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Topological Ontology and Logic of Qualitative quantity

Qualitative quantity and BFO (Basic Formal Ontology) of /Barry Smith/ and YAMATO (Yet Another More Advanced Top-level Ontology) of /Riichiro Mizoguchi/

Qualitative quantity and BFO (Basic Formal Ontology) of /Barry Smith/ and YAMATO (Yet Another More Advanced Top-level Ontology) of /Riichiro Mizoguchi/

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differentiation enables us to capture a thing, holding a <strong>quantity</strong>(qualia), that can change<br />

keeping its identity as we discuss it below. In other words, any <strong>quantity</strong> exist only one in the<br />

world independently <strong>of</strong> how many things have those quantities as their values. We build an<br />

ontology for each <strong>of</strong> attribute (generic quality) <strong>and</strong> attribute value(<strong>quantity</strong>)<br />

intended to describe things in terms <strong>of</strong> the combination <strong>of</strong> those dependent entities. We<br />

discuss each <strong>of</strong> the two in turn.”<br />

The figure above (marked as Fig.3 in Mizoguchi’s work) shows an example <strong>of</strong> quality.<br />

According to Mizoguchi, “the issue here is how to wisely model this quality. ..Fig. 3 also<br />

shows types <strong>and</strong> individuals underlying the quality. Among them, “John”, “160” <strong>and</strong> “cm”<br />

have no issue to discuss. Let us briefly investigate characteristics <strong>of</strong> the others. Firstly,<br />

“John’s height” is something associated with John <strong>and</strong> exists at the instance level. “Height”<br />

is generic in the sense that the entity which it is associated with is unspecified, but is more<br />

specific than “length” in the sense that it is dependent on what to measure <strong>and</strong> how. This<br />

suggests the notion <strong>of</strong> “quality role” played by length, which is an interesting topic, but it<br />

will be discussed later. The “length” is quite generic because it can be height, depth,<br />

distance, etc. according to the context <strong>and</strong> exists at the class level. Finally, “160cm long”<br />

seems to be <strong>quantity</strong> <strong>and</strong> exists at the instance level.<br />

In summary, issues include (1) if “160cm long” is a quality or a <strong>quantity</strong>, (2) if an instance<br />

<strong>of</strong> a quality is a <strong>quantity</strong> or not, (3) what is “John’s height”, (4) what is “height”, <strong>and</strong> (5)<br />

how is “length” different from “height” The following subsections are devoted to answer<br />

these questions.”<br />

Mizoguchi discusses the example <strong>of</strong> quality on change, illustrating with the “a boy named<br />

John who grows”, where the John’s height was 160cm in 2008 <strong>and</strong> 170cm in 2009. For<br />

Mizoguchi, “ontologically, in order to talk about change properly, we need a non-changing<br />

thing keeping its identity during the change process, otherwise, there cannot exist a change<br />

but just a difference. In the case <strong>of</strong> growing John, John <strong>and</strong> his height must keep their<br />

identities. That is, “John’s height” must have the same identity at the times <strong>of</strong> 2008 <strong>and</strong><br />

2009. The values, on the other h<strong>and</strong>, are 160cm in 2008 <strong>and</strong> 170cm in 2009, respectively,<br />

<strong>and</strong> they have their own different identity. This analysis reveals that “John’s height” has<br />

something having its identity <strong>and</strong> it is generic in the sense that its possible values are<br />

indefinite.”<br />

Later one Mizoguchi discusseses the “Quality role”:<br />

“We here discuss the notion <strong>of</strong> quality role. Many <strong>of</strong> the qualities people know are not basic<br />

quality (This term is temporary <strong>and</strong> will be renamed as generic quality type later.-<br />

Mizoguchi) but quality role. Let us take an example <strong>of</strong> height. It is a quality role whose<br />

basic quality is length. In the role theory (Mizoguchi 07), it can be said that “height role is<br />

played by length in the context <strong>of</strong> a human body”. Height is what is measured in the<br />

direction roughly along the vertical axis from the ground level to the top. Similarly, depth,<br />

width <strong>and</strong> distance are quality roles played by length as well. It is just like a man plays a<br />

husb<strong>and</strong> role when he has got married <strong>and</strong> like a human plays a teacher role in the context<br />

<strong>of</strong> a school. Let us call quality such as length as basic quality temporarily. Examples <strong>of</strong> basic<br />

qualities include length, area, mass, temperature, flow rate, voltage, etc. Basic qualities are<br />

context-independent <strong>and</strong> intrinsically represent kinds <strong>of</strong> quality, <strong>and</strong> roughly equal to<br />

physical dimensions. Quality roles include height, depth, input flow rate, maximum weight,<br />

area <strong>of</strong> cross section, etc.“<br />

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