On 10/25/23 4:01 PM, olcott wrote:
> On 10/25/2023 5:25 PM, olcott wrote:
>>
https://www.liarparadox.org/Linz_Proof.pdf
>>
>> This Turing Machine description at the top of page 3
>> q0 WM ⊢* Ĥq0 WM WM ⊢* Ĥ ∞
>> q0 WM ⊢* Ĥq0 WM WM ⊢* Ĥ y1 qn y2
>>
>> Is simplified and clarified to this:
>> when Ĥ is applied to ⟨Ĥ⟩
>>
>> Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qy ∞
>> Ĥ.q0 ⟨Ĥ⟩ ⊢* embedded_H ⟨Ĥ⟩ ⟨Ĥ⟩ ⊢* Ĥ.qn
>>
>> The advantage of the Linz proof is that it simultaneously represents
>> the entire infinite set of what would otherwise be an infinite set of
>> H/D pairs by using a single TM template for Ĥ.
>>
>> *We can say that both yes and no are incorrect answers for every*
>> *embedded_H that attempts to answer the question*
>> Does the computation that I am contained within halt?
>
>
> When we accept the idea of a pure function and that computations
> must be pure functions then we know that it would be incorrect
> for H to report on the computation that itself is contained within.
Right, it is impossible to write an input that tries to actually use the
decider that is deciding on it, as such an input would not represent an
actual computation.
Thus, "the input" that the decider needs to decide on is always the
specific input of that problem, built on a specific decider, and that
input thus always has a defined behavior, and thus a correct answer.
Thus we START choosing a decider, and then we can built an input, and
that input WILL have a correct answer, it just is a fact that the
decider doesn't give it.
The fact the actual question, "Does the computation represented by the
input halt?" actually has a correct answer for every possible version of
this problem, means it is a valid question.
The fact that no decider can give the right answer for some particular
input, means that no decider is actually correct, and thus the problme
is uncomputable.
>
> embedded_H cannot even see the computation that itself is contained
> within it can only see the behavior of its actual input.
>
Right, it needs to answer about the computataion specified by the input.
And the fact that the computation specified by the input just happens to
match itself is thus irrelevent to the validity of the question, since
the problem statement is to try to handle ALL inputs, and this input is
a member of the input set.
You keep on trying to make the input dependent on the decider it is run
on, THAT is incorrect. The input is based on the decider that it was
built to prove wrong, and is thus a FIXED input, with an answer.
Your problem seems to be that you want to limit the behavior that H is
required to answer on to be something that it can actually compute.
You try to make Ĥ to not have a "correct" answer, but Ĥ isn't a decider,
so it doesn't need to have any particular answer. It just has defined
behavior, that H needs to correctly predict for *H* to be correct.
H is the machine that needs to have the "correct" behavior to be right,
and that behavior is fixed by the code the defines H.
The fact that we can't possibly write an H that gives the correct answer
to this particular input just means that the question is uncomputable,
not "invalid".