Notes on hierarchies
How is hierarchy dealt with in this classification? Is it a feature to be encouraged, or one to be correlated to the discipline under investigation?
Guilford notes that units and systems are easily exchanged in visual - figural areas (1967, p.140). A system can be considered as a unit and vice versa. Does this question the distinction between inclusive and specific concepts? (Another picky point - can you use the centre on the map as the centre of your hierarchy without prejudice?!)
Guilford also gives a multiple grouping test (1967, p.146). This tests the number of different semantic subclasses that can be constructed from a list of objects. These subclasses do not have to be hierarchical. This tests divergent thinking.
Compare this with Eco (1995), and Maynard-Smith & Szathmary (1995). See the hierarchical nature of concepts?
Notes on propositions
I'm not sure about this restriction. We can rename these concepts so that we have nouns as objects and verbs as operators on these objects. Would meta-operations then be links between links??
Another objection could be that some things, such as living organisms, can be considered as both objects and operations. A cow can be considered as an operation - it converts (verb) grass and oxygen into more cow, movement, manure, carbon dioxide, milk, calves, heat, etc. It can also be considered as an object - it can be eaten (verb) by humans, lions, tigers, etc.
I think it's better to call everything a concept and have links where necessary.
Perhaps I should read the article before making any more comments!