gimel Posted June 17, 2010 Posted June 17, 2010 it is argued by colin leslie dean that no matter how faultless godels logic is Godels incompleteness theorem are invalid ie illegitimate for 5 reasons: he uses the axiom of reducibility- which is invalid ie illegitimate,he constructs impredicative statement which is invalid ie illegitimate ,he cant tell us what makes a mathematic statement true, he falls into two self-contradictions,he ends in three paradoxes http://www.scribd.com/doc/32970323/Godels-incompleteness-theorem-inva... http://gamahucherpress.yellowgum.com/gamahucher_press_catalogue.htm http://gamahucherpress.yellowgum.com/books/philosophy/GODEL5.pdf First of the two self-contradictions Godels first theorem ends in paradox –due to his construction ofimpredicative statement Now the syntactic version of Godels first completeness theorem reads Proposition VI: To every ω-consistent recursive class c of formulae there correspond recursive class-signs r, such that neither v Gen r nor Neg (v Gen r) belongs to Flg© (where v is the free variable of r). But when this is put into plain words we get http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems Gödel's first incompleteness theorem states that: Any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. In particular, for any consistent, effectively generated formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true,[1] but not provable in the theory (Kleene 1967, p. 250). Now truth in mathematics was considered to be if a statement can be proven then it is true Ie truth is equated with provability http://en.wikipedia.org/wiki/Truth#Truth_in_mathematics ”…from at least the time of Hilbert's program at the turn of the twentieth century to the proof of Gödel's theorem and the development of the Church-Turing thesis in the early part of that century, true statements in mathematics were generally assumed to be those statements which are provable in a formal axiomatic system. The works of Kurt Gödel, Alan Turing, and others shook this assumption, with the development of statements that are true but cannot be proven within the system” http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems “Any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. In particular, for any consistent, effectively generated formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true,[1] but not provable in the theory (Kleene 1967, p. 250) For each consistent formal theory T having the required small amount of number theory … provability-within-the-theory-T is not the same as truth; the theory T is incomplete.” Now it is said godel PROVED "there are true mathematical statements which cant be proven" in other words truth does not equate with proof. if that theorem is true then his theorem is false PROOF for if the theorem is true then truth does equate with proof- as he has given proof of a true statement but his theorem says truth does not equate with proof. thus a paradox THIS WHAT COMES OF USING IMPREDICATIVE STATEMENTS GODEL CAN NOT TELL US WHAT MAKES A STATEMENT TRUE GODEL CAN NOT TELL US WHAT MAKES A STATEMENT TRUE Now truth in mathematics was considered to be if a statement can be proven then it is true Ie truth was s equated with provability http://en.wikipedia.org/wiki/Truth#Truth_in_mathematics ”…from at least the time of Hilbert's program at the turn of the twentieth century to the proof of Gödel's theorem and the development of the Church-Turing thesis in the early part of that century, true statements in mathematics were generally assumed to be those statements which are provable in a formal axiomatic system. The works of Kurt Gödel, Alan Turing, and others shook this assumption, with the development of statements that are true but cannot be proven within the system” Now the syntactic version of Godels first completeness theorem reads Proposition VI: To every ω-consistent recursive class c of formulae there correspond recursive class-signs r, such that neither v Gen r nor Neg (v Gen r) belongs to Flg© (where v is the free variable of r). But when this is put into plain words we get http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems “Any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. In particular, for any consistent, effectively generated formal theory that proves certain basic arithmetic truths, there is an arithmetical statement that is true,[1] but not provable in the theory (Kleene 1967, p. 250) For each consistent formal theory T having the required small amount of number theory … provability-within-the-theory-T is not the same as truth; the theory T is incomplete.” In other words there are true mathematical statements which cant be proven But the fact is Godel cant tell us what makes a mathematical statement true thus his theorem is meaningless Ie if Godels theorem said there were gibbly statements that cant be proven But if godel cant tell us what a gibbly statement was then we would say his theorem was meaningless Now at the time godel wrote his theorem he had no idea of what truth was as peter smith the Cambridge expert on Godel admitts http://groups.google.com/group/sci.logi ... 12ee69f0a8 Quote: Gödel didn't rely on the notion of truth but truth is central to his theorem as peter smith kindly tellls us http://assets.cambridge.org/97805218...40_excerpt.pdf Quote: Godel did is find a general method that enabled him to take any theory T strong enough to capture a modest amount of basic arithmetic and construct a corresponding arithmetical sentence GT which encodes the claim ‘The sentence GT itself is unprovable in theory T’. So G T is true if and only if T can’t prove it If we can locate GT , a Godel sentence for our favourite nicely ax- iomatized theory of arithmetic T, and can argue that G T is true-but-unprovable, and godels theorem is http://en.wikipedia.org/wiki/G%C3%B6del%27s_incompleteness_theorems Quote: Gödel's first incompleteness theorem, perhaps the single most celebrated result in mathematical logic, states that: For any consistent formal, recursively enumerable theory that proves basic arithmetical truths, an arithmetical statement that is true, but not provable in the theory, can be constructed.1 That is, any effectively generated theory capable of expressing elementary arithmetic cannot be both consistent and complete. you see godel referes to true statement but Gödel didn't rely on the notion of truth now because Gödel didn't rely on the notion of truth he cant tell us what true statements are thus his theorem is meaningless
ajb Posted June 17, 2010 Posted June 17, 2010 A theorem is only as good as "what is put into it". I believe there are systems for which the incompleteness theorems do not apply. In particular the theorems only really make statements about number theory and arithmetic. Not all of mathematics. I am very ignorant of logic and related things, maybe someone else can say more.
Boberto Posted June 22, 2010 Posted June 22, 2010 Yes, Godel's proof does assert that truth and proof are not equivalent, however proven theorems are still a subset of true theorems. In other words, all theorems that can be proven are true, but not all true theorems can be proven. Similarly, all squares are rectangles, but not all rectangles are squares.
vuquta Posted August 1, 2010 Posted August 1, 2010 In other words there are true mathematical statements which cantbe proven But the fact is Godel cant tell us what makes a mathematical statement true thus his theorem is meaningless Ie if Godels theorem said there were gibbly statements that cant be proven A statement is true if there is an assignment from some given universe that satisifies it. A statement has a very precise definition based on terms and connectives. Here is a statement x² = 2. Here is one with connectives. (x² = 4) ↔ ( x = 2 ) v ( x = -2 ) The first statement is true only if your universe contains the irrational numbers. Thus, the set of rational numbers does not satisify the first statement and so that statement is not true using only the rational numbers. Note how this has noithing to do with proof. The second statement is satisfied (true) by a universe that contains 2, -2 4. A proof is a sequence of operations based on the rules of the first order predicate calculus. So, truth depends on the universe you have and a proof is a syntactic sequence of operations that can be performed by a computer. Godels completeness theorems and incompleteness theorems demarcated the two concepts of proof and truth.
wright496 Posted September 12, 2010 Posted September 12, 2010 it is argued by colin leslie dean that no matter how faultless godels logic is Godels incompleteness theorem are invalid ie illegitimate for 5 reasons: This is all logic. If his theorem isn't valid then his logic MUST be flawed on some level.
vuquta Posted September 12, 2010 Posted September 12, 2010 it is argued by colin leslie dean that no matter how faultless godels logic is Godels incompleteness theorem are invalid ie illegitimate for 5 reasons: This is all logic. If his theorem isn't valid then his logic MUST be flawed on some level. So, what are these 5 reasons? it is argued by colin leslie dean that no matter how faultless godels logic is Godels incompleteness theorem are invalid ie illegitimate for 5 reasons: This is all logic. If his theorem isn't valid then his logic MUST be flawed on some level. http://gamahucherpress.yellowgum.com/books/philosophy/GODEL5.pdf Here above is a link to this crackpot. 1) "For example Godels uses the axiom of reducibility but this axiom was rejected as being invalid by Russell," http://en.wikipedia.org/wiki/Axiom_of_reducibility "The axiom of reducibility was introduced by Bertrand Russell as part of his ramified theory of types, an attempt to ground mathematics in first-order logic" This axiom is required to avoid the liar's paradox. In ZF set theory, this is implemented in the Axiom schema of replacement: http://en.wikipedia.org/wiki/Zermelo%E2%80%93Fraenkel_set_theory Upon further reading, he does not understand that Godel used a meta language for his proof and a godel numbering systen based on Peano arithmatic to code 1st order logic statements satisified by the Natural numbers. Godel was able to prove with Godel numbers, http://en.wikipedia.org/wiki/G%C3%B6del_number that each time you have a set of axioms satisified by the natural numbers, there exists a sentence than cannot be proven to be true by the existing axioms thus far using the first order predicate logic. Whence, the theory of natural numbers cannot be completed using axioms. Tarski then proved his truth theorem/ undefinability theorem to prove that truth in the natural numbers cannot be axiomitized. This implies it is impossible to provide a recipe book for even something as primitive as the natural numbers. Bell and Machover noted this implies science cannot be axiomitized if the natural numbers cannot be axiomitized since science contains the natural number at least. Now you know the rest of the story.
khaled Posted January 19, 2011 Posted January 19, 2011 What if his theorems were based on incompleteness ..?
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