• Re: Church-Turing and computable functions --- best dialogue ever

    From olcott@[email protected] to sci.logic,comp.theory on Thu Oct 22 08:12:47 2026
    From Newsgroup: comp.theory

    On 10/3/2026 10:24 AM, Python wrote:
    Le 03/10/2026 à 17:06, olcott a écrit :
    On 10/3/2026 9:46 AM, Python wrote:
    OK Peter. Here is my understanding of your argument. I am
    deliberately not rebutting it yet.

    You distinguish two things:

    1. HHH receives DD as a finite string.

    2. HHH may manipulate that finite string only according to finite
    transformation rules corresponding to the operational semantics of C.

    3. You distinguish what HHH can derive from DD in this way from what
    happens when DD is actually called directly from main().

    4. Your claim is that no valid finite sequence of transformations
    performed by HHH on its input DD can derive the behavior of that
    direct execution.

    5. Therefore, requiring HHH to answer according to what DD would do
    when directly executed from main() requires HHH to determine
    something that cannot be obtained by the finite-string
    transformations available to it.

    6. You regard that requirement, rather than anything HHH actually
    computes from its finite input, as the invalid step in the
    conventional halting proof.

    7. Hence your claim is not merely "HHH cannot decide whether DD
    halts." Your stronger claim is that the conventional proof
    illegitimately requires HHH to report a fact about a distinct direct
    execution whose behavior cannot be derived by the permitted finite-
    string transformation process.

    I think that is the distinction you believe I previously missed.

    If any part of 1-7 misrepresents your position, please identify the
    number and correct it.

    If you agree that 1-7 accurately states your argument, then we have
    isolated the disagreement precisely and can examine whether step 4 is
    actually true.

    That is a 100-fold better understanding of my work than
    any other human has ever presented. It even much more
    succinctly presents my view much better than the best LLM.

    Then let's keep those seven points as the agreed description of your position.

    That is useful because it means we no longer have to argue about whether
    I understand what you are claiming.

    And I agree that your actual claim is more subtle than simply saying
    that HHH somehow "solves the halting problem".

    Your claim, as I now understand it, is specifically that the
    conventional diagonal argument asks HHH to report the behavior of a computation distinct from the finite-string computation that HHH can actually derive from its input DD.

    So let's focus entirely on point 4:

       No valid finite sequence of transformations performed
       by HHH on its input DD can derive the behavior of the
       direct execution of DD from main().

    That is now the precise proposition we disagree about.

    And I think we can examine that proposition without misrepresenting your position and without appealing to authority on either side.

    We finally have a sharply defined question.

    typedef int (*ptr)();
    int HHH(ptr P);

    01 int DD()
    02 {
    03 int Halt_Status = HHH(DD);
    04 if (Halt_Status)
    05 HERE: goto HERE;
    06 return Halt_Status;
    07 }
    08
    09 void main()
    10 {
    11 HHH(DD);
    12 }

    Simulation Trace
    Line 11: main() invokes HHH(DD);

    keeps repeating unless aborted
    Line 03: simulated DD() invokes simulated HHH(DD) that simulates DD()

    Simulation invariant
    DD correctly simulated by HHH cannot possibly reach past its own line 03

    Concretely show DD simulated by HHH according to the
    operational semantics of C such that this simulated DD
    reaches its own line 06.
    --
    Copyright 2026 Olcott

    *Succinct refutation of the Halting Theorem* https://github.com/plolcott/x86utm/blob/master/README.md


    The essence of computation is applying finite
    string transformations to finite string inputs
    to derive outputs. // paraphrase of Emil Post

    My 28 year goal has been to make
    "true on the basis of meaning expressed in language"
    reliably computable for the entire body of general knowledge.
    The complete structure of this system is now defined.

    The entire body of knowledge expressed in language is
    comprised of two types of relations between finite strings:
    (a) *Axioms* Expressions of language that are stipulated to be true.

    My system bridges the analytic/synthetic distinction by
    expressly encoding all empirical "atomic facts" in a formal
    language such as CycL of the Cyc project.

    (b) *Inference Rules* Expressions of language that are semantically
    entailed syntactically from (a) and/or (b).
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  • From Python@[email protected] to sci.logic,comp.theory on Thu Oct 22 13:45:43 2026
    From Newsgroup: comp.theory

    Peter,

    You have gone back to a message from October 3, before we spent weeks isolating exactly what is wrong with this argument.

    And now you ask:

    Concretely show DD simulated by HHH according to the
    operational semantics of C such that this simulated DD
    reaches its own line 06.

    Certainly.

    You claim that:

    HHH(DD) returns 0.

    So correctly simulate THAT HHH inside DD:

    03 Halt_Status = HHH(DD);

    The simulated HHH(DD) behaves as you claim HHH(DD) behaves:

    HHH(DD) returns 0.

    Therefore:

    Halt_Status = 0;

    Continue the C operational semantics:

    04 if (Halt_Status)

    becomes:

    if (0)

    so line 05 is skipped and execution reaches:

    06 return Halt_Status;

    DD reaches line 06.

    There. Done.

    Your response will presumably be:

    "But the simulated HHH(DD) does not return 0.
    It recursively simulates DD instead."

    And THAT is exactly the problem we have spent weeks identifying.

    You simultaneously claim:

    actual HHH(DD) returns 0

    while your allegedly correct simulation of:

    HHH(DD)

    does NOT return 0.

    Then your simulation is not simulating the behavior of the HHH you claim
    to have implemented.

    You cannot have both:

    HHH(DD) returns 0

    and:

    a correct simulation of HHH(DD) cannot return 0.

    Pick one.

    If simulated HHH faithfully reproduces your claimed HHH:

    HHH(DD) -> 0
    DD -> line 06
    DD halts
    therefore 0 was wrong.

    If simulated HHH instead recursively expands forever:

    HHH(DD) does not return

    then you have not simulated the terminating HHH(DD) that you claim returns
    0.

    And if you abort that recursive simulation and return 0 only to main, we
    are straight back to the point you refused to answer yesterday:

    you returned 0 to main,
    not to the HHH call inside DD.

    So please do not drag the discussion back to October 3 as though the intervening discussion never happened.

    Your "simulation invariant":

    DD correctly simulated by HHH cannot possibly
    reach past its own line 03

    already assumes the very thing at issue:

    the HHH called at line 03 never returns.

    But your claimed result is:

    HHH(DD) returns 0.

    Those two claims are incompatible if this is genuinely the same HHH
    operating on the same DD.

    That is the contradiction you keep calling a refutation of the Halting Theorem.

    It isn't.

    It is the Halting Theorem biting your implementation.
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  • From dart200@[email protected] to sci.logic,comp.theory on Thu Oct 22 16:24:35 2026
    From Newsgroup: comp.theory

    On 10/22/26 6:45 AM, Python wrote:
    Peter,

    You have gone back to a message from October 3, before we spent weeks isolating exactly what is wrong with this argument.

    And now you ask:

    Concretely show DD simulated by HHH according to the
    operational semantics of C such that this simulated DD
    reaches its own line 06.

    Certainly.

    You claim that:

       HHH(DD) returns 0.

    So correctly simulate THAT HHH inside DD:

       03  Halt_Status = HHH(DD);

    The simulated HHH(DD) behaves as you claim HHH(DD) behaves:

       HHH(DD) returns 0.

    Therefore:

       Halt_Status = 0;

    Continue the C operational semantics:

       04  if (Halt_Status)

    becomes:

       if (0)

    so line 05 is skipped and execution reaches:

       06  return Halt_Status;

    DD reaches line 06.

    There. Done.

    Your response will presumably be:

       "But the simulated HHH(DD) does not return 0.
        It recursively simulates DD instead."

    And THAT is exactly the problem we have spent weeks identifying.

    You simultaneously claim:

       actual HHH(DD) returns 0

    while your allegedly correct simulation of:

       HHH(DD)

    does NOT return 0.

    Then your simulation is not simulating the behavior of the HHH you claim
    to have implemented.

    You cannot have both:

       HHH(DD) returns 0

    and:

       a correct simulation of HHH(DD) cannot return 0.

    Pick one.

    If simulated HHH faithfully reproduces your claimed HHH:

       HHH(DD) -> 0
       DD -> line 06
       DD halts
       therefore 0 was wrong.

    If simulated HHH instead recursively expands forever:

       HHH(DD) does not return

    then you have not simulated the terminating HHH(DD) that you claim
    returns 0.

    And if you abort that recursive simulation and return 0 only to main, we
    are straight back to the point you refused to answer yesterday:

       you returned 0 to main,
       not to the HHH call inside DD.

    So please do not drag the discussion back to October 3 as though the intervening discussion never happened.

    Your "simulation invariant":

       DD correctly simulated by HHH cannot possibly
       reach past its own line 03

    already assumes the very thing at issue:

       the HHH called at line 03 never returns.

    But your claimed result is:

       HHH(DD) returns 0.

    Those two claims are incompatible if this is genuinely the same HHH operating on the same DD.

    you add urself to the endless list of those who have pointed out this particularly egregious incoherency

    That is the contradiction you keep calling a refutation of the Halting Theorem.

    It isn't.

    It is the Halting Theorem biting your implementation.
    --
    arising us out of the computing dark ages,
    please excuse my pseudo-pyscript,
    ~ the lil crank that could

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