Topic: classification

topics > philosophy > Group: formalism

data type
database model
natural language
object-oriented programming
philosophy of science

abstraction by common attributes
decomposition of a system into levels
definition by example
fundamental concepts such as type, attributes, relationships are all the same
hierarchical structures
inheritance of properties
meaning of words
metaphysics and epistemology
object-oriented classes
object-oriented design
object-oriented prototypes
objects as a set of attributes
problem of classifying information
set definition by extension or intension


Classification is a fundamental way of organizing the world. For every object, we assign one or more classes. Usually these classes reflect a common set of attributes. In turn, defining a class for an object gives the object a set of properties. Classification is one of the main ideas behind data typing and object-oriented programming.

A taxonomy is a classification system, typically with a hierarchical structure.

Classification can be by example or prototypical objects.

A class is itself an object with a class. It can have properties, but predicates about entities may not generalize to predicates about classes. (cbb 1/90)

Subtopic: category as reality up

Quote: language is a classification of the world into concepts for modeling and manipulation [»engeDC_1963]
Quote: sets are classes; the notion of class is so fundamental to thought that we cannot hope to define it [»quinWV_1969]
Quote: subject/predicate sentences categorize things; a subject denotes an object and a predicate identifies a category; true if the object fits [»martAP_1990]
Quote: understanding notion of classification leads to fundamental issues in math and philosophy [»wegnP10_1986]
Quote: even though Dani has only two basic color categories, the primary color categories are psychologically real for Dani speakers [»lakoG_1987]
Quote: classify by primary being or form, not by accidental characteristics; e.g., divide footed animals into cloven and uncloven, but not feathered or featherless [»aris_322a]
Quote: conceptual schemes organize experience; reality is relative to a scheme; translation may not be possible [»daviD11_1974]

Subtopic: classification as language up

Quote: the subject classification of vocabularies goes back to Sanscrit, Pollux, and Aelfric; for example, Gods, Agricultural Tools, Occupations [»sparK7_1972]
Quote: people distinguish classes via short descriptions; using language specific to those classes; brevity is achieved without lose of information [»bongM_1967]
Quote: a Perceptron classifies all images with one language; e.g., A is stimulated more frequently by the 2nd class [»bongM_1967]
Quote: examples of Bongard patterns; each with a short description; e.g., 3 parts vs. 5 parts [»bongM_1967]
Quote: a hierarchy provides well-matched links with good residue throughout the structure; for example, 'Cat' is part of 'the rest' link from the 'Maple' node [»furnGW3_1997]
Quote: Agenda categories become the words of a language for describing information and its interrelationships [»kaplSJ7_1990]
Quote: Agenda's categories forms a vocabulary for making assertions about items [»kaplSJ7_1990]
Quote: organizing an object means organizing its components; you can not organize a closet independent of organizing its shoes and shirts [»daviD11_1974]

Subtopic: classification of ideas, thesaurus up

Quote: in a thesaurus, words are classified by their signification, by the ideas which they express
Quote: Wilkins published a Universal Character in 1668 through the Royal Society; a massive hierarchical classification of ideas and synonyms [»sparK7_1972]
Quote: the classification of ideas is the true basis on which words (the symbols of ideas) should be classified; a basis for the philosophy of language [»rogePM_1853, OK]
Quote: Roget's top-level categories: abstract relations, space, material world, intellect, volition, and feeling [»rogePM_1853, OK]
Quote: Roget used two parallel columns to show words and their opposites on the same page [»rogePM_1853, OK]

Subtopic: classification for retrieval up

Quote: Dewey paraphrased: organize your books so that you can find them, and never mind the philosophy [»sparK7_1972]
Quote: Roget built his thesaurus for practical utility in locating words. He avoided needless refinement [»rogePM_1853, OK]
Quote: automatic categorization of search results by a small model of queries and a large, domain-specific terminology model; DynaCat for medicine [»pratW7_1999]

Subtopic: basic categories up

Quote: index consistency highest for checktags, a small set of basic-level categories preprinted on the indexing form [»funkM4_1983]
Quote: basic classes occur in the middle of the class hierarchy but object-oriented class design proceeds from top to bottom [»taivA11_1997]
Quote: basic-level categories such as 'chair' or 'water' are human-sized; they depend on how people interact with objects [»lakoG_1987]
Quote: basic level of abstraction carries the most information; most differentiated; real-world [»roscE7_1976]
Quote: basic categories maximize cue validity; superordinate categories share fewer attributes; subordinate categories share more attributes
Quote: for nonbiological taxonomies, basic categories described by typical muscle movements; e.g., sitting down on a chair [»roscE7_1976]
Quote: objects in a basic category have similar shapes
Quote: have mental images of concrete objects in basic categories; superordinate objects not easily identified, subordinate objects like the corresponding basic category [»roscE7_1976]
Quote: for nonbiological taxonomies, basic categories have more attributes than superordinate categories [»roscE7_1976]
Quote: for nonbiological taxonomies, basic categories are identified by shared attributes
Quote: sorting objects into basic level categories is virtually perfect; significantly better than sorting into superordinate categories [»roscE7_1976]
Quote: nearly total agreement in the use of basic level names for objects; superordinate and subordinate names seldom used for free-naming [»roscE7_1976]
Quote: a child's first utterances of concrete nouns are at the basic level of abstraction; basic level names used almost exclusively during free naming [»roscE7_1976]

Subtopic: collections with similar properties up

Quote: classification is for describing uniformities of collections of instances [»wegnP10_1986]
Quote: a category is a number of objects which are considered equivalent; e.g., dog, animal [»roscE7_1976]
Quote: things are classified into types for naming scope, validity constraints, and relationship domains; groups are mutually exclusive [»kentW_1978]
Quote: in ML, words are grouped into categories which can define properties of their members [»spooCR4_1986]
Quote: an entity set is a grouping of entities with similar properties [»senkME1_1973]
Quote: similar objects grouped by classes which prescribe common attributes and constraints [»borgA10_1986]
Quote: object-oriented programming distinguishes general properties of a class from specific properties of an instance
Quote: a class of objects is defined by a pattern giving a set of attributes and a set of actions [»handP_1981]
Quote: categories are defined by patterns; includes data types, classes, procedures, and functions [»handP_1981]

Subtopic: category as family resemblance up

Quote: define categories by family resemblance instead of criterial features
Quote: Kevo uses family resemblance instead of explicitly sharing object representations [»taivA11_1997]

Subtopic: category as prototype up

Quote: the focal colors serve as prototypes or cognitive reference points for a category; other physical categories have prototypes
Quote: prototypical members of a category share the most attributes with other members of the category and the fewest attributes from other categories; experiments with natural and artificial categories [»roscE_1975]

Subtopic: individual vs. class up

Quote: statements about individuals and classes are different logical types; hard to predict one from the other [»bateG_1979]
Quote: a Smalltalk class is also an object; it handles messages
Quote: object classes are themselves objects; can attach definitional information and sometimes attributes [»borgA1_1985]

Subtopic: category and taxonomy up

Quote: a taxonomy is a hierarchy of categories; most abstract is the root [»roscE7_1976]
Quote: species can not be classified into circles or prearranged groups
Quote: no species has come into existence twice

Subtopic: unrelated classes, irrelevant up

Quote: a Perceptron has no notion of irrelevant objects or trash; only uncertainty

Subtopic: IS-A links up

Quote: although IS-A links are widely used for classification, they have different meanings in different knowledge-representation systems [»bracRJ10_1983]
Quote: using IS-A links for default properties is insufficient for complex concepts and interacts badly with cancellation [»bracRJ10_1983]
Quote: IS-A links may indicate subset/superset, a kind of, conceptual containment, role value restriction, or a set's characteristic type [»bracRJ10_1983]
Quote: the meaning of an IS-A link depends on understanding its nodes [»bracRJ10_1983]
Quote: IS-A between sets typically indicates subsets; IS-A between predicates typically indicates that A follows from B [»bracRJ10_1983]
Quote: IS-A links should be independent of inheritance; inheritance is a implementation issue [»bracRJ10_1983]
Quote: IS-A links between an individual and a generic indicate instantiation, set membership, predication, conceptual containment, and abstraction [»bracRJ10_1983]

Subtopic: problems with classification up

Quote: the same words may have different meanings when describing a class; a serious difficulty for recognition programs [»bongM_1967]
Quote: use Bongard patterns to test more complex, recognition programs

Related Topics up

Group: data type   (34 topics, 730 quotes)
Group: database model   (15 topics, 316 quotes)
Group: information   (46 topics, 1160 quotes)
Group: naming   (32 topics, 789 quotes)
Group: natural language   (16 topics, 539 quotes)
Group: object-oriented programming   (26 topics, 822 quotes)
Group: philosophy   (60 topics, 2323 quotes)
Group: philosophy of science   (10 topics, 406 quotes)
Group: sets   (7 topics, 148 quotes)

Topic: abstraction (62 items)
Topic: abstraction by common attributes (19 items)
Topic: decomposition of a system into levels (49 items)
Topic: definition by example (26 items)
Topic: fundamental concepts such as type, attributes, relationships are all the same (37 items)
Topic: hierarchical structures (46 items)
Topic: inheritance of properties (24 items)
Topic: meaning of words (21 items)
Topic: metaphysics and epistemology (99 items)
Topic: object-oriented classes (67 items)
Topic: object-oriented design (30 items)
Topic: object-oriented prototypes (39 items)
Topic: objects as a set of attributes (39 items)
Topic: problem of classifying information (42 items)
Topic: recognition (50 items)
Topic: reductionism (51 items)
Topic: set definition by extension or intension (18 items)
Topic: taxonomy
(16 items)

Updated barberCB 5/05
Copyright © 2002-2008 by C. Bradford Barber. All rights reserved.
Thesa is a trademark of C. Bradford Barber.