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Re: [ontolog-forum] Foundation ontology, CYC, and Mapping

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From: "sean barker" <sean.barker@xxxxxxxxxxxxx>
Date: Thu, 25 Feb 2010 21:57:20 -0000
Message-id: <30E02E43FE414CD08407BF60903B4786@SMB>

 Pat C    (01)

 Actually, what Pat H says is far more interesting (in the bad sense implied 
in the Chinese curse, "may you live in interesting times")    (02)

 In particular, the implication is that, if you don't get the foundational 
ontology right first time, it is useless, because subsequent changes will 
invalidate all that has gone before.    (03)

 If we define a concept C, which is defined using an axiom Q, and replace Q 
with an axiom P such that Q implies P but not vice versa (P is "stronger 
than" Q, then any process that had Q as a post-condition may produce invalid 
answers.    (04)

 If we replace Q with a weaker axiom R, such that R implies Q but not vice 
versa, then any process which uses Q as a precondition can no be used, as 
the preconditions may be violated.    (05)

 That is, if a "primitive concept" can be defined in an FO, then that 
definition must, from the start, say absolutely everying that needs to
 be said about the concept, since any change to the concept will break the 
interoperability that it was intended to support.    (06)

 Sean Barker, Bristol, UK    (07)

 PS The trarditional form of the Limerick is    (08)

 There was a young man of Japan
 Whose Limericks would never quite scan.
 When his friends asked him why,
 He said "It's 'cause I
 Always try and get as many words into the last line as I possibly can".    (09)

> -----Original Message-----
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
> [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Patrick
> Cassidy
> Sent: 25 February 2010 17:19
> To: '[ontolog-forum] '
> Subject: Re: [ontolog-forum] Foundation ontology, CYC, and Mapping
>                    *** WARNING ***
>  This message has originated outside your organisation,
>  either from an external partner or the Global Internet.
>      Keep this in mind if you answer this message.
> John,
>   The disconnect between PatH's view of "meaning" and mine is that he
> is content to believe that the meanings of the elements used in
> programs, databases, ontologies (e.g. time, distance, physical object,
> dollar, person) all change every time we add a new assertion about
> unicorns, and I am not.
> IMNSHO, this is not a useful interpretation of "meaning" for practical
> programming purposes.
>   I am well aware that for each new axiom added to an ontology, some
> logical inferences derived from input assertions will change.  But in my
> view there are some elements - specifically the primitives - whose
> interpretation by programmers, database developers, and domain
> ontologists
> *must* not change when remotely related elements are added, and they
> will still be used in the same way in programs and still give **the same
> answers** to queries that are of practical importance to the programs
> they are used in - even if they may give different answers to bizarre
> test queries that force reasoning to reach the remote parts of the
> ontology that have changed.  Semantic interoperability is a practical
> problem that has been addressed in the past by local agreements on
> interpretation of data elements without resort to Model
> theoretic/Tarskian theories, and the FO is merely a practical tactic to
> extend the ability to forge useful and practical agreements on meaning
> among a much wider community than is possible through local agreements.
> In spite of the admitted beauty and power of model theory, if in fact it
> forces the conclusion that all meanings change when a new axiom is
> added, then it is not a proper formalization of what "meaning" has to
> mean in a computational ontology.
>   One way that the apparent problem might be addressed is to recognize
> that programs have some expected behavior for their data elements, and
> this can be tested with test suites.  If some change to an FO causes a
> change in the usage of data elements that are not intended to be
> changed, then either (1) that change is inconsistent and has to be
> rescinded or somehow modified so that the proper usage of other data
> elements is not affected; or (2) programs that are affected by a change
> in the FO have to use the old FO, and if they need to interoperate with
> programs that use the new FO they will have to take precautions against
> the undesirable changes.
>   But these problems affect interoperability primarily if there are
> changes in the FO.  The problem of changes to the FO is precisely why I
> have suggested that it is important to identify at the earliest stage as
> many as possible of the primitives that will be used for translating
> among multiple domain ontologies. That will keep the need for changes to
> an FO to the minimum that is practical.
>   Another comment from PatH that is puzzling:
>> [PC] > > Perhaps future objections could focus on genuine technical
>> problems
>> > (not analogies with human language), and better yet suggest
>> > alternatives to solving the problem at hand: not just *some* level
>> > of interoperability, but accurate interoperability that would let
>> > people rely on the inferences drawn by the computer.  If not a
>> > common
> FO, then what?
>> [PH] > Nothing. This is not a viable goal to seek. It is a fantasy, a
> dream.
>> One does not seek alternative ways to achieve a fantasy.
>   I had thought that general accurate semantic interoperability (not
> "perfect" interoperability) was the goal of the "Semantic Web", and it
> seems that PatH's comment therefore includes the SW in the realm of
> "fantasy".
> Since PatH is a Semantic Web enthusiast, I doubt that was his intention,
> but it would seem that some clarification is required.
> Pat
> Patrick Cassidy
> MICRA, Inc.
> 908-561-3416
> cell: 908-565-4053
> cassidy@xxxxxxxxx
>> -----Original Message-----
>> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
>> bounces@xxxxxxxxxxxxxxxx] On Behalf Of John F. Sowa
>> Sent: Thursday, February 25, 2010 8:47 AM
>> To: [ontolog-forum]
>> Subject: Re: [ontolog-forum] Foundation ontology, CYC, and Mapping
>> Pat C, Pat H, and Ron,
>> RW> [Pat H's reply to Pat C] does look like some things worth keeping
>>  > for more than the time it takes to read an e-mail and press delete.
>> I agree.  I'd just like to summarize and emphasize a few points.
>> In the following summary, the quoted sentences are by Pat H, and the
>> unquoted sentences are by me.
>>   1. "Tarskian semantics... is a very general theory of meaning, one
>>      that can be applied to a wide range of languages and notations."
>>      Yes indeed.  In fact, *every* theory of formal ontology that
>> anyone
>>      has proposed in the past half century is based on a Tarski-style
>>      semantics.  That includes Cyc, SUMO, BFO, Dolce, etc., etc., etc.
>>      It also includes the semantics for every digital system (hardware
>>      or software) that has ever been designed and built since the
> 1940s
>>      -- including those for which the designers had no idea what a
>>      formal semantics is or might be.
>>   2. "It is just wrong to draw the contrast between the natural
> things,
>>      on the one hand, and the account provided of those things by a
>>      theory of them, on the other, as a difference of **kind**."
>>      Yes.  Every statement in logic is absolutely precise.  The common
>>      words used to define the subject in Longman's dictionary (or any
>>      other dictionary written by lexicographers for human readers) are
>>      usually rather vague and shift their meanings slightly from one
>>      definition to the next.  But that vague cloud of meaning
>> *includes*
>>      the formally defined meaning.  The vague meaning covers more
> cases
>>      and it has a fuzzier boundary, but each precise meaning contained
>>      in the could is just one very sharply defined sense of the same
>>      nature as any other word sense in the cloud.
>>   3. "Computational ontologies are artifacts, written in formal
> logical
>>      notations."
>>      Although I agree with that statement, I suspect that Pat C was
>>      claiming that programs have some meaning other than what is
>>      captured in a formal logic.  But it is important to distinguish
>>      a declarative statement (in a usual logic) from an imperative
>>      statement, such as a command or a machine instruction.  But every
>>      machine instruction and every program written for a digital
>>      computer can be completely defined in the following form:
>>          Preconditions, Action, Postconditions.
>>      The preconditions and postconditions are statements in logic,
>>      which can be formally defined by a Tarski-style semantics.
>>      The preconditions describe the state of the computer system
>>      before the action, which may be a single machine instruction
>>      or an arbitrarily large program composed of many instructions.
>>      And the postconditions define the state after the action.
>>      The action itself has no meaning outside what can be described in
>>      the logic used to state the preconditions and the postconditions.
>>      The human commentary may explain what the programmer or designer
>>      had intended, but if there is any discrepancy between the
> comments
>>      and the program, there is a bug (or *issue* as MSFT calls it).
>> Pat C has repeatedly made the following claim to justify his search
>> for primitives:
>> PC>> So, if we want the meanings of terms in an ontology to remain
>>  >> stable, and **don't** want the meanings to change any time some
>> >> remotely related type appears in a new axiom...
>> PH> But we DO want this! Surely that is the very point of changing
>>  > and adding axioms. If meanings are stable across theories, then  >
>> what is the point of adding axioms to capture more meaning?
>> I'd like to clarify the kind of change that occurs when more axioms
>> are added.  Each addition of an axiom to a theory is a specialization.
>> The change it makes *narrows* the meaning of the terms in it.  For
>> example, the term 'Animal' is very broad.  By adding more qualifiers
>> (axioms), the meaning can be specialized to 'Dog'.  Further axioms can
>> narrow it to 'Poodle'.
>> Those are certainly changes, but they don't go outside the cloud of
>> meaning of the original term.  In fact, every dictionary written for
>> human consumption uses such definitions.
>> John
>>    (010)

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