Entity Modelling

www.entitymodelling.org - entity modelling introduced from first principles - relational database design theory and practice - dependent type theory

Further examples

Ryle's second example is of a child witnessing the march-past of a division of soldiers. After having had battalions, batteries, squadrons, etc. pointed out, the child asks when is the division going to appear. 'The march-past was not a parade of battalions, batteries, squadrons and a division; it was a parade of the battalions, batteries and squadrons of a division.' .

The child might have asked further in discussion of a battalion and its sergeant major, to what battalion does the sergeant major belong? This would have been to fail to understand the scope of the sergeant major or leader relationship (see figure 15). Contrast this to asking in a discussion of a university examination of what institution an external examiner belongs.

It is part of our understanding of the sergeant major relationship that a sergeant major is a soldier within the company, battalion or squadron of which he is the leader.

Figure 15
Based on Ryle's second example of category mistakes.