Extension Identity

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The extensional identity refers to an identity under certain conditions of the given expressions that the properties extensional and coextensive meet.

Let A and B be arbitrary terms. Then A is called extensionally identical to B if and only if they reflect the same class of individuals.

They thus meet the condition that they contain the same elements or are of the same scope.

If two concepts are identical in terms of their intent (internal identity), they are also extensionally identical.

Summary:

  • Two terms are identically when the connotation and concept extent match, ie if they are intensional and extensional identical identical.
  • Note: With this it is clear that there is also the possibility that two terms are intensionally different but extensionally the same.

Example:

  • In some Bavarian villages it is said that the CSU local association and the rifle club have exactly the same members, even though both associations have different statutes and intentions. So these two terms are extensional, but not intensional.