Equipollence
Äquipollenz (from Latin aequipollens asserted = matter) can with equal validity or equal thickness to be translated.
The term is used in traditional logic, set theory, law and linguistics. Another frequently used synonym is "coextensionality".
Equipollence in traditional logic
In traditional logic, equipollence denotes the logical equivalence of concepts or judgments. In addition, one knows a conclusion through equipollence. A specific concept of equipollence can be found in Leibniz .
Equipollent terms
In traditional logic , equipollent denotes terms that are the same in scope, or more modern: terms with the same extension, i.e. H. Terms that have the same extension but different intensions.
Example: The terms morning star and evening star have the same extension / the same reference object ( Frege describes this as the meaning of a term), namely the planet Venus , but a different intension (Frege calls this the meaning / type of being given): the The morning star is the star that shines first in the morning sky, whereas the evening star is the star that shines first in the evening sky (see also Frege's essay On Meaning and Meaning ).
Equipollent statements (judgments)
Two statements are considered to be equipollent if they reflect the same facts in different ways.
Example: Everyone is mortal and no person is not mortal .
Example: Meier kills Miller and Miller is killed by Meier .
End through equipollence (equipollence law)
An immediate conclusion through equipollence (also: equipollence law) is the same as a conclusion through opposition or obversion .
Equipollence in the Leibniz sense
Leibniz understands equipollence as the "mutual substitutability of concepts and judgments without prejudice to their truth value".
Equipollence in the sense of set theory
In set theory, instead of the equivalence of sets, the term equipollence is sometimes used.
Equipollence in Linguistics
In linguistics, equipollence sometimes means the logical equality of two opposite concepts that are not just mutual negation.
Examples: up and down ; City and country .