Extensional and intensional definitions: Difference between revisions

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An extensional definition gives meaning to a term by specifying its [[Extension (semantics)|extension]], that is, every [[object (philosophy)|object]] that falls under the definition of the term in question.

ForgetFor example, an extensional definition of the term "nation of the world" might be given by [[List of sovereign states|listing all of the nations of the world]], or by giving some other means of recognizing the members of the corresponding class. An explicit listing of the extension, which is only possible for [[finite sets]] and only practical for relatively [[Small set (category theory)|small sets]], is a type of ''[[enumerative definition]]''.

Extensional definitions are used when listing examples would give more applicable information than other types of definition, and where listing the members of a [[set (mathematics)|set]] tells the questioner enough about the nature of that set.