DOYLC

I wanted to return to the issue of Pluto, which has already been the subject of a number of posts.  The International Astronomical Union (IAU) created a rich array of issues and problems when it undertook a definitional change that resulted in the demotion of Pluto to the class of "dwarf planets". The topic this time is what exactly did the IAU define? I was watching a PBS special on the status of Pluto a few days ago.  It included scenes from a diner where the genial Neil deGrasse Tyson was asking customers what they thought about the new status of Pluto.  The reponses varied, but the issue at hand was about whether Pluto was "a planet".  The diners all thought that they were dealing with the general concept signfied by the term "planet".  Yet there is reason to think they were mistaken. The IAU resolved (see http://www.iau.org/public_press/news/detail/iau0603/ ) concerning the following: "The IAU therefore resolves that planets and other bodies in o

Stijn commented on my earlier post "What is an Identifying Characteristic?" ( http://definitionsinsemantics.blogspot.com/2011/11/what-is-identifying-characteristic.html ) raising the point that "identification of a thing is dependent on the application".  He lists out things that identify him, and notes that one cannot always be substituted for another.  E.g. a passport cannot always be substituted for a driving license.  It depends on the application, and each application has rules about what can be used as identification.  Stijn asserts that trying to capture all such rules in a definition will create conflict between the parties representing the applications.  So he advises us to separate a definition from capturing such rules. There are a lot of topics compressed into this comment, so I am only going to pick one here.  It is the different classes of identification that should be captured in a definition.  I suggest that these are: Characteristics of the concept

A couple of days ago I was reading some material on a semantics product and came upon the term "role".  We see role used in data modeling where a primary key migrated into a child entity can be assigned a "role name".  This is the name by which the attribute is known in the child entity, and is useful to disambiguate the same attribute migrated for other relationships between the same two entities. You also hear about "role" in the party model.  Rather than say that Unindicted Broker is a client of Overleveraged Bank, and that Unindicted Broker is a prime broker for Overleveraged Bank, we can say that Unindicted Broker is a party that plays two roles with Overleveraged Bank: (a) client; and (b) prime broker. I think that there are deeper issues here.  We think of a relationship in a data model as a line between two entities.  We cannot allocate attributes to the relationship as we can to entities.  Our notations, methodologies, and tools will not allows it

Rob brings up a good point in his comment on The Problem of Abstraction in Definitions of Data ( http://definitionsinsemantics.blogspot.com/2011/12/problem-of-abstraction-in-definitions.html ).  He notes that what I am describing is not really abstraction but really a number of different things. Today it seems the term "abstraction" is used in all kinds of situations when talking about data.  For me, it is often difficult to figure out what "abstraction" is supposed to mean in any one of these situations.  I strongly suspect that at least sometimes it does not really mean anything.  Sometimes I suspect it is even used for marketing hype. The entry for "abstraction" in Baldwin's Dictionary of Philosophy and Psychology describes how abstraction is filtering out of attributes from an instance or a concept to achieve a particular view of the instance or concept.  Rather poetically the entry describes how a child looks at a body of water and becomes fascina