Type. Type-token distinction

The word "type" is used in many contexts (see Wikipedia, 2006a). The most important meaning for knowledge organization is probably:


"A type is a category of being. A human is a type of thing; a cloud is a type of thing; and so on. A particular instance of a type is called a token of that thing; so Socrates was a token of a human being, but is not any longer since he is dead. Likewise, the letter "A" is a token of the first letter of the Latin alphabet. " (Wikipedia, 2006b).

The type-token distinction was first drawn by Charles Sanders Peirce (1839-1914), between signs considered as abstract things (types) or as particular instances (tokens). Thus, for example, the number of words, the word count in a text (tokens) is much larger than the number of different words (types).


This distinctions is also used in bibliometrics (cf., Burrell, 2003; Chen & Leimkuhler, 1989; Egghe, 2003).






Burrell, Q. L. (2003). "Type/Token-Taken" informetrics: Some comments and further examples. Journal of the American Society for Information Science and Technology, 54(13), 1260-1263


Chen, Y. S. & Leimkuhler, F. F. (1989). A Type-Token identity in the Simon-Yule Model of text. Journal of the American Society for Information Science, 40(1), 45-53.


Egghe, L. (2003). Type/Token-Taken informetrics. Journal of the American Society for Information Science and Technology, 54(7), 603-610.


Wetzel, L. (2006). Types and tokens. In The Stanford Encyclopedia of Philosophy, ed. E. N.

Zalta. Stanford, CA: Center for the Study of Language and Information, Stanford

University. Retrieved November 16, 2006, from: http://plato.stanford.edu/entries/types-tokens/


Wikipedia, the free encyclopedia. (2006a). Type. http://en.wikipedia.org/wiki/Type


Wikipedia, the free encyclopedia. (2006b). Type (metaphysics). http://en.wikipedia.org/wiki/Type_%28metaphysics%29



See also: Natural kind; Species; Typology





Birger Hjørland

Last edited: 16-11-2006