[Top] [All Lists]

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 18:03:56 -0700
Message-id: <p0623094cc25c1b727e0a@[]>
>Pat,    (01)

<snip>    (02)

>>>such that all the information about that subject can be collocated 
>>>to a single location.
>>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.
>Well, I don't know if it is your "logic-fixation" or simply bad 
>prose on my part but the "all" in that statement referred to all the 
>information on a subject in a topic map. I wasn't claiming and I 
>don't really think you thought I was, that a topic map contains 
>*ALL* the information known about a subject.    (03)

Well, that is a relief. :-)    (04)

>Not real sure how one would make a judgment of that sort anyway.
>As far as the pragmatic purpose, consider the following example. I 
>recently did a paper under contract that compared topic maps and 
>record linkage, a technique that arose in vital records in the late 
>1950's. In doing that research, I discovered that the same technique 
>has been studied under the following names:
>merge/purge, de-duplication, hardening of soft databases, reference 
>matching, object identification, identity uncertainty, entity 
>heterogeneity, entity identification, object isomerism, instance 
>identification, entity reconciliation, list washing, data cleaning, 
>deduplication and co-reference resolution
>I should note that more than one mathematical model has been 
>developed for the technique, apparently due to failure to discover 
>that the work had already been done under another name.
>Gee, you pose a tough question. Why would I possibly want to have 
>information about that particular technique gathered together, 
>without regard to the means used to identify it? Hmmm, well, perhaps 
>so that I would not duplicate research done under another name for 
>the same subject?    (05)

It doesn't need to be in the same place for that, it only needs to be 
accessible. Sitting here in my front room I can access information 
stored in China or Vietnam or Spain.    (06)

>So that I would not have to duplicate the matching that had been 
>done by someone else between one or more of these terms? (Noting 
>that I don't guarantee that a search on any of these terms will 
>*always* return information that is about the same subject as the 
>term "record linkage." Not only do people use different terms but 
>sometimes a single term is used differently by different people.)
>If that sounds too "academic," imagine you are in a hospital 
>emergency room and your physician misses critical information that 
>would have been beneficial but was missed because they did not use 
>the terminology necessary to find it.    (07)

Something very close to this actually happened to my wife (she was 
given an antibiotic to which she is allergic).    (08)

>>>That's it. No attempt to specify a semantic theory or reasoning, etc.
>>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.
>Actually topic maps or at least the behavior that topic maps 
>represent, the mapping of different identifications of the same 
>subject, is far older than Peirce. How do you think people do 
>>Logic does not *require* reasoning; but in any case, deriving the 
>>conclusion that <this>=<that> is a very simple kind of reasoning.
>Oh, part of your logic-fixation again. Yes, you can characterize a 
>mapping of <this>=<that> as simple logic if that makes you feel any 
>better.    (09)

Its not a case of feeling better, but of whether or not this is a 
logical inference; and it is. Quite a lot of OWL applications are 
used almost exclusively to come to conclusions of this form, using 
inverse-functional properties. Quite a lot is known about techniques 
of (reasonably) efficient equality reasoning, which I imagine would 
be directly applicable to your area of concern. I think its you who 
has logic-phobia. :-)    (010)

>>>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.
>>Just as they can in a first-order logical semantic framework.
>Oh, you mean like Peirce did in identifying a thief and the porter 
>who stole his watch as the same person?    (011)

I don't know that anecdote, sorry.    (012)

>But more to the point and what seems to be completely ignored in 
>this discussion, is that most people don't use first-order semantic 
>frameworks to make those mappings.    (013)

Ah, this is the nub of the matter. I reject this claim. True, people 
don't formalize their conclusions to themselves in a classical 
textbook first-order notation; but are they in fact using first-order 
valid inferences? I think in fact they often are. Bear in mind that 
machine inference is not done by using a textbook-style display of a 
linear proof sequence, A following from B by a logical inference 
rule: it is done by heuristic techniques generating a semantic 
tableau, or by a Davis-Putnam process, or the like. But it is still 
first-order inference. And humans reason in ways that seem to be 
almost directly first-order, including when deciding identities. Bill 
was wearing a yellow jacket; very few people wear yellow jackets; the 
only person I can see wearing a yellow jacket is that guy over there; 
that guy is probably Bill. This is a first-order logical inference. 
Or: Joan should be here by now; Joan hasnt phoned; if Joan had known 
she was going to be late she would have phoned; so, something 
unexpected must have delayed her. That is a first-order logical 
inference. And so on, and on. I don't want to claim that *all * human 
reasoning is first-order: but a surprisingly large amount of it seems 
to be.    (014)

>Agreed, such mappings can be made in your first-order semantic 
>framework. So what? Given the limited number of people who use them, 
>how successful are they going to be in generating the number of 
>mappings required?    (015)

I think that any framework which is less expressive than FOL isn't 
going to stand a chance of mirroring the inferences that people 
routinely make, almost every minute they are awake, without 
necessarily being consciously aware of it.    (016)

<snip>    (017)

>>>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.
>>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.
>Just because you are not concerned with a problem, such as finding 
>information (whether networked or not, topic maps are not limited to 
>networked information), doesn't mean that it isn't real or doesn't 
>merit a solution.    (018)

Oh, I entirely agree.    (019)

>That you would suggest very large hash tables shows you haven't 
>devoted much thought to the problem. Hash tables, large or 
>otherwise, are not in and of themselves an answer to the problem of 
>different identifications for the same subject or the same 
>identiification being used by different people for different 
>subjects.    (020)

Of course not. I agree this is an important issue; but topic maps 
simply record this, as far as I can see. To record an equation is 
easy: it can be done in almost any formalism.    (021)

>Moreover, with a topic map I can record my mapping between different 
>identifications for the same subject, which would be a benefit to 
>the next person who searches for that subject under any of its 
>identifications.    (022)

If I follow what you mean here, we also invented a notation for this 
in IKL. Its basically the use of typed literals, where the 'datatype' 
is the identification mapping. But I agree, having a very general 
notation for this is useful.    (023)

So let me see if I understand this. as you explain it. A topic map is 
basically a complex name for a thing, one which records a variety of 
'superficial' names, each used in a different context of 
identification to refer to the same thing. The TM records both the 
fact of these names being coreferents and records, and links to, the 
various contexts of identification where the superficial names are 
used.  So one might express it as a collection of <namestring, 
identification-context> pairs. Is that right?    (024)

>Topic maps are in use by diverse such organizations such as the 
>Norwegian Post Office, the IRS, the Office of Naval Intelligence and 
>the Y-12 Complex at Oak Ridge, as well as the Danish Royal Library. 
>To name only a few.
>Google isn't a solution. It is a symptom of the problem faced by 
>anyone who wants to find information about a subject however it is 
>identitified.*    (025)

It is a vitally important tool, however. And it solves a whole lot of 
problems: the Web wouldn't be nearly so useful without it.    (026)

>*(The SW proposal that every subject have a single unique identifier    (027)

Whoa, that isn't the SW proposal, and its not the TAG Web 
architecture position either. Of course there isn't a single unique 
identifier, in general: if there were, owl:sameAs would be vacuous. I 
agree, the idea of single unique 'true name' is ridiculous. I call it 
the EarthSea theory of reference, after the idea in the Ursula LeGuin 
novels.    (028)

Pat    (029)

IHMC            (850)434 8903 or (650)494 3973   home
40 South Alcaniz St.    (850)202 4416   office
Pensacola                       (850)202 4440   fax
FL 32502                        (850)291 0667    cell
phayesAT-SIGNihmc.us       http://www.ihmc.us/users/phayes    (030)

Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/  
Subscribe/Config: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/  
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/ 
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx    (031)

<Prev in Thread] Current Thread [Next in Thread>