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Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic)

From André G. Isaak <agisaak@gm.invalid>
Newsgroups comp.theory, comp.ai.philosophy, comp.ai.nat-lang, sci.lang.semantics
Subject Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic)
Date 2020-07-02 23:24 -0600
Organization Christians and Atheists United Against Creeping Agnosticism
Message-ID <rdmfen$m8a$1@dont-email.me> (permalink)
References (1 earlier) <rdle1p$haf$1@dont-email.me> <MLCdnSmK2a-RoGPDnZ2dnUU7-dfNnZ2d@giganews.com> <DrKdnSFFdoqZ2WPDnZ2dnUU7-R_NnZ2d@giganews.com> <rdlleq$tee$1@dont-email.me> <Xu6dnS2UHtvbwWPDnZ2dnUU7-RudnZ2d@giganews.com>

Cross-posted to 4 groups.

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On 2020-07-02 16:14, olcott wrote:
> On 7/2/2020 5:00 PM, André G. Isaak wrote:
>> On 2020-07-02 14:31, olcott wrote:
>>> On 7/2/2020 3:01 PM, olcott wrote:
>>>> On 7/2/2020 2:54 PM, André G. Isaak wrote:
>>>>> On 2020-07-02 13:19, olcott wrote:
>>>>>> The definition of incompleteness:A theory T is incomplete if and 
>>>>>> only if there is some sentence φ such that (T ⊬ φ) and (T ⊬ ¬φ).
>>>>>>
>>>>>> Violates valid/sound deductive inference model:
>>>>>> ∀F ∈ Formal_Systems ∀C ∈ WFF(F) ((F ⊢ C)  ↔ True(F, C))
>>>>>> ∀F ∈ Formal_Systems ∀C ∈ WFF(F) ((F ⊢ ¬C) ↔ False(F, C))
>>>>>> ∀F ∈ Formal_Systems ∀C ∈ WFF(F) ((F ⊬ C)  ↔ NonSequitur(F, C))
>>>>>
>>>>> As far as I can tell, that entails that if some φ can be proven to 
>>>>> be false but cannot be proven to be true, then it is both false and 
>>>>> a non-sequitur.
>>>>>
>>>>> So what is the difference between the two?
>>>>>
>>>>> André
>>>>>
>>>>
>>>> Ah you got me. I did not encode it the way that I usually do:
>>>> ∀F ∈ Formal_Systems ∀C ∈ WFF(F)
>>>> (((F ⊬ C) ∧ (F ⊬ ¬C)) ↔ NonSequitur(F, C))
>>>
>>> Let's try all that using the formal system of Simple_Arithmetic (SA)
>>
>> Unless you actually define what you mean by Simple_Arithmetic, the 
>> below is entirely meaningless.
>>
>> André
>>
>>> A := "2 + 3 = 5" (SA ⊢ A)(true)  (SA ⊢ ¬A)(false)
>>> B := "2 + 3 = 9" (SA ⊢ A)(false) (SA ⊢ ¬A)(true)
>>> B := "2 # 3 = 9" (SA ⊢ A)(false) (SA ⊢ ¬A)(false)
>>>
>>> Since Simple_Arithmetic cannot express self-contradictory sentences 
>>> the only finite strings that cannot be proved or disproved in the 
>>> system are strings that are not WFF.
>>>
> 
> I have a whole C++ program for people that disingenuously claim that 
> they can't begin to understand that "2 + 3 = 5" is true "2 + 3 = 9" is 
> false and "2 # 3 = 9" is gibberish.

That C++ program is a computer program, not a formal system. It is 
possible that it instantiates some formal system called SA, but unless 
you actually provide us with such a formal system we'll never know.

If I were to attempt to guess what SA is supposed to be based on this 
program, all I can come up with is some system which doesn't satisfy the 
conditions which Gödel sets out in his proof. Gödel's theorem only 
applies to formal systems in which a certain minimal amount of 
arithmetic can be performed and, AFAICT, your SA doesn't come close to 
meeting that minimal threshold. Ergo, it is entirely irrelevant to any 
discussion of Gödel.

<snip pointless program>

André

-- 
To email remove 'invalid' & replace 'gm' with well known Google mail 
service.

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Thread

Simply defining Gödel Incompleteness and Tarski Undefinability away V20 olcott <NoOne@NoWhere.com> - 2020-07-02 14:19 -0500
  Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 André G. Isaak <agisaak@gm.invalid> - 2020-07-02 13:54 -0600
    Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 olcott <NoOne@NoWhere.com> - 2020-07-02 15:01 -0500
      Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 André G. Isaak <agisaak@gm.invalid> - 2020-07-02 14:28 -0600
        Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-02 16:01 -0500
        Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 olcott <NoOne@NoWhere.com> - 2020-07-02 16:50 -0500
          Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 olcott <NoOne@NoWhere.com> - 2020-07-02 17:10 -0500
      Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-02 15:31 -0500
        Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-02 15:56 -0500
        Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) André G. Isaak <agisaak@gm.invalid> - 2020-07-02 16:00 -0600
          Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-02 17:14 -0500
            Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-07-02 18:41 -0700
              Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-02 21:03 -0500
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2020-07-02 21:17 -0700
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-03 00:33 -0500
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) André G. Isaak <agisaak@gm.invalid> - 2020-07-02 23:10 -0600
            Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) André G. Isaak <agisaak@gm.invalid> - 2020-07-02 23:24 -0600
              Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-03 01:00 -0500
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) André G. Isaak <agisaak@gm.invalid> - 2020-07-03 01:02 -0600
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) olcott <NoOne@NoWhere.com> - 2020-07-03 12:56 -0500
                Re: Simply defining Gödel Incompleteness and Tarski Undefinability away V20 (Simple_Arithmetic) André G. Isaak <agisaak@gm.invalid> - 2020-07-03 12:17 -0600

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