From: rjh@cpax.org.uk
On 09/02/2023 1:09 am, Ben Bacarisse wrote:
> Richard Heathfield writes:
>
>> On 08/02/2023 9:07 pm, Ben Bacarisse wrote:
>>> Richard Heathfield writes:
>>>
>>>> On 08/02/2023 3:03 pm, Paul N wrote:
>>>>> On Tuesday, February 7, 2023 at 9:58:29 PM UTC, JJ wrote:
>>>>>> If you go to any programming sub in Reddit, or any programming channel
in
>>>>>> Discord, you'll realize that some people aren't capable of realizing
that
>>>>>> they are wrong.
>>> Yes, it's a rather quaint idea. Some subjects might make it easier for
>>> people with open minds to discover their mistakes, but it's very far
>>> from being universal!
>>
>> Indeed, although computer programs have proven to be singularly adept at
>> proving their authors wrong!
>
> Yes, that's a good point. Programming is more frequently humbling than
> very many other activities, at least for most of us.
>
>>>>> This is even more obvious in comp.theory. There is a poster there who
>>>>> claims to have refuted the Halting Problem proof,
>>>>
>>>> I refute it too. Bear with me.
>>> OK...
>>
>> Ta.
>>
>>>>> and to have a system which can accurately determine whether a program
>>>>> will halt or not.
>>>>
>>>> I, too, have such a system. Bear with me.
>>> This is a rather different claim. The "Halting Problem proof" surely
>>> refers to a proof of a specific mathematical theorem, so it's not clear
>>> in what way any particular C program refutes it.
>>
>> The refutation is in the program's output (which is always correct):
>>
>> If executed, the specified program will halt.
>>
>> Which it will. ALL programs halt.
>
> Come on! You know I know what that C program does.
Yes, of course.
> What I don't know
> is in what way that C program refutes a mathematical theorem. One makes
> statement about programs,
Yes. That statement refutes the mathematical theorem by pointing
out an obvious fact about all programs.
> the other makes statements are Turing
> machines. Presumably you don't think Turing machines all halt in the
> same sense that you think all programs halt?
Of course all Turing machines halt. You don't seriously think it
is possible for a Turing machine *not* to halt, do you?
>
>>>>> He has a demonstration program, which he claims does not halt
>>> His claims change, but when I last checked in he (the loon in
>>> comp.theory) was still being clear that the program in question halts.
>>> He's posted code, he's posted traces of the simulation, he's stated it
>>> in plain words.
>>>
>>>> He is mistaken.
>>> On this point, no.
>>
>> The specific statement I was addressing was: "He has a demonstration
>> program, which he claims does not halt"
>>
>> Such a claim would be erroneous.
>
> OK. I was addressing his claims in the context of his model of
> computation, not yours. His is abstract, yours is concrete. The
> abstract model is interesting whereas yours is not -- in the technical
> sense of interesting (that has been cut).
I do not demand that you find my claim interesting. False claims
are very often far more interesting than true claims.
>>
>
> Oh, OK.
You sound disappointed. I don't remember what I snipped and I'm
not going to check, but my intent was not to disappoint but to be
briefer.
> I'm old-school. I liked it more when Usenet was informative rather than
> entertaining.
I guess that makes me middle-aged school, because I like both.
> I prefer to learn what people know and think and believe
> about things. I'll try to reply in a more entertaining way in future!
That's your decision, not mine. (But I don't think it's written
down anywhere that information has to be dull.)
--
Richard Heathfield
Email: rjh at cpax dot org dot uk
"Usenet is a strange place" - dmr 29 July 1999
Sig line 4 vacant - apply within
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