On Dec 24, 2010, at 11:00 PM, Ron Wheeler wrote: On 24/12/2010 7:26 PM, Christopher Menzel wrote: ...As for part (b) of (D), I have to say I am nonplussed. What do you have in mind? Obviously, it is unlikely that any large ontology with be completely free of modeling errors, but surely the usefulness of an ontology is inversely proportional to the extent of its errors.
Given the extensive discussion in this forum about the meaning of some very basic terms and expressions of very common concepts (even ignoring the choice of English words associated with them which causes all kinds of unintended meanings drawn into terms), it is unlikely that any ontology will be devoid of fragments that some very smart people who purport to be "Ontologists" find defective or simply wrongheaded.
That could be true. Or not. Either way, this issue has nothing whatever to do with the points I've argued in this thread. My point entails only that any usable ontology language must be such that there can be no reasonable disagreement about the meanings of its basic *logical* expressions or about such matters as how the meaning of a complex _expression_ of the language is determined by the meanings of its simpler parts. What you are talking about are the *non-logical* terms of an ontology, whose meanings might well be controversial and might well evolve over time.
I never saw any of the heated arguments in this forum prefaced by the statement of either party that the points were incidental and not related to some severe misunderstanding about the nature of the truth and logic on the part of the other person.
I'm afraid I'm not seeing how this comment relates to the preceding, Ron. ... The usefulness of an Ontology will be judged by the ROI that it provides to the user community which in turn will be determined by how it advances the solution of a real world problem.
Sure thing. Again, completely orthogonal to the issues I've raised.
I did not think so but perhaps you are right.
Most ontologies will likely be in a constant state of revision as new concepts and relationships become known and need to be added to the ontology to remove some defect or increase its scope. Think of the medical area or financial services where advances and new products are daily occurrences.
And again. But hey: hear hear.
That does not mean that an ontology is not useful.
Sure thing -- so long as it is written in a language "based on formal logic". ;-)
Is there a commonly accepted list of these languages and any other alternatives that are used but should not be or is this purely an academic statement? If this list does not exist, perhaps this forum is a good group to develop the list and document it so that repository developers should be aware of what needs to be supported for import and export.
Well, I don't know that anyone has actually compiled a list — it would be rather open-ended, for one thing — but it's pretty clear when you've got one. The various OWLs are obvious examples and, hence, also the language of any (well-designed) tool based thereon, e.g., Protege. Any Common Logic dialect is such a language. CycL and most all traditional frame-based KR languages like KL-ONE and its descendants would included. More generally, the languages in question include all those based on (some fragment of, or extension of, or extension of a fragment of) classical first-order logic.**
-chris
**I don't thereby mean to exclude non-classical logics — indeed, some, like intuitionistic logic, can be considered fragments of FOL — although I think the use of such logics is motivated by reasoning issues rather than representation. And I don't mean thereby to suggest those issues are unrelated to representation, but I think they are in any case independent of the issues raised in this thread.
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