Bruno Marchal wrote:
> On 22 Aug 2012, at 00:26, benjayk wrote:
>> meekerdb wrote:
>>> On 8/21/2012 2:52 PM, benjayk wrote:
>>>> meekerdb wrote:
>>>>> On 8/21/2012 2:24 PM, benjayk wrote:
>>>>>> meekerdb wrote:
>>>>>>> "This sentence cannot be confirmed to be true by a human being."
>>>>>>> The Computer
>>>>>> He might be right in saying that (See my response to Saibal).
>>>>>> But it can't confirm it as well (how could it, since we as  
>>>>>> humans can't
>>>>>> confirm it and what he knows about us derives from what we  
>>>>>> program into
>>>>>> it?). So still, it is less capable than a human.
>>>>> I know it by simple logic - in which I have observed humans to be
>>>>> relatively slow and
>>>>> error prone.
>>>>> regards, The Computer
>>>>  Well, that is you imagining to be a computer. But program an actual
>>>> computer that concludes this without it being hard-coded into it.  
>>>> All it
>>>> could do is repeat the opinion you feed it, or disagree with you,
>>>> depending
>>>> on how you program it.
>>>> There is nothing computational that suggest that the statement is  
>>>> true or
>>>> false. Or if it you believe it is, please attempt to show how.
>>>> In fact there is a better formulation of the problem: 'The truth- 
>>>> value of
>>>> this statement is not computable.'.
>>>> It is true, but this can't be computed, so obviously no computer can
>>>> reach
>>>> this conclusion without it being fed to it via input (which is  
>>>> something
>>>> external to the computer). Yet we can see that it is true.
>>> Not really.  You're equivocating on "computable" as "what can be  
>>> computed"
>>> and "what a
>>> computer does".  You're supposing that a computer cannot have the
>>> reflexive inference
>>> capability to "see" that the statement is true.
>> No, I don't supppose that it does. It results from the fact that we  
>> get a
>> contradiction if the computer could see that the statement is true  
>> (since it
>> had to compute it, which is all it can do).
> A computer can do much more than computing. It can do proving,  
> defining, inductive inference (guessing), and many other things. You  
> might say that all this is, at some lower level, still computation,  

Sorry, but the opposite is the case. To say that computers do proving,
defining, guessing is a confusion of level, since these are interpretation
of computations, or are represented using computations, not the computations
itself. If we encode a proof using numbers, then this is not the proof
itself, but its representation in numbers. Just as "Gödel's proof" is not
Gödel's proof just because I say it represents Gödel's proof.
Or just as I say computers the word computers don't compute anything.

Imagine a computer without an output. Now, if we look at what the computer
is doing, we can not infer what it is actually doing in terms of high-level
activity, because this is just defined at the output/input. For example, no
video exists in the computer - the data of the video could be other data as
well. We would indeed just find computation.
At the level of the chip, notions like definition, proving, inductive
interference don't exist. And if we believe the church-turing thesis, they
can't exist in any computation (since all are equivalent to a computation of
a turing computer, which doesn't have those notions), they would be merely
labels that we use in our programming language.

That is the reason that I don't buy turings thesis, because it intends to
reduce all computation to a turing machine just because it can be
represented using computation. But ultimately a simple machine can't compute
the same as a complex one, because we need a next layer to interpret the
simple computations as complex ones (which is possible). That is, assembler
isn't as powerful as C++, because we need additional layers to retrieve the
same information from the output of the assembler.

You are right that we can confuse the levels in some way, basically because
there is no way to actually completely seperate them. But in this case we
can also confuse all symbols and definitions, in effect deconstructing
language. So as long as we rely on precise, non-poetic language it is wise
to seperate levels.

Bruno Marchal wrote:
> but then this can be said for us too, and that would be a confusion of  
> level.
Only if we assume we are computational. I don't.

Bruno Marchal wrote:
>  The fact that a computer is universal for computation does not  
> imply logically that a computer can do only computations. You could  
> say that a brain can only do electrical spiking, or that molecules can  
> only do electron sharing.
You have a point here. Physical computers must do more then computation,
because they must convert abstract information into physical signals (which
don't exist at the level of computation).
But if we really are talking about the abstract aspect of computers, I think
my point is still valid. It can only do computations, because all we defined
it as is in terms of computationl.


View this message in context:
Sent from the Everything List mailing list archive at

You received this message because you are subscribed to the Google Groups 
"Everything List" group.
To post to this group, send email to
To unsubscribe from this group, send email to
For more options, visit this group at

Reply via email to