From BITPlan Wiki
Jump to navigation Jump to search

Comments by Andries van Renssen 2018-01-16:

I am very precise in definitions of concepts and the relations to each other. As a consequence I have a lot of remarks on the article. Whether this is due to differences in understanding of what is denoted by a term or due to precision could be discussed.

  1. Apparently you define ‘Thing’ as something that has an individuality (real or imaginary). I therefore suggest to use the term ‘individual thing’ instead. A clarifying note that it also includes individual occurrences (activities and processes) and individual relations would be helpful.
  2. Concept is indeed often used as a synonym of kind. However, some people consider concept to include (real and imaginary) individual things as well. I think it is valuable to make explicit whether (individual) things are excluded from what a concept is.
  3. I think it is important to make a distinction between concept and collection (or group), although in IT the idea is rather widely adopted that a class (an IT-class) is defined as a collection and when such a class is not distinguished from concept or kind, the consequence is that concept is not distinguished from collection anymore. Which I think is weird, especially in consequences for cases where the number of elements in a collection vary over time or the kinds of the elements in the collection vary over time.
  4. Defining a concept by a complete list is i.m.o. not a good approach. I think it is better to define concept by a description of its criteria for membership. Your example of ‘continent’ illustrates that different people use different definitions for (multiple!) concepts that they all call ‘continent’. However, they talk about different concepts and because they do that with the same term, they are not aware that they use the term for homonyms. Continent-1 and continent-2 have different criteria for membership. And the lists are a consequence of that, not a cause. Furthermore, the lists may still be incomplete. For example due to continent drift over the ages. The discussion about planet or non-planet Pluto is also a nice illustration of this issue.
  5. You state: “At the meta level we consider things that are concepts“. Here you use the term ‘thing’ for kinds, whereas you first distinguished between ‘thing’ and ‘concept/kind’. This would be prevented if you used ‘individual thing’ for ‘thing’ as I described above. Then this sentence would be O.K.
  6. Note that the hierarchy of kinds (the taxonomy) ends in the most generic supertype concept that could be called ‘individual thing’(!). That concept classifies every individual thing as being an ‘individual thing’. In the past I thought that the top of the hierarchy of kinds would be ‘kind’. But I discovered that the concept ‘kind’ classifies kinds. Thus the concept ‘kind’ is a meta concept, in your terminology.
  7. In the statement “Thing is a Concept (on the meta-level)” <is a> means <is classified as a>, being a relation between an individual think and a kind.
  8. But “Concept is a Concept (on the meta-level)” suggests that you distinguish between concept-on-the-concept-level and concept-on-the-meta-level. Are these two differently defined concepts?? And the meaning of <is a> in this case is different, because it relates a kind to a meta concept.
  9. Link can be used as a synonym of ‘binary relation’ not for ‘relation’ in general, because in my opinion a higher order relation should not be called a link.
  10. The example of a meta-concept states that “has connected Ports“ is an example of two ‘links’ between the ship and the ports. What is the meaning of ‘has connected port’? Does a ship ‘have’ a connected port? No. Where is the concept of the movement? The ship ‘is involved in’ the movement. And the ports are also involved in the movement.
  11. I have no fear for Meta. However I question the value of the distinction between concept/kind and meta concept, because in many cases I have seen that what is described is not really on the meta level.
  12. For example, your examples of link concept are not at meta level.
  13. The statement that ‘connects is a name of a link concept’. The meaning of that expression is: the term ‘connects’ denotes a concept that is a kind of relation. In other words, an individual relation (individual thing) is classified by the kind that is called ‘connects’. Why do you call this meta level?