21. PlanetMath: Gödel's Incompleteness Theorems The second version of Gödel s first incompleteness theorem suggests a natural wayto extend theories to stronger theories which are exactly as sound as the http://planetmath.org/encyclopedia/GodelsIncompletenessTheorems.html

(more info) Math for the people, by the people. Encyclopedia Requests Forums Docs ... Random Login create new user name: pass: forget your password? Main Menu sections Encyclop¦dia Papers Books Expositions meta Requests Orphanage Unclass'd Unproven ... Corrections talkback Polls Forums Feedback Bug Reports downloads Snapshots PM Book information Docs Classification News Legalese ... TODO List G¶del's incompleteness theorems (Theorem) logic , one can formulate properties of theories and sentences as arithmetical properties of the corresponding , thus allowing 1st order arithmetic to speak of its own consistency, provability of some sentence and so forth. On Formally Undecidable propositions in Principia Mathematica and Related Systems can be stated as Theorem No theory axiomatisable in the type system of PM (i.e., in Russell's theory of types ) which contains Peano-arithmetic and is -consistent proves all true theorems of arithmetic (and no false ones). Stated this way, the theorem is an obvious corollary of Tarski's result on the undefinability of truth formula , and by Tarski's result it isn't definable by any arithmetic formula. But assume there's a theory

22. Gödel On The Net Every day, Gödel s incompleteness theorem is invoked on the net to support someclaim or other, or just to whack people over the head with it in a general way http://www.sm.luth.se/~torkel/eget/godel.html

Gödel on the net Every day, Gödel's incompleteness theorem is invoked on the net to support some claim or other, or just to whack people over the head with it in a general way. In news, we find such invocations not only in sci.logic, sci.math, comp.ai.philosophy, sci.philosophy.tech and other such places where one might expect them, but with equal frequency in groups dealing with politics or religion, and indeed in alt.cuddle, soc.culture.malaysia, rec.music.hip-hop, and what have you. In short, whenever a bunch of people get together on the net, sooner or later somebody will invoke Gödel's incompleteness theorem. Unsurprisingly, the bulk of these invocations covers a range from the nonsensical to the merely technically inaccurate, and they often give rise to a flurry of corrections and more or less extended technical or philosophical disputes. My purpose in these pages is to provide a set of responses to many such invocations, couched in non-confrontational and hopefully helpful and intelligible terms. There are few technicalities, except in connection with a couple of technical (and less frequently raised) issues. All of my comments and explanations are intended to be non-controversial, in the sense that people who are familiar with the incompleteness theorem can be expected to agree with them. (Thus, for example, I don't present any criticism of so-called Gödelian arguments in the philosophy of mind, but only a couple of technical observations relevant for the discussion of such arguments.)

23. Gödel's Theorem Gödel s second incompleteness theorem. Gödels first incompletenesstheorem proves that formal systems T satisfying certain conditions http://www.sm.luth.se/~torkel/eget/godel/second.html

Gödel's second incompleteness theorem Gödels first incompleteness theorem proves that formal systems T satisfying "certain conditions" are incomplete, i.e. that there is a sentence A in the language of the T which can neither be proved, nor disproved in T. Among the "certain conditions" must be some condition implying that T is consistent. Gödel's second incompleteness theorem proves that formal systems T satisfying certain other conditions "cannot prove their own consistency", in the sense that a suitable formalization in the language of T of the statement "T is consistent" cannot be proved in T. Again one necessary condition is that T is in fact consistent, since otherwise everything is provable in T. The second incompleteness theorem applies in particular to those formal systems that can be used to develop all of the ordinary mathematics that one finds in textbooks. One such system is the axiomatic set theory called ZFC. Since all the theorems ordinarily proved in mathematics can be proved in ZFC, and since the consistency of ZFC cannot be proved in ZFC (unless ZFC is inconsistent), it is often concluded that we cannot expect to prove, and therefore can't know, that ZFC is consistent. "We can't know that mathematics is consistent." This is the conclusion discussed in this section. "Different" doesn't mean "stronger" In commenting on this, first let me mention a widespread misconception. Clearly, for any theory T, there is another theory T' in wich "T is consistent" can be proved. For example, we can trivially define such a theory T' obtained by adding "T is consistent" as a new axiom to T. The misconception consists in the notion that any such theory T' in which "T is consistent" is provable must be

24. Gödel's Incompleteness Theorem G?el s incompleteness theorem. In mathematical logic, Gödel s axiomatizationof set theory. These results do not require the incompleteness theorem. http://www.fact-index.com/g/go/goedel_s_incompleteness_theorem.html

Main Page See live article Alphabetical index Gödel's incompleteness theorem In mathematical logic are two celebrated theorems proved by Kurt Gödel in . Somewhat simplified, the first theorem states: In any consistent axiomatic system (formal system of mathematics) sufficiently strong to allow one to do basic arithmetic , one can construct a statement about natural numbers that can be neither proved nor disproved within that system. In this context, an axiomatic system is one with a recursive set of axioms; equivalently, the theorems of the system can be generated by a Turing machine . The statement which cannot be proved nor disproved in the system is furthermore true in the sense that what it asserts about the natural numbers in fact holds. Because the system fails to prove a true statement, it is said to be incomplete . In other words, then, Gödel's first incompleteness theorem says that any sufficiently strong formal system of mathematics is either inconsistent or incomplete. Gödel's second incompleteness theorem, which is proved by formalizing part of the proof of the first within the system itself, states: Any sufficiently strong consistent system cannot prove its own consistency.

25. Byunghan Kim S Homepage Lecture Notes. Complete proofs of Gödel s incompleteness theorems Course lectureon Gödel s incompleteness theorems. Hyperimaginaries and canonical bases http://www-math.mit.edu/~bkim/

Byunghan Kim Mailing Address: Room 2-171 Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge, MA 02139 Telephone: (617) 253-4385 Fax: (617) 253-4358 E-mail: bkim@math.mit.edu I am an Assistant Professor in Mathematics Department at the Massachusetts Institute of Technology Brief CV Recent papers Stability, and simplicity in there. Around stable forking , (with A. Pillay). The notions around stable forking are studied. The geometry of 1-based minimal types , (with T. de Piro). The first chapter of geometric simplicity theory. A note on weak dividing , preprint (with N. Shi). The type-definable group configuration under the generalized type-amalgamation , preprint (with T. de Piro and J. Young). The canonical type(hyper)-definable group is obtained from a group configuration under 3-amalgamation. Examples around stable definability , preprint (with R. Moosa). Non-stable definability of ACF equipped with a generic relation, psedo-finite fields, ACFA is shown.

26. Gödel's Incompleteness Theorem - Encyclopedia Article About Gödel's Incomplete encyclopedia article about Gödel s incompleteness theorem. Gödel s incompletenesstheorem in Free online English dictionary, thesaurus and encyclopedia. http://encyclopedia.thefreedictionary.com/Gödel's incompleteness theorem

Dictionaries: General Computing Medical Legal Encyclopedia Gödel's incompleteness theorem Word: Word Starts with Ends with Definition In mathematical logic Mathematical logic is a discipline within mathematics, studying formal systems in relation to the way they encode intuitive concepts of proof and computation. As a matter of history, it was developed to understand and present the work of Kurt Gödel on the foundations of mathematics. See the list of mathematical logic topics. The extent of mathematical logic Although the layperson may think that mathematical logic is the Click the link for more information. are two celebrated theorems proved by Kurt Gödel [gö:dl], (April 28, 1906 - January 14, 1978) was a mathematician whose biography lists quite a few nations, although he is usually associated with Austria. He was born in Austria-Hungary (which broke up after World War I), became Czechoslovak citizen at age 12, and Austrian citizen at age 23. When Austrian-born Hitler annexed Austria, Gödel automatically became German at age 32. After WW-II, at age 42, he also obtained US citizenship in addition to his Austrian one. Click the link for more information.

27. Goedel's Incompleteness Theorem - Encyclopedia Article About Goedel's Incomplete IncompletenessTheorem Any adequate axiomatizable theory is incomplete. http://encyclopedia.thefreedictionary.com/Goedel's incompleteness theorem

Dictionaries: General Computing Medical Legal Encyclopedia Goedel's incompleteness theorem Word: Word Starts with Ends with Definition In mathematical logic Mathematical logic is a discipline within mathematics, studying formal systems in relation to the way they encode intuitive concepts of proof and computation. As a matter of history, it was developed to understand and present the work of Kurt Gödel on the foundations of mathematics. See the list of mathematical logic topics. The extent of mathematical logic Although the layperson may think that mathematical logic is the Click the link for more information. are two celebrated theorems proved by Kurt Gödel [gö:dl], (April 28, 1906 - January 14, 1978) was a mathematician whose biography lists quite a few nations, although he is usually associated with Austria. He was born in Austria-Hungary (which broke up after World War I), became Czechoslovak citizen at age 12, and Austrian citizen at age 23. When Austrian-born Hitler annexed Austria, Gödel automatically became German at age 32. After WW-II, at age 42, he also obtained US citizenship in addition to his Austrian one. Click the link for more information.

28. Godel's Incompleteness Theorem More precisely, his first incompleteness theorem states that in any formal systemS of arithmetic, there will be a sentence P of the language of S such that http://www.faragher.freeserve.co.uk/godeldef2.htm

Definitions Godel's Theorem. The proof, published by Kurt Godel in 1931, of the existence of formally undecidable propositions in any formal system of arithmetic. More precisely, his first incompleteness theorem  states that in any formal system S of arithmetic, there will be a sentence P of the language of S such that if S is consistent, neither P nor its negation can be proved in S .  This makes it possible to show that there must be a sentence P of S which can be interpreted (very roughly) as saying 'I am not provable'. It is shown that if S is consistent, this sentence is not provable, and hence, it is sometimes argued, P must be true. It is this last step which had led people to claim that Godel's theorem demonstrates the superiority of men over machines - men can prove propositions which no machine (programmed with the axioms and rules of a formal system) can prove. But this is to overlook the point that the proof of the theorem only allows one to conclude that if S is consistent, neither

29. Gödel's Incompleteness Theorem Gödel s incompleteness theorem. The proof of Gödel s incompleteness theoremis so simple, and so sneaky, that it is almost embarassing to relate. http://www.meta-religion.com/Mathematics/Articles/godel_theorem.htm

to promote a multidisciplinary view of the religious, spiritual and esoteric phenomena. About Us Links Search Contact ... Back to Mathematics Religion sections World Religions New R. Groups Ancient Religions Spirituality ... Extremism Science sections Archaeology Astronomy Linguistics Mathematics ... Contact The Web Metareligion More sections: Subscribe to the Metareligion Newsletter Submit your site Banners Index ... Polls Please, help us sustain this free site online. Make a donation using Paypal: Gödel's Incompleteness Theorem This theorem is one of the most important proven in this century, ranking with Einstein's Theory of Relativity and Heisenberg's Uncertainty Principle. However, very few people know about it. The excerpts below should, I hope, help explain it. A related page with some interesting links is Mårten Steinius' GEB Page. You can also look at The Kurt Gödel Society.

30. Gödel's Incompleteness Theorem :: Online Encyclopedia :: Information Genius Gödel s incompleteness theorem. Online Encyclopedia In mathematical settheory. These results do not require the incompleteness theorem. http://www.informationgenius.com/encyclopedia/g/go/godel_s_incompleteness_theore

Quantum Physics Pampered Chef Paintball Guns Cell Phone Reviews ... Science Articles Gödel's incompleteness theorem Online Encyclopedia In mathematical logic are two celebrated theorems proved by Kurt Gödel in . Somewhat simplified, the first theorem states: In any consistent axiomatic system (formal system of mathematics) sufficiently strong to allow one to do basic arithmetic , one can construct a statement about natural numbers that can be neither proved nor disproved within that system. In this context, an axiomatic system is one with a recursive set of axioms; equivalently, the theorems of the system can be generated by a Turing machine . The statement which cannot be proved nor disproved in the system is furthermore true in the sense that what it asserts about the natural numbers in fact holds. Because the system fails to prove a true statement, it is said to be incomplete . In other words, then, Gödel's first incompleteness theorem says that any sufficiently strong formal system of mathematics is either inconsistent or incomplete. Gödel's second incompleteness theorem, which is proved by formalizing part of the proof of the first within the system itself, states:

31. Proof Of Gödel’s First Incompleteness Theorem Proof of Gödel’s first incompleteness theorem. A proof of Emacs.Statement of Rosser’s incompleteness theorem for NN. (TSystem http://math.berkeley.edu/~roconnor/godel.html

A is given using the Coq proof assistant . This proof can be checked with Coq 7.3.1. T of the first order classical theory called NN (which is PA without induction) that can express its own axioms, there is a closed formula such that if either T proves or T proves ¬ then T is inconsistent. The secondary result is that PA is incomplete. There is a closed formula such that neither PA proves , nor PA proves ¬ . This follows from the fact that PA can express its own axioms and a proof that PA rosser.v , and the proof of the incompleteness of PA can be found in rosserPA.v The proof of incompleteness was loosely based on the proof given in An Introduction to Mathematical Logic by Richard E. Hodel ). Also supplementary text for the book Logic for Mathematics and Computer Science Finally, parts of the package for was used to prove the Chinese remainder theorem, and this package is included with the proof of incompleteness. Robert Schneck for introducing me to Coq, and helping me out at the beginning. (He gave me the coq definition for a Term in first order logic). This proof was developed using Proof General under Emacs.

32. Gödel's Incompleteness Theorem Gödel s incompleteness theorem. The a href= ../Logic/General.html Moredetails about Gödel s incompleteness theorem. /a . next http://cs.wwc.edu/~aabyan/CII/BOOK/book/node163.html

Next: The Halting Problem Up: Decision Problems Previous: Undecidable Contents A complete formal system is a formal system where all true theorems can be proved. An inconsistent formal system is a formal system where at least one false statement can be proved within the formal system. Due to the computational equivalence of formal systems to other computational capability, we get the Halting problem, the uncomputable numbers and other unsolvable problems. Next: The Halting Problem Up: Decision Problems Previous: Undecidable Contents Anthony A. Aaby 2003-11-11

33. Godel Vs. Artificial Intelligence Jeff Makey jeff@sdsc.edu 12 March 1995. Gödel s incompleteness theoremis Not an Obstacle to Artificial Intelligence. Artificial Intelligence. http://www.sdsc.edu/~jeff/Godel_vs_AI.html

Foreword by the Author I originally wrote this paper in 1981 for a course in writing research papers at Rose-Hulman Institute of Technology . It was written on a DEC PDP-11/70 computer using the RUNOFF text formatting program, and having it on line from the beginning made it easy to save an electronic copy for future use. The instructor, Dr. Peter Parshall (of "Peter Parshall picked apart my perfect paper" fame), awarded the grade of A- to my work. In 1995, with the World Wide Web available as a means of publication, I retrieved the original document from my archives and converted it to the HTML format seen here. Other than format conversions and the deletion of the bibliography (which the Notes section renders superfluous), the paper is exactly as I wrote it then. (Well, I also fixed a couple of spelling errors and added a missing word. These modifications are identified in the HTML source.) I am both gratified and disappointed that the conclusions I drew then are still valid. Jeff Makey jeff@sdsc.edu 12 March 1995 Artificial Intelligence. The idea of men building a machine which is capable of thinking, originating ideas, and responding to external stimuli in the same manner as a man might is fascinating to some people frightening to others. Whether or not artificial intelligence (or AI) is possible has been the subject of debate for quite some time now. As early as 1842, a memoir by Lady Ada Lovelace read: "The Analytical Engine has no pretentions whatever to originate anything. It can do whatever we know how to order it to perform."

34. Korean Article Bank incompleteness theorem. Wikipedia Gödel s ? ?. ? (incompleteness theorem) . http://theology.co.kr/wwwb/CrazyWWWBoard.cgi?db=koreabank&mode=read&num=303&page

35. Gödel's Incompleteness Theorem - Wikipedia, The Free Encyclopedia PhatNav s Encyclopedia A Wikipedia . Gödel s incompleteness theorem. Theseresults do not require the incompleteness theorem. http://www.phatnav.com/wiki/wiki.phtml?title=Gödel's_incompleteness_theorem

36. The Matrix Reloaded And The Incompleteness Theorem :: Ephilosopher :: Philosophy The City of God Augustine. The Matrix Reloaded and The IncompletenessTheorem Posted by Adimantis on Tuesday, September 23, 2003 0826 AM, http://www.ephilosopher.com/article623.html

@import url("themes/PostNukeBlue2/style/style.css"); E P H I L O S O P H E R Jun 06, 2004 - 02:14 AM Hey You! Want to join? or Login Search advanced web Main Menu Site Map Home QuickLinks Student Help Grad School Department Rankings Academic Jobs ... Philosophy Blogs Community Submissions Philosophy Forums Members List Suggested Books ... Top 10 Lists Archives 2000-4 Archives Special Sections Interviews Articles Columns EP Newsletter You are currently not logged in , but you can still subscribe to our newsletter. Blog Headlines Scepticism with a 'c' More Philosophy Department Blogs "Science isn't a democracy" Has Bush Lost His Mind? ... On Applying Twice to Grad Schools in Philosophy Quotables Anyone who has had a glimpse of the range and subtlety of the thought of Plato or of a Hegel will long ago have despaired of becoming a philosopher. - Experience and its Modes Michael Oakeshott The Matrix Reloaded and The Incompleteness Theorem Posted by: Adimantis on Tuesday, September 23, 2003 - 08:26 AM Article: The Matrix: Reloaded: Jesus, Buddha, and Gödel: Unraveling the Matrix Mythos , Eric Furze for Metaphilm Related: Kurt Gödel: Biography and Gödel, Escher, Bach: An Eternal Golden Braid

37. Godel's Incompleteness Theorems Godel s incompleteness theorems. Previous by thread Godel s IncompletenessTheorems; Next by thread Re Godel s incompleteness theorems; http://www.panmere.com/rosen/mhout/msg01115.html

ROSEN List Home Date Prev Date Next Thread Prev ... Search Godel's Incompleteness Theorems From Date : Fri, 26 Mar 2004 10:46:13 -0500 This is a correction to my original post. I inadvertently left out two prior paragraphs in the Rashevsky quote. Tim mailto:*** ]On Behalf Of James N -snip James, In addition to Judith's quote, I think another one from Essays on Life Itself that speaks to your question is this: "Any question becomes unanswerable if we do not permit ourselves a universe large enough to deal with the question. Ax=B is generally unsolvable in a universe of positive integers. Likewise, generic angles become untrisectable, cubes unduplicatable, and so on, in a universe limited by rulers and compasses. I claim that Godelian noncomputability results are a symptom, arising within mathematics itself, indicating that we are trying to solve problems in too limited a universe of discourse. The limits in question are imposed in mathematics by an excess of "rigor," and in science by cognate limitations of "objectivity" and "context independence." In both cases, our universes are limited, not by the demands of problems that need to be solved but by extraneous standards of rigor. The result, in both cases, is a mind-set of reductionism, of looking only downward toward subsystems, and never upward and outward." [EL 2] The possible impact of this for science, and biology in particular, is a few paragraphs later:

38. Re: Godel's Incompleteness Theorems Search Re Godel s incompleteness theorems. review; Next by Date OnModels; Previous by thread Godel s incompleteness theorems; Next http://www.panmere.com/rosen/mhout/msg01137.html

ROSEN List Home Date Prev Date Next Thread Prev ... Search Re: Godel's Incompleteness Theorems From Date : Sat, 27 Mar 2004 20:07:15 -0800 Follow-Ups Re: Godel's Incompleteness Theorems From: Tim Gwinn Re: Godel's Incompleteness Theorems From: Judith Rosen On Models From: Jack Park References Godel's Incompleteness Theorems From: Tim Gwinn Prev by Date: Re: Nature magazine article. review Next by Date: On Models Previous by thread: Godel's Incompleteness Theorems Next by thread: On Models Index(es): [ Date Index Thread Index Author Index Search

39. Online Encyclopedia - Gödel's Incompleteness Theorem , Encyclopedia Entry for Gödel s incompletenesstheorem. Dictionary Definition of Gödel s incompleteness theorem.......Encyclopedia http://www.yourencyclopedia.net/Gödel's_incompleteness_theorem.html

Encyclopedia Entry for Gödel's incompleteness theorem Dictionary Definition of Gödel's incompleteness theorem In mathematical logic are two celebrated theorems proved by Kurt Gödel in . Somewhat simplified, the first theorem states: In any consistent axiomatic system (formal system of mathematics) sufficiently strong to allow one to do basic arithmetic , one can construct a statement about natural numbers that can be neither proved nor disproved within that system. In this context, an axiomatic system is one with a recursive set of axioms; equivalently, the theorems of the system can be generated by a Turing machine . The statement which cannot be proved nor disproved in the system is furthermore true in the sense that what it asserts about the natural numbers in fact holds. Because the system fails to prove a true statement, it is said to be incomplete . In other words, then, Gödel's first incompleteness theorem says that any sufficiently strong formal system of mathematics is either inconsistent or incomplete. Gödel's second incompleteness theorem, which is proved by formalizing part of the proof of the first within the system itself, states:

40. Logic III: Gödel's Incompleteness Theorems - Phil 479 - Winter 04 - Richard Zac The first incompleteness theorem states that no recursive consistent arithmeticaltheory T is strong enough to decide all the sentences of arithmetic (ie http://www.ucalgary.ca/~rzach/479/

Richard Zach Home CV Teaching Publications ... Philosophy Department (Phil 479L01/679.06L01, Winter 2004) Richard Zach Course Outline A printable version in PDF format is here Contents Instructor Lectures Course description Prerequisites and Preparation ... Tentative Syllabus and Due Dates Instructor Instructor Richard Zach Office: 1254 SS Email: rzach@ucalgary.ca Phone: Office Hours: TuTh 12:30-1:15 Lectures Lectures 129 Science A Course Description Prerequisites and Preparation Logic II (PHIL 379) is a prerequisite for this course. Required Text George S. Boolos, John P. Burgess, Richard C. Jeffrey, Computability and Logic , 4th edition, Cambridge University Press Available at the University of Calgary Bookstore. Evaluation and course requirements Graduate students must complete 4 homework assignments and a take-home final. Problems will be somewhat harder than those for undergraduate students. On each problem on an assignment and exam you will receive a letter grade reflecting the level of mastery of the material shown by the work you submit. According to the Calendar, letter grades are defined as follows: A B C D F Assignments and Policies Late work and extensions Assignments handed in late will be penalized by the equivalent of one grade point per calendar day. If you turn an assignment in late, you must give it to me personally or put it in the department drop-box (it will then be date-stamped by department staff). Note that the drop-boxes are cleared at 4 pm, the department closes at 4:30 pm on weekdays and is closed Saturdays and Sundays. There will be no make-up exams under normal circumstances; for the final exam, university policies for deferral of exams apply.

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