To: | "[ontolog-forum]" <ontolog-forum@xxxxxxxxxxxxxxxx> |
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From: | Jawit Kien <jawit.kien@xxxxxxxxx> |
Date: | Wed, 3 Jun 2009 15:21:26 -0500 |
Message-id: | <9f9644bb0906031321p7ddc08ddk1f4990b8165dc6d@xxxxxxxxxxxxxx> |
On Tue, Jun 2, 2009 at 3:41 PM, Jawit Kien <jawit.kien@xxxxxxxxx> wrote:Is there a mailing list where discussions about IKL occur? Chris Menzel said: > Questions/comments about IKL can be directed to the Common Logic > mailing list (since it is an extension of CLIF). I have attempted to subscribe to that list using the form at http://philebus.tamu.edu/mailman/listinfo/cl but have not been subscribed yet to find out if the members of the mailing list agree with Chris Menzel. As I can't send discussions to that list, and don't KNOW that the list is even appropriate, would there be any objections to asking such questions here? I will start out with one question, and if there is an objection to discussion here, we can take it off the ontolog list. If there is an active desire to discuss such questions, but not on the ontolog list and the CL mailin list objects as well, I can create such a mailing list and we can move the discussion there. === My Question === I wasl looking at John Sowa's Upper Level document at http://www.jfsowa.com/ontology/toplevel.htm The issue I have the question about is based on these paragraphs: There is a description of one of his primitive categories. Note his definition of a primitive category is a category of an ontology that cannot be defined in terms of other categories in the same ontology. An example of a primitive is the concept type Point in Euclid's geometry. The meaning of a primitive is not determined by a closed-form definition, but by axioms that specify how it is related to other primitives. A category that is primitive in one ontology might not be primitive in a refinement of that ontology.(from http://www.jfsowa.com/ontology/gloss.htm#Primitive)
this definition implicitly says that a predicate "has" exists, but that it is a "partial function" in the Scott-Strachey denotational semantics meaning. My question is based on defining such a predicate using IKL. To my knowledge, you don't actually have a "define" statement in IKL, you just create some true statements that exist in the specialized logic that IKL defines, and magico-magico, that predicate is available to any other logical statement that uses that predicate. I think John Sowa once called this Quine's web of belief. I can add this primitive category for Independent to some a specialization/generalization hierarchy, but that is not creating an ontology. That is just taking the vocabulary word "Independent" and adding it to a taxonomy. An ontology requires axioms attached to those taxonomic entries. The equation John Sowa gives is has a modal logic "box" which I understand as "necessary". Using Michael Dunn's semantics for modal logic (using laws and facts instead of possible worlds) means that "necessary" conditions can just be logical statements that are in the "Laws". I seem to recall there was an argument that the statements have to be metalanguage logical statements instead of just logical statements, but I think IKL has a way to allow your logic to have metalogical statements. In reflecting, the case of this equation, I think what I actually want to model is "possibility" since I seem to recall from class that (not necessary)Proposition is logically equivalent to (possible)Proposition. So it means the has(x,y) or has(y,x) is in the "Facts" part of Dunn's semantics. But I still don't know how to say that in IKL either. I don't see anything in the guide at http://nrrc.mitre.org/NRRC/Docs_Data/ikris/IKL_guide.pdf to tell me how to do this modeling. (of modal operators "box"(necessity) and "diamond"(possiblity). I do find the two paragraphs which do imply that it is possible to do it: Although it provides for the _expression_ of contextual and time-dependent propositions, IKL is not a context or temporal or modal logic, since such logics are inherently indexical. Sentences of IKL should not be understood to be asserted 'in' an implicit context or belief framework, or 'at' a time of utterance. All such relativizations of assertion or truth must be de-indexed in IKL by referring explicitly to the context, belief state, time-interval, etc.., relative to which they are intended to be understood. Modal and context logics differ from IKL by being inherently indexical, so that even a simple (or unmarked) sentence – one stated without using modalities or context references in its syntax, so it looks just like an IKL sentence – is always understood to be asserted in an implicit 'local' context or setting. So that is my question. How do I state a logical statement that says that another statement might exist or might not? I think once I add a logical statement to a theory, it is true in the theory. But "not necessary" statements may or may not exist. Stated that I way, I don't know if my question is about implementation, logic, ontologies or some other topic that I don't understand very well. Can anyone help me? JK _________________________________________________________________ Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/ Config Subscr: 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 join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (01) |
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