[crm-sig] Scope Note of E77, E2

martin martin at ics.forth.gr
Mon Sep 16 19:15:15 EEST 2002


Dear All,

Following the decision in Copenhagen, here my proposal:

E2 Temporal Entity

Subclass of:   	CRM Entity
Superclass of: 	Condition State
                       	Period

Scope note:    This is an abstract entity and has no examples. It groups
                together transient phenomena such as events, states and others,
                which are limited in time, also called perdurants. It is specialized
                into Period, which holds on some geographic area, and Condition State,
                which holds for, on, or over a certain object. Even though Persitent
                Items (or endurants) have a limited existence in time, because they may
                be destroyed, lost or forgotten, we regard them as disjoint from
                Temporal Enties, as their persistent identity allows to
                relate Temporal Entities in which they participate.

E77 Persistent Item

Subclass of: 	CRM Entity
Superclass of:	Stuff
Contact Point
Appellation
Actor

Scope note:	E77 Persistent Item encompasses (and thereby isolates) entities
                 which share two attributes: having the potential to exist over a
		period of time, and having persistent identity during this period
		of existence. These attributes are intended to apply to both
		concrete objects, whether animate or inanimate and to ideas or concepts.
		Hypothetical or imaginary objects fall within this category insofar
		as they can be considered as conceptual objects i.e. E77 Persistent Item
		is not intended to be restricted to physical existence. Persistent Items
                 are also called endurants.

		The conditions under which an object can be deemed to maintain
		its identity are often difficult to establish - the decision depends
		largely on the judgement of the observer. Most people would agree,
		for example, that a building ceases to exist if it is dismantled
		and the materials reused in a different configuration. Human beings,
		on the other hand, in common with many other organisms, go through
		radical and profound changes during their life-span, affecting both
		material composition and form, yet preserve their identity. But
		also material objects in daily use also undergo material changes
		due to maintenance etc. without changing identity. Identity in
		these cases would seem to depend more on continuity rather than
		the presence of any particular physical state or component.

		The main classes of objects which fall outside the scope of
		E77 Persistent Item are Temporal Entities such as periods, events and
		acts, and descriptive properties, (such as dimensions) which function
		as adjectives and adverbs. The latter depend in there identity
                 on the object they are assigned to. The former acquire an identity
                 only through the changes participating Persistent Items undergo, but not
                 out of their own form or substance. We regard them as disjoint from
		Temporal Entities.

As there are endless debates about the temporal nature of objects,
(so-called 3-dimensionalists and 4-dimensionalists), I propose not to waste
our precious time in the next meeting to discuss, to which degree we can find
logical terms to separate E2 and E77. For me, this is hopeless from the beginning,
and not helpful.

I have never seen a reasonable documentation structure, that puts
objects under events because of their limited life-span. Nor have I seen someone
saying that an event "participates" or is "present at". The evidence in data structures
is that they are disjoint.

Scope Notes are no logical formulas. They remind us our common concepts.
In that spirit, I have deleted the phrase about "persistent identity of
temporal entities", which was, I believe a misinterpretation of "persistent"
in Persistent Item. The "persistence" is, that we can find it again and say
"I have seen that before". For an Event you would say: "Oh, it's still going
on".

So, please make all proposals for this "hot" scope note BEFORE the meeting.

Cheers,

Martin

-- 

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  Dr. Martin Doerr              |  Vox:+30(810)391625         |
  Principle Researcher          |  Fax:+30(810)391609         |
  Project Leader SIS            |  Email: martin at ics.forth.gr |
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                Information Systems Laboratory                |
                 Institute of Computer Science                |
    Foundation for Research and Technology - Hellas (FORTH)   |
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