effectively computable function can be computed by a recursive function). Alonzo Church AlonzoChurch BertrandRussell Bertrand Russell <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViLgpwpEbGdrcN5Y29ycA" class="cyc_term">BertrandRussell</a> was a philosopher whose most influential contributions include his defense of logicism and his theories of definite descriptions and logical atomism. Russell is generally recognized as one of the founders of analytic philosophy. Along with <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvarT5ZwpEbGdrcN5Y29ycA" class="cyc_term">KurtGodel</a>, he is also often credited with being one of the two most important logicians of the twentieth century. Imprisoned in 1918 for pacifism, he was increasingly engaged in political activities. In 1950 he won the <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvzn-O5wpEbGdrcN5Y29ycA" class="cyc_term">NobelPrizeForLiterature_1950</a>. AlbertThoralfSkolem Albert Skolem AugustusDeMorgan Augustus De Morgan CharlesPeirce <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvwMvxJwpEbGdrcN5Y29ycA" class="cyc_term">CharlesPeirce</a> was the first significant American <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rv-Pbe5wpEbGdrcN5Y29ycA" class="cyc_term">Logician</a>. Charles Peirce <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rv4kaJ5wpEbGdrcN5Y29ycA" class="cyc_term">GottlobFrege</a> was one of the founders of modern symbolic logic. GottlobFrege Gottlob Frege StephenCKleene Stephen Kleene A student of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rr9CCkSGgEdaaVQBQ2sS97Q" class="cyc_term">AlonzoChurch</a> and one of the greatest logicians of the 20th century. <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rr9CpoSGgEdaaVQBQ2sS97Q" class="cyc_term">StephenCKleene</a>'s greatest influence was on theory of computability, both in its mathematical and philosophical aspects. Among its greatest contributions: the development of the theory of degrees of computability, computable ordinals and the arithmetic hierarchy; recursive realizability, an intepretation of intuitionistic mathematics in computability theory. The most important logician of the twentieth century. He demonstrated the completeness of the first-order predicate calculus and the incompleteness of any formal system strong enough to demonstrate the truths of Peano arithmetic. He also made important contributions to <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rv36W7ZwpEbGdrcN5Y29ycA" class="cyc_term">SetTheory</a> and to <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViOapwpEbGdrcN5Y29ycA" class="cyc_term">Physics</a>. KurtGodel Kurt Godel ErnstZermelo Ernst Zermelo StanislawLesniewski Stanislaw Lesniewski person A specialization of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViknpwpEbGdrcN5Y29ycA" class="cyc_term">SocialBeing</a> and <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVilYpwpEbGdrcN5Y29ycA" class="cyc_term">IndividualAgent</a>: the collection of all persons. Personhood is a vague, emotionally loaded yet extremely salient concept with respect to common-sense reasoning. Something is an instance of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViAkpwpEbGdrcN5Y29ycA" class="cyc_term">Person</a> if it is an individual <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVinb5wpEbGdrcN5Y29ycA" class="cyc_term">IntelligentAgent</a> with perceptual sensibility, capable of complex social relationships, and possessing a certain moral sophistication and an intrinsic moral value, or -- if it lacks certain of these characteristics -- is a member of a distinct type of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViknpwpEbGdrcN5Y29ycA" class="cyc_term">SocialBeing</a> (usually a species) which generally possesses such characteristics and is therefore acknowledged by other members of that type as a person within their social systems. Most currently known instances of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViAkpwpEbGdrcN5Y29ycA" class="cyc_term">Person</a> are instances of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rIcwFloGUQdeMlsOWYLFB2w" class="cyc_term">HomoSapiens</a> but there is no reason why all need be (consider <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvdRsSZwpEbGdrcN5Y29ycA" class="cyc_term">Hobbit</a>s in the fictional world of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVi8lZwpEbGdrcN5Y29ycA" class="cyc_term">LordOfTheRings_Trilogy</a>). They need not even be instances of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVim7ZwpEbGdrcN5Y29ycA" class="cyc_term">BiologicalLivingObject</a> (consider the possibility of a person-like AI). Also note that <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViAkpwpEbGdrcN5Y29ycA" class="cyc_term">Person</a> excludes non-human &quot;legal persons&quot;, who are, however, included in the collection <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVinsZwpEbGdrcN5Y29ycA" class="cyc_term">LegalAgent</a>. Person Pretty String (<a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rwLSVCpwpEbGdrcN5Y29ycA" class="cyc_term">prettyString</a> TERM STRING) means that STRING is the English word or expression (sequence of words) commonly used to refer to TERM. The predicate <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rwLSVCpwpEbGdrcN5Y29ycA" class="cyc_term">prettyString</a> is used by the code which generates CycL to English paraphrases, but its applicability is not restricted to this use. prettyString The collection of all people whose work involves the study and development of formal logic. Note that most logicians consider themselves either philosophers or mathematicians. logician Logician The collection of all people whose work involves the study and development of formal logic. Note that most logicians consider themselves either philosophers or mathematicians. logician Logician The collection of all people whose work involves the study and development of formal logic. Note that most logicians consider themselves either philosophers or mathematicians. logician Logician type of person classified by activity PersonTypeByActivity A collection of collections. Each instance of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvWgxLZwpEbGdrcN5Y29ycA" class="cyc_term">PersonTypeByActivity</a> is a collection of <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViAkpwpEbGdrcN5Y29ycA" class="cyc_term">Person</a>s that classifies people by some kind of activity that they do on a regular basis. Examples include <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvViNGpwpEbGdrcN5Y29ycA" class="cyc_term">Student</a>, <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rwPfOI5wpEbGdrcN5Y29ycA" class="cyc_term">Tourist</a>, and <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rwQBaCpwpEbGdrcN5Y29ycA" class="cyc_term">HornPlayer</a>. If the differentiating activity is one that is normally done as a career or job, it is preferable to make the collection an instance of the more specific <a href="http://sw.opencyc.org/2008/06/10/concept/Mx4rvVii2ZwpEbGdrcN5Y29ycA" class="cyc_term">PersonTypeByOccupation</a> (q.v.).