Philosophy Dictionary of ArgumentsHome
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| 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. | |||
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A. Prior on Extensionality - Dictionary of Arguments
I 48 Extensionality: "Law of extensionality": if the sentences S1 and S2 have the same truth value, then, each composite sentence that differs only in that it has S1 as a subset , where the other has S2 as a subset, also the same truth value. >Truth values, >Truth, >Extensions, >Clauses. PriorVs: one can count mixed constructions like "__is green and__" also "__believes that__" into the same category as the simple. - If the law of extensionality is true, then must "grass is pink" and "grass is purple" be the same thought. >Thoughts, >Thought/Frege, cf. >Fregean meaning, >Fregean sense. Solution: "x thinks, grass is pink" is not a compound sentence with "grass is pink" as a component. Cf. >Compositionality, >Thinking, >Sentences, >Propositions. I 50 Extensionality/Prior: Lesniewski/Lukasiewicz: if one drops the E, one must admit that some propositions are neither true nor false. >St. Lesniewski, >J. Lukasiewicz. PriorVsExtensionality: truth value of a statement depends not only on its truth value. (Circular). >Circular reasoning. I 93 Law of extensionality: propositions with the same truth value are identical. >Identity, cf. >Equivalence. I 139 Extensionality/Prior: "cause", "bring about" seems to be the most extensional operator: the one who brings p about, brings everything into existence ipso facto, what is equivalent with p. Cf. >Command/Prior. But it does not bring into existence what it contains (entailment, asymmetric implication ): E.g. someone is caught by the FBI and a communist, but that does not bring about, that he is a communist. >Causation, >Entailment/Prior._____________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. Translations: Dictionary of Arguments The note [Concept/Author], [Author1]Vs[Author2] or [Author]Vs[term] resp. "problem:"/"solution:", "old:"/"new:" and "thesis:" is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition. |
Pri I A. Prior Objects of thought Oxford 1971 Pri II Arthur N. Prior Papers on Time and Tense 2nd Edition Oxford 2003 |
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> Counter arguments against Prior
> Counter arguments in relation to Extensionality
Ed. Martin Schulz, access date 2024-04-18