On Thu, Dec 20, 2012 at 6:32 PM, John F Sowa <sowa@xxxxxxxxxxx> wrote:
Michael and Alan,
MFU
> There is a broader issue here that reasoners are only a part of. That is:
> "Where do you derive confidence from that your ontology is accurate"?
Accuracy is important, but it's only one of many features that make
an ontology good. Sometimes, *less* accuracy is better.
For example, relativity and quantum mechanics are known to be
more accurate than Newtonian mechanics. But Newtonian mechanics
is preferable for large objects moving at typical speeds on earth.
As another example, the Navier-Stokes equations for fluid mechanics
are accurate, but too complex for efficient computation. Therefore,
nearly every application uses some approximations. Sometimes, the
*same* application may use *contradictory* approximations for
different aspects: laminar flow, turbulent flow, subsonic flow,
supersonic flow.
MFU
> There is a nice tool called Ontology Pitfall Scanner which allows
> you to upload an ontology and it will do a bunch of things like this.
I checked the web site, and I noticed that many of the tests it performs
can also be determined by the FCA tools (Formal Concept Analysis). But
FCA can also *generate* the hierarchy automatically in form that is
guaranteed to avoid those pitfalls.
MFU
> Still other ways to derive confidence that the ontology is accurate
> is to have it checked by experts in the field.
Yes. That is a good example of how one should appeal to "authority".
See my further comments on that point below.
But first, I'd like to cite Alan Rector's points on another thread:
AR
> Ambitions for global "reference terminologies" lead to artefacts built
> by committees some of whose originators - e.g. IHTSDO/SNOMED CT -
> even disclaim responsibility for how they should be used...
>
> Large scale reference ontologies - or models of any kind - can also
> be caught by conflicts of requirements from multiple potential users
> - clinical care, statistical reporting, billing, speed of use, etc.
>
> The results have not always been happy.
These are examples of "too many authorities spoil the broth".
JFS
>> Jim [Hendler] said that he liked the article very much:
MFU
> Hmm, the subtext here is scarily close to the fallacy of appealing
> to authority. If Jim liked it it must be good.
I cited Jim in self defense. He is known to be one of the chief
promoters of the Semantic Web, but I've been known to criticize
many aspects of it.
In any case, citing authority is not, by itself, a fallacy. Every
academic paper cites authorities, and any paper without such citations
is suspect. What is wrong is a *fallacious* appeal to authority:
Linus Pauling was a brilliant physicist.
Linus Pauling said that megadoses of vitamin C are beneficial.
Therefore, megadoses of vitamin C are beneficial.
This reasoning is fallacious for two reasons: (1) being an expert
in physics does not necessarily mean that one is an expert in
medicine; and (2) even among experts in medicine, there is no
consensus that megadoses of vitamin C are beneficial.
Re Semantic Web: Jim Hendler is an acknowledged expert, and he has
been highly supportive of its development. I cited his authority
as evidence that my points are compatible with that development.
John