World Library  
Flag as Inappropriate
Email this Article

Type–token distinction

Article Id: WHEBN0014934822
Reproduction Date:

Title: Type–token distinction  
Author: World Heritage Encyclopedia
Language: English
Subject: Analytic philosophy, Metaphysics, John Searle, G. E. Moore, Willard Van Orman Quine
Publisher: World Heritage Encyclopedia

Type–token distinction

Although this flock is made of the same type of bird, each individual bird is a different token. (50 MB video of a flock of birds in Rome)

In disciplines such as logic, linguistics, metalogic, typography, and computer programming, the type–token distinction is a distinction that separates a descriptive concept from objects that instantiate the concept, seen as particular instances of it. For example, the sentence "the bicycle is in the garage" refers to a token of the type named "bicycle", while the sentence "the bicycle is becoming more popular" refers to the type.

This distinction in computer programming between classes and objects is similar, though in this context, "class" may refer to a set of objects (with class-level attribute or operations) rather than a description of an object in the set.

The words type, concept, property, quality, feature and attribute are all used in describing things. Some verbs fit some of these words better than others. E.g. You might say a rose bush is a plant that instantiates the type(s), or embodies the concept(s), or exhibits the properties, or possesses the qualities, features or attributes “thorny”, “flowering” and “bushy”. The term "property" is used ambiguously to mean property type (height in feet) and/or property instance (1.74). The term "concept" is probably used more often for the property type (height in feet) than the property instance.

Types like "thorny" are often understood ontologically as concepts. Types exist in descriptions of objects, but not as tangible physical objects. A type may have many tokens. However, types are not directly producible as tokens are. One can show someone a particular bicycle, but cannot show someone the type "bicycle", as in "the bicycle is popular." It is often presumed that tokens exist in space and time as concrete physical objects. But tokens of the types "thought", "tennis match", "government" and "act of kindness" don't fit this presumption.

Clarity requires us to distinguish between abstract "types" and the "tokens" or things that embody or exemplify types. If we hear that two people "have the same car", we may conclude that they have the same type of car (e.g. the same make and model), or the same particular token of the car (e.g. they share a single vehicle). The distinction is useful in other ways, during discussion of language.


There is a related distinction very closely connected with the type-token distinction. This distinction is the distinction between an object, or type of object, and an occurrence of it. In this sense, an occurrence is not necessarily a token. Quine discovered this distinction. However, he only gave what he called an "artificial, but convenient and adequate definition" as "an occurrence of x in y is an initial segment of y ending in x".[1] Quine's proposed "definition", known as The Prefix Proposal, has not received the attention it deserves, but at least one counter-proposal has been formulated.[2]

Considering the sentence: "A rose is a rose is a rose". We may equally correctly state that there are eight or three words in the sentence. There are, in fact, three word types in the sentence: "rose", "is" and "a". There are eight word tokens in a token copy of the line. The line itself is a type. There are not eight word types in the line. It contains (as stated) only the three word types, 'a,' 'is' and 'rose,' each of which is unique. So what do we call what there are eight of? They are occurrences of words. There are three occurrences of the word type 'a,' two of 'is' and three of 'rose'.

The need to distinguish tokens of types from occurrences of types arises, not just in linguistics, but whenever types of things have other types of things occurring in them.[3] Reflection on the simple case of occurrences of numerals is often helpful.


In typography, the type–token distinction is used to determine the presence of a text printed by movable type:[4]

The defining criteria which a typographic print has to fulfill is that of the type identity of the various letter forms which make up the printed text. In other words: each letter form which appears in the text has to be shown as a particular instance ("token") of one and the same type which contains a reverse image of the printed letter.

See also


  1. ^ Quine, Quiddities
  2. ^ See the WorldHeritage article "Occurrences of numerals"
  3. ^ Stanford Encyclopedia of Philosophy, Types and Tokens
  4. ^ Brekle, Herbert E.: Die Prüfeninger Weiheinschrift von 1119. Eine paläographisch-typographische Untersuchung, Scriptorium Verlag für Kultur und Wissenschaft, Regensburg 2005, ISBN 3-937527-06-0, p. 23


  • Baggin J., and Fosl, P. (2003) The Philosopher's Toolkit. Blackwell: 171-73. ISBN 978-0-631-22874-5.
  • Peper F., Lee J., Adachi S.,Isokawa T. (2004) Token-Based Computing on Nanometer Scales, Proceeding of the ToBaCo 2004 Workshop on Token Based Computing, Vol.1 pp. 1–18.

External links

This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.