Classifications

Definition (Reference books)
Definition (Ronald Abler, John S. Adams, Peter Gould)

Function (James G. March, Herbert A. Simon)
Function (M. L. J. Abercrombie)
Function (Deobold B. Van Dalen)
Function (Abraham Kaplan)
Function (Ronald Abler, John S. Adams, Peter Gould)
Function (Nicholas Rescher)
Function (Irving M. Copi)

Features (M.L.J. Abercrombie)
Features (R. Harré)
Features (J. Brian McLoughlin)
Features (Paul Davidson Reynolds)

Requirements (Irving M. Copi)
Requirements (W. Ward Fearnside and Willim B. Holther)
Requirements (J. Brian McLoughlin)
Requirements (Paul Davidson Reynolds)
Requirements (Louise E. Rorabacher, Georgia Dunbar and Clement Dunbar)

Related concepts
Category - Categorizing (Jerome S. Bruner, Jacqueline J. Goodnow and George A. Austin)
Category - Categorizing (Neil McK.Agnew, Sandra W. Pyke)
Category - Categorizing (Union of International Associations)
Class (Vincent E. Barry)
Class (Irving M. Copi)
Code - Coding (John Madge)
Code - Coding (Union of International Associations)
Continuum (Henri Poincaré)
Elements (L. Susan Stebbing)
Generalizations (Henri Poincaré)
Generalizations (R. Harré)
Index - Indexing (Dictionary of New Information Technology)
Order - Ordering (J. Bronowski)
Order - Ordering (R. Harré)
Similarity (Peter Caws)
Typology (Union of International Associations)
Typology (Paul Davidson Reynolds)

Classical quotations (Plato)
Classical quotations (Henri Poincaré)

Definition

[1974] The American Heritage Dictionary of the English Language
“1. To arrange according to class or category.”

[1981] Longman Lexicon of Contemporary English
“1. To arrange or place (animals, plants, books, etc.) into classes; divide according to class.” (N 194)

[1983] Dictionary of the History of Science
“The arrangement of objects or entities into groups or classes, usually on the basis of perceived similarity and difference.”

[1971] Ronald Abler, John S. Adams, Peter Gould, Spatial Organization, Prentice Hall, Englewood Cliffs, N. J.
"Classification is the systematic grouping of objects or events into classes on the basis of properties or relationships they have in common." (Chapter 6, p. 151)

Function

[1953] Irving M. Copi, Introduction to Logic, Macmillan, New York, Sixth edition 1982
“There are several motives that may lead us to classify things: one is practical, another theoretical.”
Practical. “The larger the number of objects, the greater the need for classifying them. A practical purpose of classification is to make large collections accessible.” (e.g. libraries, museums, etc.).
Theoretical. “In considering the theoretical purpose of classification, we must realize that the adoption of this or that alternative classification scheme is not anything which can be true or false. Objects can be described in different ways, from different points of view. The scheme of classification adopted depends upon the purpose or interest of the classifier. Books, for example, will be classified differently by a librarian (e.g. by subject), a bookbinder (e.g. by their binding’s needs), a bibliophile (e.g. its rarity).”
“One classification scheme is better than another, from the scientist’s point of view, to the extent that it is more fruitful in suggesting scientific laws and more helpful in the formulation of explanatory hypotheses.” (Chapter 13, pp. 496-497)

[1958] James G. March, Herbert A. Simon, Organizations, Wiley & Sons, New York, 1966
“One particular form or summarization is classification. When a particular thing has been classified as belonging to a species, all the attributes of the species can be ascribed to the individual instance of it.” (p. 155)

[1960] M. L. J. Abercrombie, The Anatomy of Judgement, Penguin, Harmondsworth, 1979
“[Classification] can give us more information than we have at the moment direct access to - that is it helps us to extrapolate and to predict. A famous example of this can be cited from chemistry. The system of classification of the elements according to atomic weight and chemical properties devised by Mendeléef was such that he was able to predict the discoveries of certain elements not at that time known.” (Chapter 8, p. 137)

[1962] Deobold B. Van Dalen, Understanding Educational Research. An Introduction, McGraw-Hill Book Company, New York, 1979
“Classification schemes help workers in a discipline to
(1) identify and deal with individual cases;
(2) communicate with colleagues more efficiently and accurately about phenomena in their fields;
(3) search for additional resemblances that members of categories may have in common;
(4) formulate hypotheses that suggest why differences between categories exist.” (Chapter 2, p. 19)
“By classifying phenomena in accordance with their resemblances, scientists organize masses of information into a coherent and unified structure that is useful.” (Chapter 2, p. 19)
Drawback: by summarizing information about the entities in categories, scientists gain a better understanding of phenomena, but they also lose some information - some of the richness and variety of individual differences. Any classification scheme magnifies some differences and ignores others.” (Chapter 2, p. 19)

[1964] Abraham Kaplan, The Conduct of Inquiry. Methodology for Behavioral Science, Chandler Publishing Company, Scranton, Pennsylvania
“The purpose of scientific classification is to facilitate the fulfillment of any purpose whatever, to disclose the relationships that must be taken into account no matter what.” (Chapter II, p. 51)

[1971] Ronald Abler, John S. Adams, Peter Gould, Spatial Organization, Prentice Hall, Englewood Cliffs, N. J.
"The purpose of classification is to give order to the things we experience. We classify things so that we may learn more about them."
"If we did not classify objects and experiences in commonly accepted terms we could not transmit information because no one would understand what we were talking about." (Chapter 6, p. 149)

[1979] Nicholas Rescher, Cognitive Systematization, Basil Blackwell, Oxford
“Since the days of Plato’s stress on dihairesis (i.e. taxonomic division) there has been general agreement that the principal instrument by which we introduce systematic order into our knowledge is classification.”
“Classification is, of course, a tool of cognitive systematization in general.” (Chapter XII, p. 182)

Features

[1960] M. L. J. Abercrombie, The Anatomy of Judgement, Penguin, Harmondsworth, 1979
“… when we classify a thing, we are deciding which of our schemata are appropriate to it.” (p. 141)
“Judgement of the suitability of a system of classification is presumably based on the perception, not necessarily conscious, of a pattern of correlated features, and seems to involve the same kind of processes as aesthetic judgement.” (p. 143)

[1963] R. Harré, An Introduction to the Logic of the Sciences, Macmillan & Co., London
“The obvious way to classify things is to arrange them in kinds. We put those things together which have certain features in common.” (p. 36)
“Since what properties we select to make our classifications are to some extent arbitrary there are a great many ways in which we can classify things. The classification we come to accept will be that which brings out differences and combinations of properties that are important to us.” (p. 37)

[1969] J. Brian McLoughlin, Urban and Regional Planning. A Systems Approach, Faber, London, 1973
“Classification should be flexible in that it can be used either in great detail or in summary form, and be capable of many different kinds of re-combination without altering the classification itself.”
“The classification scheme should make the data suitable for machine processing.”
“It should be possible to expand and modify the classification without altering its basic features and without rendering past records useless.” (p. 130)

Requirements

[1953] Irving M. Copi, Introduction to Logic, Macmillan, New York, Sixth edition 1982
“A characteristic is important when it serves as a clue to the presence of other characteristics.”
“An important characteristic, from the point of view of science, is one that is causally connected with many other characteristics, and hence relevant to the framing of a maximum number of causal laws and the formulation of very general explanatory hypotheses. That classification scheme is best ... which is based on the most important characteristics of the objects to be classified”
“If later investigations revealed other characteristics to be more important, that is, involved in a greater number of causal laws and explanatory hypotheses, it would be reasonable to expect the earlier classification scheme to be rejected in favor of a newer one based upon the more important characteristics.” (p. 497)

[1959] W. Ward Fearnside and William B. Holther, Fallacy, Prentice-Hall, Englewood Cliffs, New Jersey
"1. The classification must be exhaustive (nothing left out)
2. The classification must be exclusive (there must be what is called a fundamentum divisionis)
3. The classification must be adequate to the purpose for which it is designed
4. The division of the classification must be precise enough to avoid serious marginal cases." (p. 36)

[1969] J. Brian McLoughlin, Urban and Regional Planning. A Systems Approach, Faber, London 1973
“Classification should be flexible in that it can be used either in great detail or in summary form, and be capable of many different kinds of re-combination without altering the classification itself.”
“The classification scheme should make the data suitable for machine processing.”
“It should be possible to expand and modify the classification without altering its basic features and without rendering past records useless.” (p. 130)

[1971] Paul Davidson Reynolds, A Primer in Theory Construction, Macmillan, New York 1986
1) exhaustiveness: of all the ‘things’ being classified, there is no item that cannot be placed in the scheme;
2) mutual exclusiveness: there is no ambiguity about where each ‘thing’ is to be placed in the scheme;
3) consistent with the concepts used in the statements that express the other purposes of science. (p. 5)

[1988] Louise E. Rorabacher, Georgia Dunbar and Clement Dunbar, Assignments in Exposition, Harper & Row, New York, Ninth Edition
- Choose and apply a single principle of classification
- Do not let your classes overlap
- Make your classification reasonably complete
- Introduce subclasses as needed.
(from p. 221)

Related Concepts

• Category - Categorizing

[1956] Jerome S. Bruner, Jacqueline J. Goodnow and George A. Austin, A Study of Thinking, Science Editions, New York, 1966
“To categorize is to render discriminably different things equivalent, to group the objects and events and people around us into classes, and to respond to them in terms of their class membership rather than their uniqueness.” (Chapter I, p. 1)
“... virtually all cognitive activity involves and is dependent on the process of categorizing. More critical still, the act of categorizing derives from man’s capacity to infer from sign to significate.” (p. 246)

[1969] Neil Mck. Agnew, Sandra W. Pyke, The Science Game. An Introduction to Research in the Behavioral Science, Prentice-Hall, Englewood Cliffs, New Jersey
“By using a larger number of categories you gain two advantages: (1) you don’t try to squeeze your data into an inappropriate category; and (2) you usually increase your chances of getting independent agreement among different observers”. (p. 110)
"... it is vitally necessary that you provide a sufficient number of realistic and clear categories." (p. 111)

[1986] Union of International Associations eds., Encyclopedia of World Problems and Human Potential
“1. Generally groupings of objects or phenomena according to similar properties and characteristics.
2. The grouping of properties and characteristics into fundamental classes using analytical reduction.
3. The most fundamental classes of concepts of universal properties, such as moving or stationary.
4. In Plato essence or being, motion, rest, sameness or identity and difference. In Aristotle essence quantity, quality, relation, place, time, position, state, action and affection.
5. In religious philosophy the categories exist apart from matter, as divine forms, archetypes or energies.
6. In scientific philosophy new categories have been added such as system and structure.” (KC00779)

• Class

[1980] Vincent E. Barry, Practical Logic, Holt, Rinehart and Winston, New York, Second Edition
“... a class being a group of things having a common property or characteristic.” (Chapter 11, p. 256)

[1982] Irving M. Copi, Introduction to Logic, Macmillan, New York, Sixth Edition
Class: “the collection of all objects that have some specified characteristic in common.” (Chapter 5, p. 178)

• Code - Coding

[1953] John Madge, The Tools of Social Science, Longmans, London, 1965
“Coding - that is to say the fixing of categories into which each type of information is divided - is an essential stage in statistical inquiries.” (p. 228)
Suggestions: (1) adopt an existing authoritative classification wherever to do so will not distort results or prejudice aims; (2) is always better to have too many separate categories (that can be amalgamated) than to start with too few (that cannot be split up without going back to the original material).

[1986] Union of International Associations eds., Encyclopedia of World Problems and Human Potential
“A code is understood here to be a system of symbols for the representation of information and rules governing their combination. The freedom of the code is therefore restricted by special conventions, and usually by the obligation imposed upon him to follow a certain hierarchical order.” (KC0622)

• Comparison

[1954] Eugene E. White, Practical Public Speaking, Macmillan, New York, Third edition 1978
- "The Literal Comparison: compares ideas or objects of the same class such as rivers to rivers, cities to cities, etc." "The basis of analogical reasoning is this: if two things possess essentially comparable characteristics, a proposition that is true of one may be true of the other." (p. 146)
- "The Figurative Comparison: stresses unique relationships between objects or ideas of different classes such as a man to a mountain, a government to a ship, etc." "An idea frequently assumes greater clarity, significance, and acceptability if singular resemblances can be pointed out between that idea and a second idea that appears to be completely different." (p. 150)

[1988] Louise E. Rorabacher, Georgia Dunbar and Clement Dunbar, Assignments in Exposition, Harper & Row, New York, Ninth Edition
“Comparison as a pattern of thought involves holding up two similar but not identical objects, situations, people, ideas, and so on, to determine in detail their likeness and differences (a through comparison must always include contrast to be complete).” (p. 199)
Two patterns are appropriate for organizing information in a comparison:
a. the opposing pattern (I A.B.C.; II A.B.C.) to emphasize differences on the whole;
b. the alternating pattern (IA., IIA; IB., IIB.; IC., IIC.) to emphasize differences on specific aspects. (pp. 200-201)

• Continuum

[1902] Henri Poincaré, La Science et l’Hypothèse, Champs Flammarion, Paris, 1968
“… un système d’éléments formera un continu, si l’on peut passer d’un quelconque d’entre eux à un autre également quelconque, par une série d’éléments consécutifs enchaînés de telle sort que chacun d’eux ne puisse se discerner du précédent. Cette chaîne est à la ligne du mathématicien ce qu’un élément isolé était au point.” (p. 59)
“A mesure qu’on connaît mieux les propriétés de la matière, on y voit régner la continuité.” (p. 190)

• Elements

[1949] L. Susan Stebbing, A Modern Elementary Logic, Methuen & Co., London, Fourth Edition
“Those instances of the class which exist are called the members of the class, or sometimes the elements of the class.” (Chapter 5, p. 77)

• Generalizations

[1902] Henri Poincaré, La Science et l’Hypothèse, Champs Flammarion, Paris, 1968
“[Car] sans généralisation, la prévision est impossible.” (p. 158)
“[Observons] d’abord que toute généralisation suppose dans une certain mesure la croyance à l’unité et à la simplicité de la nature.” (p. 161)
“Toute généralisation est une hypothèse ; l’hypothèse a donc un rôle nécessaire que personne n’a jamais contesté.” (p. 165)

[1963] R. Harré, An Introduction to the Logic of the Sciences, Macmillan & Co., London
I. Member generalizations. “The process of applying a certain predicate to all members of a class having a certain defining property is generalization.” (p. 12)
II. Substance generalization. “Another method of description [generalization] begins with what has been called feature-placing.“ “Substances are those stuffs which form large scale features of the world.“ (p. 14)

• Index - Indexing

[1982] Dictionary of New Information Technology, Kogan Page, London
“Index: at the most general level, an index consists of a series of identifiers each of which characterizes a document, abstract, or other piece of information. These identifiers can be arranged in a variety of ways to suit user needs. Examples are indexes of authors, titles, dates, countries, institutions, report numbers.” (p. 90)
“Indexing: the process by which ‘labels’ are produced for documents, or for information.” (p. 90)

• Order - Ordering

[1951] J. Bronowski, The Common Sense of Science, Penguin, Harmondsworth, 1968
“Order is the selection of one set of appearances rather than another because it gives a better sense of the reality behind the appearances. ... any selection ... implies, and imposes, an interpretation.” (p. 54)

[1963] R. Harré, An Introduction to the Logic of the Sciences, Macmillan & Co., London
“At the back of any ordering is a principle or principles according to which the ordering is made.” (p. 34)

• Similarities

[1965] Peter Caws, The Philosophy of Science, D. Van Nostrand, Princeton, New Jersey
- Genetic similarity: “between objects having similar origins (produced by similar forces, under similar conditions, and so on)”;
- Structural similarity: “between objects having similar constituent parts, or similar relations between their parts”;
- Functional similarity: “between objects having similar behavior”;
- Apparent similarity: similarity of form, shape, pattern. (from p. 41)

• Typology

[1971] Paul Davidson Reynolds, A Primer in Theory Construction, Macmillan, New York, 1986
The application of a typology to phenomena should result in:
1) exhaustiveness: of all the ‘things’ being classified, there is no item that cannot be placed in the scheme;
2) mutual exclusiveness: there is no ambiguity about where each ‘thing’ is to be placed in the scheme;
3) consistency: typologies should be consistent with the concepts used in the statements that express the other purposes of science.
(Introduction, p. 5)

[1986] Union of International Associations eds., Encyclopedia of World Problems and Human Potential, K. G. Saur, München, Second Edition
“A system of groupings, usually called types, which aid demonstration or inquiry by establishing a limited relationship among phenomena. The identity of the members of each type is defined in terms of specified attitudes which are mutually exclusive and collectively exhaustive. Any such type may represent one kind of attribute or several and need include only those features of the phenomena which are significant for the problem in question.” (KC0484)

Classical quotations

[around 350 B.C.] Plato, Philebus
“But the infinity of kinds and the infinity of individuals which there is in each of them, when not classified, creates in every one of us a state of infinite ignorance.” ( Great Books of the Western World, Book 6, p. 612)

[1902] Henri Poincaré, La Science et l’Hypothèse, Champs Flammarion, Paris, 1968
“Le savant doit ordonner ; on fait la science avec des faits comme une maison avec des pierres ; mais une accumulation de faits n’est pas plus une science qu’un tas de pierres n’est une maison.” (p. 158)

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