Although
Ranganathan was not the inventor of facet analysis, he is credited as
the first to "systematize and formalize the theory" (Chan
1994, 390). It is said that Ranganthan's idea of a faceted
classification scheme is inspired by a Lego-type toy set. Seeing that
the salesperson can build different toys just by combining the same
pieces in a different way, he builds his classification scheme by
this analogy (Garfield 1984, 40).
The Colon
Classification, just as other classification schemes, starts with a
number of main classes (42), which represent the fields of knowledge.
Each class is
then anaylzed and broken down into its basic elements, grouped
together by common attributes, called facets.
Upon examining
all the facets, Ranganthan notices that there are five main groups
into which the facets fall, and he calls these the fundamental
categories, represented by the mnemonic PMEST in an order of
decreasing concreteness.
Personality
-can be
understood as the primary facet.
-the most
prominent attribute
Matter
-physical material
Energy
-action
Space
-location
Time
-time period
There are also
facets that are common to all the classes. These are called common
isolates. Examples include form and language.
The same facet
can be used more than once.
Notations,
such as numbers and letters, are used to represent the facets, while
punctuation marks are used to indicate the nature and type of the
following facets.
The
classifier's job, therefore, is to combine the available terms that
are appropriate in describing the information package in hand.