Combining Texts

Ideas for 'Frege's Theory of Numbers', 'The Theory of Objects' and 'Barcan Formulae'

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2 ideas

4. Formal Logic / D. Modal Logic ML / 7. Barcan Formula
Barcan:nothing comes into existence; Converse:nothing goes out; Both:domain is unchanging [Vervloesem]
     Full Idea: Intuitively, the Barcan formula says that nothing comes into existence when moving from a possible world to an alternative world. The converse says that nothing goes out of existence. Together they say the domain of quantification is fixed for all worlds.
     From: Koen Vervloesem (Barcan Formulae [2010])
     A reaction: Stated so clearly, they sound absurd. The sensible idea, I suppose, is that you can refer to all the things from any world, but that doesn't mean they are possible. Shades of Meinong. 'Square circles' are not possible.
4. Formal Logic / E. Nonclassical Logics / 6. Free Logic
So-called 'free logic' operates without existence assumptions [Meinong, by George/Van Evra]
     Full Idea: Meinong has recently been credited with inspiring 'free logic': a logic without existence assumptions.
     From: report of Alexius Meinong (The Theory of Objects [1904]) by George / Van Evra - The Rise of Modern Logic 8
     A reaction: This would appear to be a bold escape from the quandries concerning the existential implications of quantifiers. I immediately find it very appealing. It seems to spell disaster for the Quinean program of deducing ontology from language.