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Re: [ontolog-forum] Can Syntax become Semantic ?

To: "[ontolog-forum] " <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Christopher Menzel <cmenzel@xxxxxxxx>
Date: Fri, 22 Jan 2010 18:35:54 -0600
Message-id: <F4D4F62B-BFD7-4193-A9FA-5247D435132C@xxxxxxxx>
On Jan 22, 2010, at 5:08 PM, Rob Freeman wrote:
> Chris,
> On Sat, Jan 23, 2010 at 8:59 AM, Christopher Menzel <cmenzel@xxxxxxxx> wrote:
>> On Jan 22, 2010, at 3:45 AM, Rob Freeman wrote:
>>> ...It's common these days to blame a lack of general 
>knowledge("background") for our inability to program computers to 
>understandnatural language.
>>> I'm convinced much of the problem is that there is a wealth of detail in 
>syntactic structure which we simply throw away.
>>> This is related to my point that there are many computational processes 
>which cannot be completely summarized.
>> You've not made a point you've only asserted a sentence with no clear 
> I thought John stated it well:
> On Wed, Jan 20, 2010 at 4:57 AM, John F. Sowa <sowa@xxxxxxxxxxx> wrote:
> "For some pairs of (M,T), the predicate Will_Halt can be determined by a 
>proof in FOL. But for others, the theorem prover will loop forever. But any 
>(M,T) that is undecidable in FOL will be just as undecidable in English or any 
>other language, formal or informal."    (01)

Oh, so for some reason you are using your own personal terminology "cannot be 
completely summarized" to mean what everyone else means by "undecidable".  
Hence, you also appear to be using "process" to mean "problem", for it is 
*problems* that are decidable or undecidable.  Notably, John is referring to 
the general *problem* of determining whether an arbitrary Turing machine M that 
is set a-going on arbitrary input T (i.e., what is more commonly called a 
computational "process") will eventually halt.    (02)

So it appears that the content of your claim that "there are many computational 
processes which cannot be completely summarized" is nothing more than the fact 
that there are undecidable computational problems.  What I don't understand is 
why you are using your own idiosyncratic terminology for expressing this 
exceedingly well known and rather elementary fact about the limits of 
computation.  Surely the only effect of doing so is to obfuscate what is 
otherwise entirely clear.    (03)

> Or you could look at Stephen Wolfram's idea of "computational 
>irreducibility". It appears to me to be saying the same thing:
> "The empirical fact is that the world of simple programs contains a
> great diversity of behavior, but, because of undecidability, it is
> impossible to predict what they will do before essentially running
> them. The idea demonstrates that there are occurrences where theory's
> predictions are effectively not possible."
> (http://en.wikipedia.org/wiki/Computational_irreducibility.)    (04)

Yes, although he appears to be citing undecidability to illustrate a more 
general claim about the predictive limitations of theories.    (05)

Chris Menzel    (06)

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