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?