The Process of Classification: From Grouping to Knowledge Structuring

Every time you sort laundry into whites and colours, arrange contacts in your phone, or decide which shelf a new book belongs on, you are running a mental program that humans have been refining for thousands of years. That program is classification. In library and information science, classification is not just about putting numbers on book spines. It is a fundamental way of thinking that turns a chaotic pile of entities into an ordered, searchable structure. This post breaks down how the process actually works, from the simple act of grouping to the deeper goal of structuring knowledge itself.

What classification really means 🔗

At its core, classification is the process of making classes of entities. A class is simply a group of things, abstract or concrete, that share at least one common feature. Consider a university batch: the students may be male or female, follow different religions, speak Tamil, Bengali, or Hindi, and hold opposing political views. Yet they form one class because they share a single feature, they are all candidates for the same degree. As the open educational material from INFLIBNET’s classification course explains, a class can be as large as homo sapiens or as small as a single member.

But grouping is only half the story. There can be no grouping without division, just as there is no shadow without light. When you place an apple in the “fruit” basket, you are simultaneously separating it from the vegetables. Grouping and division are two sides of the same coin, and together they form the most basic level of the classification process.

From grouping to ranking to coding 🔗

Real classification goes beyond endless grouping. After the final group is formed, a second activity begins: ranking, or arranging members in a sequence. Think of the UPSC civil services examination. All candidates form one class. The result first divides them into two groups, successful and unsuccessful. The successful candidates are then ranked by marks, and that ranking decides whether someone enters the Administrative, Police, Foreign, or Revenue service. Finally comes a third stage, coding, where each ranked entity is assigned a symbol or number to fix and preserve its order. The grouping of chemical elements into Groups 0 to 8 and their arrangement by atomic number shows all three stages working together. Grouping, ranking, and coding are the building blocks of the entire process.

Understanding co-relation 🔗

If you look beneath grouping and division, you find something more profound. Classification is essentially co-relation, the discovery of relationships between entities. Every member of a group is tied to the others by some commonality, so the moment you admit an entity into a group, you create or reveal a relationship.

Physics is a clear example. It is not merely a member of the broad class called science. It also bears a relationship to Mathematics on one side and Astronomy on the other. These three subjects are intrinsically linked, and classification is what makes that link visible. A family works the same way, with every member related by blood and lineage. This is why co-relation is so powerful for memory and reasoning. The human mind does not store isolated facts well. It remembers things by connecting them to what it already knows. When you classify a new idea, you are attaching it to an existing web of knowledge, which makes it far easier to recall and reason about later.

Why nothing can be understood without it 🔗

Co-relation explains a striking claim in the field: to define something is to classify it. A gun is identified as a firearm, a chair as a piece of furniture, a car as a vehicle. In each case, understanding the entity means placing it within a larger class. This is why classification is described as an aid to memory and reasoning. You cannot truly identify or comprehend an object until you have answered the question, “what kind of thing is this?” That question is a classification question, and answering it is the first step toward knowledge.

The role of characteristics 🔗

The engine that drives the whole process is the characteristic. A characteristic is an attribute, quality, or property of an entity that either relates it to a group or separates it from one. It is the basis on which every division is made.

The examples are everywhere. Divide a group of people by “gender” and you get males and females. Divide university students by “level of education” and you get undergraduate, postgraduate, and research students. Arrange books by their “subject content” and you build a library collection. In each case, a single characteristic decides the grouping. The principle can be written as a simple formula:

Genus + Difference = Species. Take the genus “tables” and add the characteristic of “material,” and you produce wooden tables, glass tables, plastic tables, and metal tables. Apply a series of characteristics one after another, moving from broad to narrow, and you reach finer and finer classes.

What makes a characteristic good 🔗

Not every attribute makes a useful characteristic, and S.R. Ranganathan addressed this directly through his canons of characteristics, a set of four tests for the intellectual stage of classification work. According to the canons described in INFLIBNET’s idea-plane chapter, a sound characteristic should satisfy four conditions. The Canon of Differentiation says the characteristic must split a group into at least two sub-groups, so dividing bicycles by “number of wheels” fails because they nearly all have two. The Canon of Relevance says the attribute must suit the purpose; selecting students for basketball by skin colour is irrelevant, while their height is highly relevant. The Canon of Ascertainability requires the attribute to be tangible and verifiable, which is why you cannot divide living people by their date of death. Finally, the Canon of Permanence insists the characteristic stay stable as long as the purpose holds, ruling out a fluctuating attribute. The summary of Ranganathan’s Prolegomena captures the same logic in compact rules.

Philosophical insights from Mill and Ranganathan 🔗

The idea that classification is a tool of the mind, not just a librarian’s chore, has deep philosophical roots. The English philosopher John Stuart Mill (1806-1873) argued that classification facilitates the operation of the mind in clearly conceiving and retaining the nature of an entity. In his System of Logic, Mill treated classification as inseparable from naming, definition, and reasoning, all of them contrivances that help a person reach truth at the moment it is needed. For Mill, learning to classify well is, in effect, training the mind itself. His broader work on inductive methods shows how tightly he linked classification to the discovery of patterns in nature.

Ranganathan, the architect of modern Indian library science, pushed the idea further. He famously stated that sharpness in thinking, clarity in expression, and exactness in communication all depend ultimately on classification. While Mill approached classification as a logician studying how the mind reasons, Ranganathan approached it as a designer building a working system, the Colon Classification, to map the entire universe of knowledge. A journal study on his contribution notes that his system was built on dividing knowledge into multidimensional, faceted aspects rather than rigid fixed categories. Together, the two thinkers frame classification as both a mental discipline and an engineering practice.

The view that all knowledge is classification 🔗

Mill and Ranganathan are not alone. The educator John Dewey held that all knowledge is classification, and the logician W.S. Jevons argued that all reasoning dealing with general notions consists of classification. A new idea becomes knowledge only when it is related to existing knowledge, which is exactly why researchers cite earlier work. Information turns into knowledge once it is given context and structure, and structure is what classification provides.

Classification in everyday life 🔗

The process is not confined to libraries or philosophy texts. It runs through ordinary routines, often without us noticing. A postman sorts letters several times between posting and delivery so that mail reaches the right address quickly. A fruit seller separates oranges from apples, then sorts the apples into Kashmiri, Shimla, and Golden varieties, and may further grade each variety by quality and price. At every step the seller adds value, which is why classification is sometimes called value addition.

It also shapes decisions that feel deeply personal. Choosing a marriage partner involves a chain of hidden classification acts, weighing characteristics such as age, education, profession, financial status, and values, and applying them in an order that reflects what matters most to you. The analysis of Mill’s logic reminds us that even defining a thing precisely is a classificatory act, since a definition fixes the boundary of a class.

Classifying objects, knowledge, and entities 🔗

The same process scales from a shoe store to the universe of knowledge. Thinkers across history have classified all of knowledge to understand its structure. The Hindu Vedas divided it into Dharma, Artha, Kama, and Moksha. Aristotle split knowledge into theoretical, practical, and productive branches. The general theory of library classification shows how these efforts feed directly into modern schemes that organise documents. Yet classification has limits. It is approximate, never exact, and an entity is rarely one-dimensional. A single person can be a father, an uncle, an engineer, and a Punjabi all at once, which makes placing him in one class genuinely difficult. Classifications are made by people for a purpose, so they reflect the time, place, and society that produced them.

What do you think? If every classification is made for a purpose rather than discovered in nature, can any single library scheme ever be truly “correct,” or only more or less useful? And in your own daily routine, which act of grouping or ranking do you perform so automatically that you never thought of it as classification at all?

References

1. https://ebooks.inflibnet.ac.in/lisp2/chapter/classification-as-a-logical-process-and-daily-activity/
2. https://ebooks.inflibnet.ac.in/lisp2/chapter/work-in-the-idea-plane-canons-of-characteristics/
3. https://www.miskatonic.org/library/prolegomena.html
4. https://www.marxists.org/reference/archive/mill-john-stuart/1843/logic.htm
5. https://link.springer.com/article/10.3103/S0147688211060037
6. https://www.redalyc.org/journal/3843/384357586006/movil
7. https://www.gutenberg.org/files/30866/30866-h/30866-h.htm
8. https://egyankosh.ac.in/bitstream/123456789/33078/1/Unit-3.pdf