SUO: RE: A proposed SUO content outline
Matthew,
Thanks for the clay/vase example - this is very helpful. See my
comment below.
-Ian
> MW: You miss the point. Both a 4D ontology and a 3D ontology
> aim to give a
> complete conceptualisation of the world (I could argue that a
> 4D ontology is
> more capable, but that is unimportant for this discussion).
> In each ontology
> a description can be built up of the world that involves
> different objects.
> Overall each (say) is able to describe the same world. So it
> is not a matter
> of the scope being different, it is a matter of how you
> describe the world
> being different.
>
> MW: Let me try to explain by how a famous example is
> described by the two
> approaches.
>
> MW: There are two lumps of clay that are fashioned into two
> parts of a vase.
> The two parts of the vase/piece of clay are put together to make one
> vase/piece of clay (this is the object(s) of interest). The
> vase is fired
> and then smashed into small pieces.
>
> Continuant/Occurrant Description
>
> There is a Continuant Vase Object, a Continuant Piece of Clay
> Object, an
> Occurrent Vase Life History object, and an Occurrent Piece of
> Clay Life
> History Object (i.e. 4 different objects and 4
> classifications). There are
> relations between the life history objects and the continuant
> objects to
> indicate that one is the life history of the other. There
> could also be a
> relation that showed that the piece of clay and the vase were
> coincident for
> both the life history and the continuant.
>
> The rules of the ontology are that continuants and occurrants
> are disjoint,
> so you need one of each. The rules are also such that at each
> organisational
> level (vase, piece of clay) there are separate objects, even
> if they are
> coincident.
>
> 4D description
>
> There is a single 4D object that is the spatio-temporal extent of the
> vase/piece of clay. It is a member of the class 4D vase, and
> it is a member
> of the class 4D piece of clay.
>
> The rules of the ontology are that if two objects are
> coincident, then they
> are the same object, because spatio-temporal extent is the basis for
> identity of individuals.
>
> MW: What you will see from this is that your ontology
> (although in this case
> both convey the same information) actually determines what
> objects exist,
> and also therefore what classes you are interested in. All
> four objects in
> the continuant/occurrent ontology get merged into one object in a 4D
> ontology (there are cases where there can be more 4D objects than 3D
> objects).
>
> MW: Now I can write down the rules for converting from one
> ontology to the
> other, but if I try to combine the two I just get nonsense,
> because there is
> a basic conflict between the ontologies about what objects exist.
I guess part of what you are arguing here is that the 4D orientation brings
about an overall decrease of theoretical complexity as compared with the
conventional 3D way of looking at things. I guess too that I just don't
agree. Although, as you say, the 4D scheme says that there is just one
object, viz. the space-time worm, while the 3D scheme says that there are
four things and a host of relations among these things, it seems to me that
complexity soon creeps into the 4D orientation. For, on this scheme, we are
required to have rules for individuating the vase/clay space-time worm from
the whole space-time worm that surrounds it and rules for slicing space-time
worms into what are conventionally regarded as stuffs and objects. Without
these individuating and slicing rules, we won't be able to talk about these
stuffs and objects, and then, well, we won't have much to talk about.
Furthermore, as I've mentioned before, I think as much as possible we should
steer clear of questions about what *really* exists. As I've repeated (ad
nauseum at this point), we're not doing philosophy here; we're constructing
an engineering artifact. As long as the ontology permits us to say what we
want to say in a formally specified manner and as long as it permits us to
substantially ease information-sharing among different automated systems, we
will have done our job.