Re: [ontolog-forum] The concepts can change?

To:	"'[ontolog-forum] '" <ontolog-forum@xxxxxxxxxxxxxxxx>
From:	"Matthew West" <dr.matthew.west@xxxxxxxxx>
Date:	Sat, 14 Jul 2012 12:09:39 +0100
Message-id:	<50015377.4867b40a.062c.241b@xxxxxxxxxxxxx>

Dear Ali,

Dear Matthew and Marcelino,

In socially constructed domains, it may be the case that it is useful to model a concept with changing definitions through time.

Take for example the medical domain and the definition of a disorder X. In some authoritative medical journal or text at year YYYY, the disorder may be defined as containing certain characteristics. In some future edition of a similar authoritative text, what exactly counts as an X may evolve. It would then be useful / valuable / instructive to scope the definitions of X through time, and in so doing to capture how the different interpretations of X have been applied.

MW: I would consider these separate classes, with something about who defined them and when the definition was in use. A simple example is the update in the specification of some engineered product. The differing definitions are known as versions and variants (depending on whether or not they are concurrent). Here there is a supertype that the versions and variants are subtypes of. Versions would have a successor relationship. Variant is itself a specialization relationship.

Such a scenario is quite common in regulatory and legal domains. A legal concept may be defined (and created) in some article of some legislation and it may be amended at a later date. Arguably, you could model this evolution as two distinct concepts, related by an amending action, though colloquially, the notion of say, "Tax Payer" would remain constant. Modeling the changing definitions of "Tax Payer" is definitely of use to the intended consumer of said legal concepts and from their point of view, there is only one concept under consideration.

MW: This would fit quite well with the version and variant models. So Corporate Tax Payer and Private Tax Payer would be variants, and each of these might have versions over time. They are still just different classes though with dates that determine when they apply.

In such a scenario, the concept of "Tax Payer" was created for a given jurisdiction due to a particular article / section of law, and the meaning of this term may change according to other pieces of legislation (or court decisions) as issued by the relevant legislative authorities in said jurisdiction. Should this jurisdiction (or geo-political entity) cease to exist, the concept of "Tax Payer" may consequently also cease to exist.

MW: Indeed, and jurisdiction would be another basis for having other variants and versions, with a jurisdiction giving you a coincident set of variants and versions.

Regards

Matthew West

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Best,

Ali

On Sat, Jul 14, 2012 at 10:47 AM, Matthew West <dr.matthew.west@xxxxxxxxx> wrote:

Dear Marcelino,

What does it mean to say that concepts can change?

MW: For a concept to be able to change would suggest a very unusual usage of the term. Usually the whole idea of a concept is that it refers to the same thing always.

It is the case that the meaning of the concepts can change over time? In this case, what is the meaning of meaning? How one can to trace the identity of concepts over time, in order to judge that a (same) concept was changed? What remains the same when occur a change in a concept?

MW: These would be excellent questions to ask anyone who suggests that concepts can change.

Or it is the case that each meaning is related to a single concept? In this perspective, seems that when we say that a concept was changed, in truth, we have two concepts: the previous concept and a new concept (with a new meaning).

MW: This would be the usual usage.

Does it make sense to say that a concept can cease to exists?

MW: That depends on how you are using the word “concept”. If you are using it as a synonym for class then it probably does not make sense. But one of the usages of concept has it as the representation of some thing in some particular human brain, in which case presumably they cease to exist when the person dies or forgets them.

How these questions are related to the practice of ontology engineering?

MW: They questions you need to get out of the way.