A theoretical set of questions getting down to some
practical realities…
We have used the phrase “an ontology” and “a
theory” quite a bit – do we really know what these are? Particularly
when we are talking about modular lattices of ontologies/theories we need to
understand the structure and how we manage and use the lattice.
Is “an ontology” and “a theory” the
same?
What does it mean for statements to be in one ontology Vs. Another?
What is the scope of an ontology?
Do ontologies have identity? Do they change over time?
Do statements have idenetity?
Is “an ontology” equivalent to “a file”
of statements?
How big is an ontology? How small can it be?
If it is a lattice, what are the relations between the
nodes? What are the nodes?
From what I can tell, the concept of “an ontology”
has grown out of the practice of representing bits of knowledge in files. The
ontology is a thing you can put in a “file” (Physical or logical).
Perhaps the “semantics” of “an
ontology” is that it is the speech act of a particular person at a
particular time asserting an arbitrary collection of statements. In other
words, there is an act of publishing an ontology or theory. But, there is
no inherent semantics in the bounds or context of that speech act. Any
boundary or “subject” is only in the mind of the publisher.
“A theory” seems a bit stronger in that an
instance can be tested for compliance with that theory. However, the
scope of that theory is still arbitrary and probably corresponds with a speech act,
such as above.
As with any intellectual asset, these things change over
time. There are versions, each with identity and some assumed identity
for a sequence of ontologies. The scope of the ontology will also change
over time – it will usually get larger as the connection points of the
concepts are better understood. Is this one ontology or many? What
is there relationship? How is this managed?
We will need an approach to managing the lattice. We are
concerned that arbitrary chunks of statements in files will not scale.
An approach to this is that statements depend on and are
assertions in a defined set of context. Once such context is publication
(the replacement for the file). There is no such thing as “an
ontology”, there is a way to reason within a given set of context. Based
on the discussions in this group, such reasoning is practical. Can this
lattice “a thing” or can it exist across the semantic web?
So is an ontology anything more than an arbitrary set of
statements? Is it more or less than a file? Does it exist and have
meaning? Is it the semantic web?
Thoughts?
-Cory