|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.|
|Quine, Willard Van Orman
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Extensionality/Quine: ((x < y ) > ((y < x) > (x = y)) - i.e. a class is determined by its elements - (s) If x and y are subsets of each other, then they are the identical).
Extensionality axiom/EA (= E law)/Quine: classes that are consistent in their elements are equal - "x(x e y u x e z) > y = z - Abbreviation for "x(x e y u x e z) u (y e x z e x)] - Problem:> Individuals.
Extensionality axiom/Quine: (according to new identity definition: (y = z u y e w) > z e w.
Extensionality/Quine: is that what distinguishes attributes from classes - two attributes can be of different order and, therefore, certainly different, and yet be applied to the things, e.g. the attribute "j(j^x jy) where "j" has the order 1, an attribute solely of y - E.g. attribute "c(c^x cy), where "c" has the order 2, again an attribute solely of y, but one of the attributes has the order 2, the other has the order 3.
Wort und Gegenstand Stuttgart 1980
Theorien und Dinge Frankfurt 1985
Grundzüge der Logik Frankfurt 1978
Mengenlehre und ihre Logik Wiesbaden 1967
Die Wurzeln der Referenz Frankfurt 1989
Unterwegs zur Wahrheit Paderborn 1995
From a logical point of view Cambridge, Mass. 1953
Bezeichnung und Referenz
Zur Philosophie der idealen Sprache, J. Sinnreich (Hg), München 1982
Philosophie der Logik Bamberg 2005
Ontologische Relativität Frankfurt 2003