Outline of knowledge

Last updated May 12, 2025

The following outline is provided as an overview of and topical guide to knowledge:

Knowledge – familiarity with someone or something, which can include facts, information, descriptions, and/or skills acquired through experience or education. It can refer to the theoretical or practical understanding of a subject. It can be implicit (as with practical skill or expertise) or explicit (as with the theoretical understanding of a subject); and it can be more or less formal or systematic.^[1]

Types of knowledge

By form

A priori and a posteriori knowledge – these terms are used with respect to reasoning (epistemology) to distinguish necessary conclusions from first premises.
- A priori knowledge or justification – knowledge that is independent of experience, as with mathematics, tautologies ("All bachelors are unmarried"), and deduction from pure reason (e.g., ontological proofs).^[3]
- A posteriori knowledge or justification – knowledge dependent on experience or empirical evidence, as with most aspects of science and personal knowledge.
Descriptive knowledge – also called declarative knowledge or propositional knowledge, it is the type of knowledge that is, by its very nature, expressed in declarative sentences or indicative propositions (e.g., "Capybaras are rodents", or "It is raining"). This is distinguished from what is commonly known as "know-how" or procedural knowledge (the knowledge of how, and especially how best, to perform some task), and "knowing of", or knowledge by acquaintance (the knowledge of something's existence).
Experience – knowledge or mastery of an event or subject gained through involvement in or exposure to it.^[4]
- Empirical evidence – also referred to as empirical data, empirical knowledge, and sense experience, it is a collective term for the knowledge or source of knowledge acquired by means of the senses, particularly by observation and experimentation.^[5] After Immanuel Kant, it is common in philosophy to call the knowledge thus gained a posteriori knowledge. This is contrasted with a priori knowledge, the knowledge accessible from pure reason alone.
- Experiential knowledge – knowledge gained through experience.
Explicit knowledge – knowledge that can be readily articulated, codified, accessed and verbalized.^[6] It can be easily transmitted to others. Most forms of explicit knowledge can be stored in certain media. The information contained in encyclopedias and textbooks are good examples of explicit knowledge.
Extelligence – term coined by Ian Stewart and Jack Cohen in their 1997 book Figments of Reality. They define it as the cultural capital that is available to us in the form of external media (e.g., tribal legends, folklore, nursery rhymes, books, videotapes, CD-ROMs, etc.).
Knowledge by acquaintance – according to Bertrand Russell, knowledge by acquaintance is obtained through a direct causal (experience-based) interaction between a person and the object that person is perceiving. Sense-data from that object are the only things that people can ever become acquainted with; they can never truly KNOW the physical object itself. The distinction between "knowledge by acquaintance" and "knowledge by description" was promoted by Russell (notably in his 1905 paper On Denoting). Russell was extremely critical of the equivocal nature of the word "know", and believed that the equivocation arose from a failure to distinguish between the two fundamentally different types of knowledge.
Libre knowledge – knowledge released in such a way that users are free to read, listen to, watch, or otherwise experience it; to learn from or with it; to copy, adapt and use it for any purpose; and to share the work (unchanged or modified). Whilst shared tacit knowledge is regarded as implicitly libre, (explicit) libre knowledge is defined as a generalisation of the libre software definition.
Procedural knowledge – also known as imperative knowledge, it is the knowledge exercised in the performance of some task. Commonly referred to as "knowing-how" and opposed to "knowing-that" (descriptive knowledge).
Tacit knowledge – kind of knowledge that is difficult to transfer to another person by means of writing it down or verbalizing it. For example, that London is in the United Kingdom is a piece of explicit knowledge that can be written down, transmitted, and understood by a recipient. However, the ability to speak a language, knead dough, play a musical instrument or design and use complex equipment requires all sorts of knowledge that is not always known explicitly, even by expert practitioners, and which is difficult or impossible to explicitly transfer to other users.

By scope

Common knowledge – knowledge that is known by everyone or nearly everyone, usually with reference to the community in which the term is used.
Customer knowledge – knowledge for, about, or from customers.
Domain knowledge – valid knowledge used to refer to an area of human endeavour, an autonomous computer activity, or other specialized discipline.
Foundational knowledge – the knowledge necessary for understanding or usefully applying further knowledge in a field.
General knowledge – information that has been accumulated over time through various mediums.^[7] This definition excludes highly specialized learning that can only be obtained with extensive training and information confined to a single medium. General knowledge is an important component of crystallized intelligence and is strongly associated with general intelligence, and with openness to experience.^[8]
Metaknowledge – knowledge about knowledge. Bibliographies are a form of metaknowledge. Patterns within scientific literature is another.
Mutual knowledge – Information known by all participatory agents
Self-knowledge – information that an individual draws upon when finding an answer to the question "What am I like?".
Traditional knowledge – knowledge systems embedded in the cultural traditions of regional, indigenous, or local communities. Traditional knowledge includes types of knowledge about traditional technologies of subsistence (e.g. tools and techniques for hunting or agriculture), midwifery, ethnobotany and ecological knowledge, traditional medicine, celestial navigation, ethnoastronomy, the climate, and others. These kinds of knowledge, crucial for subsistence and survival, are generally based on accumulations of empirical observation and on interaction with the environment.
- Traditional ecological knowledge

Structure of knowledge

Taxonomies

Types of subject taxonomies
Specific taxonomies of knowledge
- Figurative System of Human Knowledge
- Propædia – first of three parts of the 15th edition of Encyclopædia Britannica , presenting its Outline of Knowledge.
- Tree of Knowledge System

Types of bodies of recorded knowledge

Academic disciplines – branch of knowledge that is taught and researched as part of higher education. A scholar's discipline is commonly defined and recognized by the university faculties and learned societies to which he or she belongs and the academic journals in which he or she publishes research. However, no formal criteria exist for defining an academic discipline.
Body of knowledge (BOK) – specialized term in knowledge representation meaning the set of concepts, terms and activities that make up a professional domain, as defined by the relevant learned society or professional association.
Curriculi – plural of curriculum, which means the totality of student experiments that occur in the educational process.^[9]^[10] The term often refers specifically to a planned sequence of instruction, or to a view of planned student's experiences in terms of the educator's or school's instructional goals. Curricula may be tightly standardized, or may include a high level of instructor or learner autonomy.^[11] Many countries have national curricula in primary and secondary education, such as the United Kingdom's National Curriculum.
Encyclopedias – type of reference work or compendium holding a comprehensive summary of information from either all branches of knowledge or a particular branch of knowledge.^[12] Encyclopedias are divided into articles or entries, which are usually accessed alphabetically by article name.^[13] Encyclopedia entries are longer and more detailed than those in most dictionaries.^[13] Generally speaking, unlike dictionary entries, which focus on linguistic information about words, encyclopedia articles focus on factual information concerning the subject for which the article is named.^[14]^[15]^[16]^[17]
Knowledge base
- Personal knowledge base
Knowledge commons
Libraries – a library is a collection of sources of information and similar resources, made accessible to a defined community for reference or borrowing.^[18] It provides physical or digital access to material, and may be a physical building or room, or a virtual space, or both.^[19] A library's collection can include books, periodicals, newspapers, manuscripts, films, maps, prints, documents, microform, CDs, cassettes, videotapes, DVDs, Blu-ray Discs, e-books, audiobooks, databases, and other formats. Libraries range in size from a few shelves of books to several million items.

Specific bodies of recorded knowledge, by type

Specific BOKs (bodies of knowledge, in the context of the knowledge representation field)
- Canadian IT Body of Knowledge
- Civil Engineering Body of Knowledge
- Common Body of Knowledge
- Enterprise Architecture Body of Knowledge
- Geographic Information Science and Technology Body of Knowledge
- Project Management Body of Knowledge
- Software Engineering Body of Knowledge
- Data Management Body of Knowledge
Specific encyclopedias
- Bibliography of encyclopedias
- List of encyclopedias by branch of knowledge
- List of encyclopedias by language
- List of historical encyclopedias
- List of online encyclopedias
  - Wikipedia – largest encyclopedia in the world. It is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its more than 20 million articles (over 6.89 million in English) have been written collaboratively by volunteers around the world. Almost all of its articles can be edited by anyone with access to the site,^[20] and it has about 100,000 regularly active contributors.^[21]
Specific knowledge bases
- Knowledge Vault – knowledge base created by Google. As of 2014, it contained 1.6 billion facts which had been collated automatically from the Internet.

Epistemology (philosophy of knowledge)

Epistemology – philosophy of knowledge. It is the study of knowledge and justified belief. It questions what knowledge is and how it can be acquired, and the extent to which knowledge pertinent to any given subject or entity can be acquired. Much of the debate in this field has focused on the philosophical analysis of the nature of knowledge and how it relates to connected notions such as truth, belief, and justification.

DIKW pyramid – theoretical model of the relationship between data, information, knowledge, and wisdom
Knowledge neglect – failure to apply knowledge
Theory of knowledge (IB course) – a course related to epistemology

Management of knowledge

Knowledge management

Chief knowledge officer
Knowledge balance sheet
Knowledge ecosystem
Knowledge mobilization
Knowledge organization (effort)
- Knowledge organization system
Knowledge organization (company or agency)
Knowledge transfer
Knowledge worker

Obtaining knowledge

Methods of obtaining knowledge

Exploration
Learning
- Autodidactism – self-education; act of self-directed learning about a subject or subjects in which one has had little to no formal education.
- Reading
- Studying
- Knowledge building
  - Knowledge building communities

Knowledge storage

Knowledge can be stored in:

Books
Knowledge bases
- Ontology – formal naming and definition of the types, properties, and interrelationships of the entities that really or fundamentally exist for a particular domain of discourse.
  - Commonsense knowledge base – database containing all the general knowledge that most people possess, represented in a way that it is available to artificial intelligence programs that use natural language or make inferences about the ordinary world.
  - Knowledge graph – another name for ontology
Knowledge representation (AI)
- Body of knowledge (BOK) – complete set of concepts, terms and activities that make up a professional domain, as defined by the relevant learned society or professional association
Libraries
Memory

Knowledge retrieval

Knowledge retrieval – Stored knowledge can be retrieved by:

Knowledge engine
- WolframAlpha – computational knowledge engine or answer engine developed by Wolfram Research
- Knowledge Engine (Wikimedia Foundation) – search engine project by the Wikimedia Foundation
- Google Search – powered by:
  - Google Knowledge Graph – knowledge base used by Google to enhance its search engine's search results with semantic search information gathered from a wide variety of sources
Knowledge discovery
Reading

Imparting knowledge

Communication – purposeful activity of information exchange between two or more participants in order to convey or receive the intended meanings through a shared system of signs and semiotic rules. The basic steps of communication are the forming of communicative intent, message composition, message encoding, transmission of signal, reception of signal, message decoding and interpretation of the message by the recipient. Examples of methods of communication used to impart knowledge include: Writing and Publishing.
Education – process of facilitating learning.
- Educational methods:
  - Storytelling
  - Discussion
  - Teaching
  - Training
  - Directed research
Knowledge sharing – activity through which knowledge (namely, information, skills, or expertise) is exchanged among people, friends, families, communities (Wikipedia), or organizations.^[22]^[23]

History of the knowledge of humanity

Knowledge and society

Economics of knowledge

Politics of knowledge

Access to Knowledge movement
Knowledge assessment methodology
Knowledge society
Local knowledge problem
Open access
- Berlin Declaration on Open Access to Knowledge in the Sciences and Humanities
Scientia potentia est – Latin for "knowledge is power".
The Cost of Knowledge protest
World Brain

Sociology of knowledge

Knowledge technology

Knowledge of humanity

The world's knowledge (knowledge possessed by human civilization):^[24]^[25]^[26]^[27]

Organizations

Publications

Books

A Guide for the Perplexed by E. F. Schumacher (critique of materialist scientism and an exploration of the nature and organization of knowledge).
Knowledge and Its Limits
Human Knowledge: Its Scope and Limits by Bertrand Russell, a founder of analytic philosophy.

Journals

References

↑ "knowledge (knowl·edge)". Oxford Dictionaries Online. Archived from the original on Jul 14, 2010.
↑ Sommers, Tamler (March 1, 2003). "An Interview with Galen Strawson". The Believer . No. 1.
↑ Galen Strawson has stated that an a priori argument is one in which "you can see that it is true just lying on your couch. You don't have to get up off your couch and go outside and examine the way things are in the physical world. You don't have to do any science."^[2]
↑ Compare various contemporary definitions given in the OED (2nd edition, 1989): "[...] 3. The actual observation of facts or events, considered as a source of knowledge.[...] 4. a. The fact of being consciously the subject of a state or condition, or of being consciously affected by an event. [...] b. In religious use: A state of mind or feeling forming part of the inner religious life; the mental history (of a person) with regard to religious emotion. [...] 6. What has been experienced; the events that have taken place within the knowledge of an individual, a community, mankind at large, either during a particular period or generally. [...] 7. a. Knowledge resulting from actual observation or from what one has undergone. [...] 8. The state of having been occupied in any department of study or practice, in affairs generally, or in the intercourse of life; the extent to which, or the length of time during which, one has been so occupied; the aptitudes, skill, judgement, etc. thereby acquired."
↑ Pickett 2011 , p. 585
↑ Helie, Sebastien; Sun, Ron (2010). "Incubation, Insight, and Creative Problem Solving: A Unified Theory and a Connectionist Model". Psychological Review. 117 (3): 994–1024. doi:10.1037/a0019532. PMID 20658861.
↑ "general knowledge". Cambridge English Dictionary. Retrieved 2019-08-24.
↑ Bates, T. C.; Shieles, A. (2003). "Crystallized Intelligence as a product of Speed and Drive for Experience: The Relationship of Inspection Time and Openness to g and Gc". Intelligence. 31 (3): 275–287. doi:10.1016/S0160-2896(02)00176-9.
↑ Kelly 2009, p. 13.
↑ Wiles, Jon (2008). Leading Curriculum Development. p. 2. ISBN 9781412961417.
↑ Adams 2003, pp. 33–34.
↑ "Encyclopedia". Archived from the original on 2007-08-03. Glossary of Library Terms. Riverside City College, Digital Library/Learning Resource Center. Retrieved on: November 17, 2007.
1 2 Hartmann, R. R. K.; James, Gregory; Gregory James (1998). Dictionary of Lexicography. Routledge. p. 48. ISBN 978-0-415-14143-7 . Retrieved July 27, 2010.
↑ Béjoint, Henri (2000). Modern Lexicography, pp. 30–31. Oxford University Press. ISBN 0-19-829951-6
↑ "Encyclopaedia". Encyclopædia Britannica. Retrieved July 27, 2010. An English lexicographer, H.W. Fowler, wrote in the preface to the first edition (1911) of The Concise Oxford Dictionary of Current English language that a dictionary is concerned with the uses of words and phrases and with giving information about the things for which they stand only so far as current use of the words depends upon knowledge of those things. The emphasis in an encyclopedia is much more on the nature of the things for which the words and phrases stand.
↑ Hartmann, R. R. K.; Gregory James (1998). Dictionary of Lexicography. Routledge. p. 49. ISBN 978-0-415-14143-7 . Retrieved July 27, 2010. In contrast with linguistic information, encyclopedia material is more concerned with the description of objective realities than the words or phrases that refer to them. In practice, however, there is no hard and fast boundary between factual and lexical knowledge.
↑ Cowie, Anthony Paul (2009). The Oxford History of English Lexicography, Volume I. Oxford University Press. p. 22. ISBN 978-0-415-14143-7 . Retrieved August 17, 2010. An 'encyclopedia' (encyclopaedia) usually gives more information than a dictionary; it explains not only the words but also the things and concepts referred to by the words.
↑ "Library". Merriam-Webster Dictionary.
↑ "Library ... collection of books, public or private; room or building where these are kept; similar collection of films, records, computer routines, etc. or place where they are kept; series of books issued in similar bindings as set."--Allen, R. E., ed. (1984) The Pocket Oxford Dictionary of Current English. Oxford: Clarendon Press; p. 421
↑ "Wikipedia's Jimmy Wales Speaks Out On China And Internet Freedom". Huffington Post . Retrieved 2011-09-24. Currently Wikipedia, Facebook and Twitter remain blocked in China
↑ "'Technology can topple tyrants': Jimmy Wales an eternal optimist". Sydney Morning Herald . 7 November 2011.
↑ Bukowitz, Wendi R.; Williams, Ruth L. (1999). The Knowledge Management Fieldbook. FT Press. ISBN 978-0273638827.
↑ Serban, Andreea M.; Luan, Jing (Spring 2002). "An Overview of Knowledge Management" (PDF). New Directions for Institutional Research. University of Kentucky. Retrieved 17 April 2013.
↑ "Part Ten. Branches of Knowledge". The New Encyclopædia Britannica, 15th edition. Vol. Propædia. Chicago: Encyclopædia Britannica Inc. 2007. p. 475-523.
↑ Adler, Mortimer J. (2007). "Circle of Learning". The New Encyclopædia Britannica, 15th edition. Vol. Propædia. Chicago: Encyclopædia Britannica Inc. p. 5-8.
↑ Cohen, Eliel (2021). "The boundary lens: theorising academic actitity". The University and its Boundaries: Thriving or Surviving in the 21st Century 1st Edition. New York, New York: Routledge. pp. 14–41. ISBN 978-0367562984.
↑ Revised Field of Science and Technology (FOS) Classification in the Frascati Manual, OECD

Works cited

Adams, Kathy L.; Adams, Dale E. (2003). Urban Education: A Reference Handbook . ABC-CLIO. pp. 31–32. ISBN 9781576073629.
Kelly, A.V. (2009). The Curriculum: theory and practice (6th ed.). ISBN 9781847872746.
Pickett, Joseph P., ed. (2011). The American Heritage Dictionary of the English Language (5th ed.). Houghton Mifflin. ISBN 978-0-547-04101-8.

External links

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[1] "knowledge (knowl·edge)". Oxford Dictionaries Online. Archived from the original on Jul 14, 2010.

[2] Sommers, Tamler (March 1, 2003). "An Interview with Galen Strawson". The Believer . No. 1.

[3] Galen Strawson has stated that an a priori argument is one in which "you can see that it is true just lying on your couch. You don't have to get up off your couch and go outside and examine the way things are in the physical world. You don't have to do any science."^[2]

[4] Compare various contemporary definitions given in the OED (2nd edition, 1989): "[...] 3. The actual observation of facts or events, considered as a source of knowledge.[...] 4. a. The fact of being consciously the subject of a state or condition, or of being consciously affected by an event. [...] b. In religious use: A state of mind or feeling forming part of the inner religious life; the mental history (of a person) with regard to religious emotion. [...] 6. What has been experienced; the events that have taken place within the knowledge of an individual, a community, mankind at large, either during a particular period or generally. [...] 7. a. Knowledge resulting from actual observation or from what one has undergone. [...] 8. The state of having been occupied in any department of study or practice, in affairs generally, or in the intercourse of life; the extent to which, or the length of time during which, one has been so occupied; the aptitudes, skill, judgement, etc. thereby acquired."

[5] Pickett 2011 , p. 585

[6] Helie, Sebastien; Sun, Ron (2010). "Incubation, Insight, and Creative Problem Solving: A Unified Theory and a Connectionist Model". Psychological Review. 117 (3): 994–1024. doi:10.1037/a0019532. PMID 20658861.

[7] "general knowledge". Cambridge English Dictionary. Retrieved 2019-08-24.

[8] Bates, T. C.; Shieles, A. (2003). "Crystallized Intelligence as a product of Speed and Drive for Experience: The Relationship of Inspection Time and Openness to g and Gc". Intelligence. 31 (3): 275–287. doi:10.1016/S0160-2896(02)00176-9.

[FOOTNOTEKelly200913-9] Kelly 2009, p. 13.

[10] Wiles, Jon (2008). Leading Curriculum Development. p. 2. ISBN 9781412961417.

[FOOTNOTEAdams200333–34-11] Adams 2003, pp. 33–34.

[12] "Encyclopedia". Archived from the original on 2007-08-03. Glossary of Library Terms. Riverside City College, Digital Library/Learning Resource Center. Retrieved on: November 17, 2007.

[DOLencyclopedia-13] 1 2 Hartmann, R. R. K.; James, Gregory; Gregory James (1998). Dictionary of Lexicography. Routledge. p. 48. ISBN 978-0-415-14143-7 . Retrieved July 27, 2010.

[bejoint-14] Béjoint, Henri (2000). Modern Lexicography, pp. 30–31. Oxford University Press. ISBN 0-19-829951-6

[EB-15] "Encyclopaedia". Encyclopædia Britannica. Retrieved July 27, 2010. An English lexicographer, H.W. Fowler, wrote in the preface to the first edition (1911) of The Concise Oxford Dictionary of Current English language that a dictionary is concerned with the uses of words and phrases and with giving information about the things for which they stand only so far as current use of the words depends upon knowledge of those things. The emphasis in an encyclopedia is much more on the nature of the things for which the words and phrases stand.

[DOLei-16] Hartmann, R. R. K.; Gregory James (1998). Dictionary of Lexicography. Routledge. p. 49. ISBN 978-0-415-14143-7 . Retrieved July 27, 2010. In contrast with linguistic information, encyclopedia material is more concerned with the description of objective realities than the words or phrases that refer to them. In practice, however, there is no hard and fast boundary between factual and lexical knowledge.

[OHEL22-17] Cowie, Anthony Paul (2009). The Oxford History of English Lexicography, Volume I. Oxford University Press. p. 22. ISBN 978-0-415-14143-7 . Retrieved August 17, 2010. An 'encyclopedia' (encyclopaedia) usually gives more information than a dictionary; it explains not only the words but also the things and concepts referred to by the words.

[18] "Library". Merriam-Webster Dictionary.

[19] "Library ... collection of books, public or private; room or building where these are kept; similar collection of films, records, computer routines, etc. or place where they are kept; series of books issued in similar bindings as set."--Allen, R. E., ed. (1984) The Pocket Oxford Dictionary of Current English. Oxford: Clarendon Press; p. 421

[anyone-20] "Wikipedia's Jimmy Wales Speaks Out On China And Internet Freedom". Huffington Post . Retrieved 2011-09-24. Currently Wikipedia, Facebook and Twitter remain blocked in China

[21] "'Technology can topple tyrants': Jimmy Wales an eternal optimist". Sydney Morning Herald . 7 November 2011.

[2KMF-22] Bukowitz, Wendi R.; Williams, Ruth L. (1999). The Knowledge Management Fieldbook. FT Press. ISBN 978-0273638827.

[5OKM-23] Serban, Andreea M.; Luan, Jing (Spring 2002). "An Overview of Knowledge Management" (PDF). New Directions for Institutional Research. University of Kentucky. Retrieved 17 April 2013.

[Propædia-24] "Part Ten. Branches of Knowledge". The New Encyclopædia Britannica, 15th edition. Vol. Propædia. Chicago: Encyclopædia Britannica Inc. 2007. p. 475-523.

[PropædiaCircle-25] Adler, Mortimer J. (2007). "Circle of Learning". The New Encyclopædia Britannica, 15th edition. Vol. Propædia. Chicago: Encyclopædia Britannica Inc. p. 5-8.

[cohen2021-26] Cohen, Eliel (2021). "The boundary lens: theorising academic actitity". The University and its Boundaries: Thriving or Surviving in the 21st Century 1st Edition. New York, New York: Routledge. pp. 14–41. ISBN 978-0367562984.

[27] Revised Field of Science and Technology (FOS) Classification in the Frascati Manual, OECD

[1]

[3]

[4]

[5]

[6]

[7]

[8]

[9]

[10]

[11]

[12]

[13]

[14]

[15]

[16]

[17]

[18]

[19]

[20]

[21]

[22]

[23]

[24]

[25]

[26]

[27]

[2]