There are many special or “cross-filed” chains of abstractions (of
interconnected concepts) in man’s mind. Cognitive abstractions are the
fundamental chain, on which all the others depend. Such chains are mental
integrations, serving a special purpose and formed accordingly by a special
criterion.
Cognitive abstractions are formed by the criterion of: what is essential?
(epistemologically essential to distinguish one class of existents from all
others). Normative abstractions are formed by the criterion of: what is
good? Esthetic abstractions are formed by the criterion of: what is
important?