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Re: [ontolog-forum] Topic maps and the "wheel" of "logical semantics": w

To: patrick@xxxxxxxxxxx
Cc: "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx>
From: Pat Hayes <phayes@xxxxxxx>
Date: Mon, 30 Apr 2007 08:26:57 -0700
Message-id: <p06230947c25bb5abb860@[]>
>No, not much point in continuing this thread. But I did want to 
>point out one statement that is simply wrong and misleading:
>>By the way, the literature of 'Topic Maps' seems to include a kind 
>>of vague groping towards a semantic theory, but it has not yet 
>>reached the level of technical sophistication that logical 
>>semantics reached in the mid-1960s. Sometimes it is a very good 
>>idea to not try to re-invent the wheel, particularly if you don't 
>>know any wheelwrights.
>If that is your impression of topic maps then you are seriously mis-informed.
>Topic maps can be boiled down to two assumptions:
>1. People identify the same subjects differently.
>2. It is possible to disclose a mapping between different 
>identifications of a subject    (01)

The very idea that there is a subject that can be identified in 
various ways is what I meant by my (rather impolite, sorry) term 
'vague groping'. I have read, or tried to read, quite  a lot of the 
Topic Map literature, and it seems clear that Topic Maps are just 
very elementary logic, done in a very peculiar notation and 
terminology. No doubt you will diagnose me as suffering from 
logic-fixation, a disease which causes one to see logic even where it 
is not intended. I will however observe that topic maps have been 
actively promoted as an alternative to RDF, etc., for SWeb use. 
(Which indeed was the only reason I came to study them.) So some of 
their supporters seem to think they have semantic weight.    (02)

>such that all the information about that subject can be collocated 
>to a single location.    (03)

Aside from the above, this seems confused. In general, it is not 
possible to collocate *all* the information about anything in one 
location. Even encyclopedia articles are not *all* the information 
about a thing. All the written biographies of Charles Darwin, say, 
are not *all* the information about him. And even if this were 
possible, why would one want to do this? What engineering or 
pragmatic  purpose would it serve? Pointers were invented so that one 
need not do this.    (04)

>That's it. No attempt to specify a semantic theory or reasoning, etc.    (05)

But that *is* the beginnings of a semantic theory. The first stage of 
any semantics is the mapping between referring expressions and their 
denotations, and the most basic semantic relationship is that of 
identity. Peirce built his whole logic around identity mappings. 
Really, Topic Maps are not anything fundamentally new; they are a 
very old idea wrapped up in a new notation and terminology.    (06)

Logic does not *require* reasoning; but in any case, deriving the 
conclusion that <this>=<that> is a very simple kind of reasoning.    (07)

>Anyone can use any basis for identifying a subject and any basis 
>they like for saying that two or more identifications do indeed 
>represent the same subject.    (08)

Just as they can in a first-order logical semantic framework.    (09)

>That is not to deny that *particular* topic maps may be constructed 
>using particular ontologies or semantic theories. XTM topic maps, 
>for instance, use sets of URIs for subject identification. But that 
>is *a* choice and does not limit (according to the standards as 
>currently written) another topic map from making other choices.
>You can record "logical" properties for subjects if you want to 
>"reason" about them or any other properties that you find useful.    (010)

There is no such thing as a non-logical property.    (011)

>Put a bit more expansively, topic maps are an attempt to enable 
>people who are unaware of the many flavors of ontologies, logic in 
>any form, etc., to get about the business of identifying their 
>subjects as well as recognizing and mapping to other identifications 
>of the same subjects.    (012)

That is a laudable goal, indeed. URNs were created with the same goal.    (013)

>You are free, of course, to use ontologies or logic for such 
>identifications or mappings, but such tools are not required.
>Judging from the current state of finding information on any given 
>subject on the WWW, the wheel of "logical semantics" has been 
>ignored, is broken or has other concerns.    (014)

It has other concerns. Semantics isn't concerned with finding 
information in a network. But I don't seem to find Topic maps of any 
use in this task either. The way to find information is to use a very 
large hash table, such as Google.    (015)

>Hope you are at the start of a great week!    (016)

Ditto.    (017)

Pat    (018)

>Patrick Durusau
>Chair, V1 - Text Processing: Office and Publishing Systems Interface
>Co-Editor, ISO 13250, Topic Maps -- Reference Model
>Member, Text Encoding Initiative Board of Directors, 2003-2005
>Topic Maps: Human, not artificial, intelligence at work!    (019)

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