Library classification might seem like a simple task of organizing books on shelves, but it is actually a complex intellectual process that requires careful planning and systematic principles. In the early 20th century, an Indian librarian and mathematician named S.R. Ranganathan revolutionized how we think about organizing knowledge in libraries. He did this by introducing a groundbreaking methodology called the postulational approach, which transformed classification from an art form into a rigorous scientific discipline. Rather than relying on intuition or tradition, Ranganathan’s method provided librarians with a set of predefined theories, laws, and principles that could guide their classification decisions. This approach became a turning point in library science, influencing how libraries worldwide organize and manage information.
Table of Contents
Understanding the postulational approach
At its core, the postulational approach is a method of creating classification systems based on a pre-meditated theory expressed through laws, canons, principles, and postulates. Instead of designing a classification system through trial and error, librarians using this approach start with a clear theoretical foundation and work logically from there. A postulate, in Ranganathan’s terms, is a fundamental statement that serves as a starting point for all subsequent decisions in the classification process.
What makes the postulational approach distinctive is its scientific rigor. The approach sets up several models, each with its own set of postulates as a basis, allowing librarians to choose the particular model whose postulates are most helpful for their purposes. This flexibility combined with systematic thinking allows classification systems to be both rational and adaptable. Before Ranganathan introduced this methodology, library classification was largely descriptive-librarians applied rules of thumb developed over time, but there was no unified theoretical framework explaining why those rules worked.
The shift to a postulational approach meant that librarians could now understand the principles behind their classification decisions. They could evaluate different systems objectively and even design new ones with confidence, knowing they were following a sound theoretical foundation rather than relying solely on experience or convention.
Ranganathan’s structured theoretical framework
S.R. Ranganathan’s contribution to library science extended far beyond simply proposing the postulational approach. He formulated the Five Laws of Library Science in 1928, which were published in 1931 and immediately became the basic fundamentals of the library management system. These five laws-“Books are for use,” “Every book its reader,” “Every reader his book,” “Save the time of the reader,” and “A library is a growing organism”-provided the philosophical underpinning for all his theoretical work.
Building on these foundational laws, Ranganathan developed a comprehensive framework that included multiple levels of theoretical guidance. His framework consisted of several key components: Laws, which govern the overall aspects of library work; Canons, which serve as principles guiding how library classification should be carried out; Postulates, which form the groundwork for specific classification decisions; and Devices, which are the practical techniques and tools used to implement the classification system.
What was remarkable about Ranganathan’s approach was its comprehensiveness. He identified three planes of work for library classification-the Idea Plane, the Verbal Plane, and the Notational Plane-and formulated a separate set of canons for work in each plane. This meant that every aspect of the classification process, from initial intellectual analysis to final numerical notation, was guided by explicit principles. The rigor of this approach transformed classification from an intuitive craft into a systematic science that could be learned, taught, and continuously improved.
The three planes of work in classification
One of Ranganathan’s most important contributions was dividing the entire work of classification into three distinct planes, each with its own purpose and set of principles. Understanding these three planes is essential to grasping how the postulational approach works in practice.
The idea plane
The Idea Plane is where the intellectual work of classification begins. At the idea plane, all aspects of the universe of knowledge are analyzed by its structure, dimensions, qualities, characteristics, kinds of relationship, and bonds of strength among each item of knowledge. Here, a librarian must think deeply about concepts and how they relate to one another. For example, if a library is acquiring books on plant diseases, the librarian must first conceptually organize this domain-understanding which plants are involved, what types of diseases exist, which are most significant, and how they interconnect.
At this plane, a librarian applies specific canons related to characteristics and differentiation. The work here is purely intellectual and creative, requiring an understanding of the subject matter and how knowledge in that domain is structured. This is the “message” or core idea that will eventually be expressed in words and then represented in numbers.
The verbal plane
Once ideas have been clearly conceptualized, they must be expressed in language. The Verbal Plane is the step in any classification process where work is to express ideas in words or terms-it is the naming of ideas in order to facilitate communication and individualization of thought-content. This is more complex than it might initially appear. The same concept might be called different names in different contexts, or one name might refer to multiple concepts.
Ranganathan’s canons for the verbal plane address these challenges. His canons for the verbal plane include the canon of context, canon of enumeration, canon of currency, and canon of reticence. For instance, the canon of currency emphasizes that terms should be contemporary and in current use, while the canon of context ensures that terms are unambiguous within their particular domain. These rules help librarians choose terminology that is precise, widely understood, and likely to remain relevant over time.
The notational plane
The final plane is where ideas and words are converted into symbols, typically numbers. At the notational plane, words are replaced by symbols pregnant with precise meaning, with ordinal numbers often used as helpful symbols, and a distinctive feature being the uniqueness of the idea represented by an ordinal number and the total absence of homonyms and synonyms. This is where the classification system’s notation-such as the numbers you see on library book spines-is developed.
The notation is crucial because it must be brief yet comprehensive, flexible enough to accommodate new subjects, and capable of being arranged in a logical order. When you see a book labeled with a Colon Classification number like “821.4:92,” you are seeing the result of work across all three planes-the intellectual organization of knowledge, the verbal expression of that knowledge, and finally its symbolic representation in a notational system.
The impact on library science and practice
The postulational approach fundamentally transformed library science into a systematic discipline. When Ranganathan designed his Colon Classification between 1924 and 1933, he later formulated objective and even mechanical methods to design a classification system, making the theory so comprehensive and objective that it became a theory of classification in general. This was a watershed moment in library science because it demonstrated that classification could be approached scientifically rather than haphazardly.
Unlike previous classification systems that were hierarchical and enumerative, the Colon Classification was faceted and analytico-synthetic in nature, allowing for much greater flexibility and specificity in representing complex subjects. Libraries using this system could accommodate new knowledge domains without completely restructuring their existing classifications.
The postulational approach also influenced how librarians evolved from mere custodians of books to active facilitators of knowledge, guiding users in their search for information and connecting them with the right resources. By providing explicit principles and guidelines, Ranganathan’s framework enabled librarians to make more informed decisions about how to organize collections in ways that genuinely served their users.
The long-term impact of this approach cannot be overstated. Modern digital libraries, search algorithms, and knowledge organization systems all trace their intellectual lineage to the principles Ranganathan established. His emphasis on user-centered organization and systematic principles influenced library practices worldwide, and even today, his theories inform how information professionals approach the challenge of organizing knowledge in an increasingly complex information environment.
What do you think? If you were designing a classification system for your college library, which of Ranganathan’s three planes do you think would be most challenging to implement well, and why? How might the principles of the postulational approach help organize information in fields beyond library science, such as in managing digital content or corporate knowledge systems?
References
- https://egyankosh.ac.in/bitstream/123456789/33082/1/Unit-6.pdf
- https://www.studocu.com/in/document/mahatma-gandhi-university/library-science/unit-3-postulational-approach/34934502
- https://www.lisedunetwork.com/five-laws-of-library-science/
- https://ebooks.inflibnet.ac.in/lisp2/chapter/work-in-the-verbal-plane-canons-of-terminology/
- https://ebooks.inflibnet.ac.in/lisp2/chapter/work-in-the-idea-plane-canons-of-characteristics/
- https://www.slideshare.net/slideshow/sr-rangatathanthree-planes-of-work/63296743
- https://www.caluniv.ac.in/academic/LibSc/Study/nm.pdf
- https://associates.ucr.edu/306cexn.htm
Leave a Reply