# 1999/5/4

#=========#
# Concept #
#=========#

Rand, IOE, page 13

        A concept is a mental integration of two or more units
        possessing the same distinguishing characteristic(s),
        with their particular measurements omitted.

Rand, IOE, page 40, 41

        A definition is a statement which identifies the nature
        of the units subsumed under the concept.

        The purpose of a definition is to distinguish a concept
	from all other concepts and thus keep its units
	differentiated from all other existents.

	The distinguishing characteristic(s) of the units
	becomes the differentia of the concept's definition;
	the existents possessing a "Conceptual Common Denominator"
	become the genus.
	Thus a definition complies with the two essential
	functions of consciousness: differentiation and
	integration.  The differentia isolates the units of a
	concept from all other existents; the genus indicates
	their connection to a wider group of existents.


Knowledge Representation language:

        concept is either unit1 or unit2 or ...
        concept is genus with differentia	# definition

	concept isa* existent
        concept isa genus
        concept is alias
	concept ise unit
        concept isin relationship=infon
        concept has attribute=value
        concept haspart part=partcount

        entity do action=event


        # NOTE:
	# The "primitive units" at the bottom level of an
        # entity-relation hierarchy are the percepts and perceptual
	# judgments which are produced directly from sense data.
	# If a concept is placed at the bottom of the hierarchy,
	# that concept is a "floating abstraction" which has no
	# direct tie to reality.
	# Knowledge Explorer cannot distinguish a "primitive unit"
	# from a "floating abstraction".  That distinction can only
	# be made by the user of Knowledge Explorer.

	# The KE command "!psize cname" counts the number of
	# primitive units in the cname subhierarchy; the command
	# "!hsize cname" counts the number of concepts plus the
	# number of primitive units.
