The principles governing the systematic organization and representation of subject matter in libraries fall under the broad scope of the Normative Principles of Classification (which determine arrangement) and the specific Principles of Subject Cataloguing (which determine verbal access points).
I. Foundational Normative Principles (Ranganathan's Framework)
The General Theory of Library Classification, largely propounded by S.R. Ranganathan, provides the overarching philosophical and scientific basis for all systematic arrangement of subjects.
A. Fundamental Laws of Library Science
These five laws are the highest normative principles that guide the creation and evaluation of any classification or cataloguing system:
- Books are for Use.
- Every Reader His/Her Book.
- Every Book Its Reader.
- Save the Time of the Reader.
- A Library is a Growing Organism.
B. Principles Guiding Arrangement (Idea Plane)
Classification schemes aim to enumerate the Universe of Subjects, state their interrelations, and fix their order in the idea plane. The intellectual principles guiding subject division include:
- Canons for Characteristics: The quality chosen to divide a subject must be easily differentiated, ascertainable, relevant, and permanent.
- Canon of Exhaustiveness and Exclusiveness: The classes in an array (set of coordinate classes) should be collectively exhaustive and mutually exclusive (to avoid cross-classification, though digital catalogues may permit it).
- Canon of Helpful Sequence: The arrangement of coordinate classes and isolates should be in a sequence that is helpful and consistent to the users. Principles like the Principle of Later-in-Time, Principle of Spatial Contiguity, and Principle of Canonical Sequence are used to achieve this sequence.
- PMEST Postulates: Every compound subject consists of manifestations of the Five Fundamental Categories (PMEST): Personality, Matter, Energy, Space, and Time. These categories are arranged in the order of their decreasing concreteness (PMEST) in the classification number.
- Principles of Facet Sequence: Principles like the Wall-Picture Principle guide the order of facets, stipulating that if Facet B is dependent on Facet A, then A should precede B.
II. Principles of Subject Cataloguing (Verbal Access)
Subject Cataloguing refers to the process of preparing subject entries and organizing them for retrieval, thereby providing access to the intellectual content of the document.
A. Foundational Objectives (Cutter’s Principles)
The principles of subject cataloguing ought to be similar in structure to descriptive cataloguing principles. Charles Ammi Cutter formulated core objectives that are considered foundational principles for subject cataloguing:
- To enable a person to find a book of which the subject is known.
- To show what the library has on a given subject (Collocation).
- To assist the user in the choice of a book as to its character or content.
Haykin stated that the primary purpose is to show which books on a specific subject the library possesses.
B. Core Principles Governing Subject Heading Assignment
- Specific and Direct Entry: A document must be assigned directly under the most specific subject heading that accurately and precisely represents its subject content. If the name of a specific subject is unavailable in the standard list, a broader heading—the most specific authorized heading that covers the content—may be used.
- Consistency and Uniformity: Subject Cataloguing requires the determination and assignment of suitable entries. The subject headings must remain uniform, ordered and specific. Standard lists (like Sears List of Subject Headings, SLSH) aim to keep documents under a uniform subject heading.
- Common Usage and Terminology: The word(s) used to express a subject must represent common usage. The headings can be assigned in accordance with reader’s terminology. This aims to minimize conflict when users approach the catalogue with their own language.
- Collocation and Affiliation: The process should bring together references to materials that treat substantially the same subject, showing affiliations among subject fields. Opponents of the highly structured approach, however, minimize this need, arguing that subject cataloguing is indexing, not classifying.
- Provision of Specific Description: Subject entries must provide a formal description of the subject content in the most precise, or specific terms possible.
C. Structural Principles (Filing and Relationships)
The structure of the alphabetical subject catalogue relies on principles governing relationships and sequence:
- Cross-References: The catalogue uses cross-references to guide a reader from one entry or topic to another. The cross-references direct the user from terms not used as headings (See/USE references) to the authorized headings, and from broader and related topics to the chosen one (See also references).
- Filing Order: In a Dictionary Catalogue, entries are filed in a single alphabetical sequence. In a Classified Catalogue, entries follow the systematic order shown by the Call Number or Class Number notation.
- Logical Integrity: A logical structure of cross references is essential to the effectiveness of the catalogue, ensuring that a user, regardless of the entry point, is led to all of the relevant entries related to their goal.
- Subject Subdivision: Rules govern the use of standard subdivisions to provide further specificity. The perennial problem of deciding whether to subordinate place to topic, or vice versa, has never been fully settled.