|Extensionality, philosophy: (also extensionality principle, extensionality thesis) an attempt to make the language distinct by taking complete sets of denoted objects as the meaning of the referring words. See also extensions, intensions, extensional language, ambiguity, propositional attitudes._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. |
Extensionality/Homogeneity: a context is extensional if the possible world equivalent relation does not have to be divided more finely than the designation equivalent relation: (Problem: the equivalence of "Snow is white" and "Grass is green") - therefore, the relationship between designated inferences and inferetial role of freestanding sentences is not homogeneous - it is not sufficient to know whether the sentences are true inferences - (because sentences are no inferences at all) - therefore we need a different extensionality at the top level: a sentential context with embedded phrases is extensional in the sense of being part homogeneous iff the substitution of statements with the same inferential role never changes the inferential role of the contained sentence.
This is not always the case: E.g. the role of the expression "S claims that p" does not depend on the role p has for the speaker, but on the role he has for S._____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. The note [Author1]Vs[Author2] or [Author]Vs[term] is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition.
Making it exlicit. Reasoning, Representing, and Discursive Commitment, Cambridge/MA 1994
Expressive Vernunft Frankfurt 2000
Articulating reasons. An Introduction to Inferentialism, Cambridge/MA 2001
Begründen und Begreifen Frankfurt 2001