RE: [EXT] Re: Upper ontologies

Ontology recapitulates philosophy.

From: Marcel Fröhlich <marcel.frohlich@gmail.com>
Sent: Wednesday, 20 January, 2021 19:07
To: phayes@ihmc.us
Cc: Mikael Pesonen <mikael.pesonen@lingsoft.fi>; jflynn12@verizon.net; Gabriel Lopes <gabriellopes9102@gmail.com>; semantic-web <semantic-web@w3.org>
Subject: Re: [EXT] Re: Upper ontologies

Exactly this. Thank you!

Describing the world necessarily means choosing a perspective and there is no reason to believe that an all encompassing "fundamental" perspective exists.

Marcel


Am Mi., 20. Jan. 2021 um 07:24 Uhr schrieb <phayes@ihmc.us<mailto:phayes@ihmc.us>>:
OK, I had promised myself to stay out of these discussions, but …

No, this will not work. It has been tried, many times. Every existing upper ontology was built by people who honestly believed that they would do this, and were willing in some cases to sacrifice years of their professional lives to achieve this. I was part of several of these initiatives, some of them financed by agencies like the US Army and DARPA. But still we have a host of upper ontologies.

And there is a good reason why this happens. Yes, we are all talking about the same one world. And let us assume, for the purposes of argument, that we are all using the same formalism. (Of course not true, but translating between formalisms is relatively straighforward.) Still, we will not all create the same ontology, or even compatible ontologies. (I called this the "diamond of confusion" in a talk about 20 years ago.) And this is because an ontology is, in Tom Gruber's phrase, a formalization of a /conceptualization/, not a formalization of /reality/. And while there is widespread agreement on the nature of the actual world, there is most emphatically not universal agreement on conceptualizations of it. People are still arguing about ontological conceptualizations that were discussed by the Greek philosphers 2000 years ago.

I can illustrate this with a very old, /very/ thoroughly discussed example, which is how to describe things that are extended in time. That is, things in the physical world, not abstract things like numbers or ideas. There are two main ways to think about this.

In one, often called the 4d perspective, all things in time and space occupy some chunk of time and of space, and we describe them by talking about their parts, including their temporal 'slices'. So I – PatHayes4 – am a four-dimensional entity, and we can say things like [**]
Weight(PatHayes4@2020) > Weight(PatHayes4@1966)
to express the regrettable fact that I am getting heavier. The @ symbol here is a function that takes a time-extended thing (me, in this case) and a time, and returns a time-slice of that temporally exended thing. So PatHayes4@1966 is a thing that I might call 'Me in 1966', and PatHayes4 is me throughout my lifetime. The me who is present at any particular time, such as now, is only one momentary timeslice of the entire PatHayes4.

In another way of thinking, there is a fundamental distinction between 'things' (like you and me) and 'events' which happen. (Other terminologies are often used: continuants vs occurrents or perdurant vs endurant. I will stick to things and events.) Things are 3-d, dont have temporal 'parts', and are identically the same thing as time passes. (They continue as time passes; they endure.) Events happen, are temporally extended and have temporal parts. In a nutshell, things are 3-d, events are 4-d. So a football match, a wedding ceremony, a theatre performance are all events, but the players, guests and actors (and many other things) are things. And a guest at the wedding just as he arrives is identically the very same thing as when he is going home after the wedding, though his properties may have changed. Time parameters are typically arguments of properties rather than attached to names, so that my getting fatter might be written
Weight(PatHayes3, 2020) > Weight(PatHayes3, 1966).  Note that the first arguments of these two are identical.

I will not go into the pros and cons of these perspectives. Each of them has been a foundational perspective for an upper ontology in widespread use, and each has been successful. Users and proponents of each have published detailed philosophical defenses of them and critiques, sometimes bordering on slander, of the other. Each of them "works". But they are profoundly incompatible.

The problem is that the 'things' of the second perspective are /logically impossible/ in the first perspective, since they have no temporal parts or extents – they are purely 3-d. So the thing PatHayes3 cannot be identified with PatHayes4. But it also cannot be identified with any particular 'slice' of PatHayes4, since these have different properties, but PatHayes3 is identically the same thing at different times. There simply isn't room in the 4d ontology for things like PatHayes3 which have no temporal extent yet exist at different times. So, one might respond, the worse for 3-d things: but in the second perspective, those 3-d things are the basic fabric of reality, so wthout them there cannot be any events to happen to them.

This incompatibility is not just a philosophical issue: it has ramifications all through the ontologies, affecting how entities must be classified, the syntactic form of the sentences that describe them, even how many of them there are. People learning how to use these ontological frameworks have to learn to /think/ in distinctly different ways.

As my friends know, I could expand on this topic at much greater length, but maybe this will serve to give an idea why the naive idea of just 'choosing the best pieces' of a variety of upper (or lower, for that matter) ontologies is not going to work, any more than trying to make a hybrid car by just taking the best parts of Ford Tbird and an electric golf cart.

There is a reason this field is called 'ontological engineering'.

Pat Hayes

[**] This fragment of formalization is absurdly simplified, but it captures the heart of the matter.


On Jan 18, 2021, at 8:49 AM, Mikael Pesonen <mikael.pesonen@lingsoft.fi<mailto:mikael.pesonen@lingsoft.fi>> wrote:


This is the way I see it too, if there would be effort for the common UO. Take the best parts of the existing UOs and harmonize them.

One would think it would also save some work in future for anyone making domain ontologies. Just choose the best point of view from “Standard Upper Ontology” and start building on it (if there were more than one point of view available in "SUO").

On 17/01/2021 3.46, John wrote:
I think the issue of upper ontologies could be relatively straightforward. Some esteemed organization (W3C?) should initiate an upper ontology working group that would become a major effort. By major effort I don’t mean going to the moon or Mars, but something very major indeed. It would probably require funding from multiple governments to reach the necessary scale of effort. It would select an eminent group of experts as the core working group members who would have the final say in defining the “standard upper ontology”. Inputs would be requested from a very wide source of developers to be considered by the working group. Th e goal of the working group would be to identify, as best as possible, what is true and meaningful in terms of relationships and what is not. A good starting point would be measurements and geographic classes and properties. There is a lot of good work already in these areas that could be leveraged. The next job would be to identify a constrained list of the top-level real world things that most domain specific ontology would need to reference. The ultimate release of the “Standard Upper Ontology” would serve the widest categories of ontology developers and they would all be strongly encouraged to use the standard in order to achieve the maximum interoperability. Those ontology developers who simply cannot live with the standard could go there own way, but realizing they have given up the opportunity to seamlessly interoperate with the majority of the Semantic Web community.

John Flynn
Semanticsimulations.com<http://Semanticsimulations.com>