14 ideas
| 8250 | 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. |
| 15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
| Full Idea: The common feature of every designating term is that designation may change from state to state - thus it can be formalized by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3) | |
| A reaction: Specifying the objects sounds OK, but specifying states sounds rather tough. |
| 15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
| Full Idea: To first order modal logic (with quantification over objects) we can add a second kind of quantification, over intensions. An intensional object, or individual concept, will be modelled by a function from states to objects. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.3) |
| 15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
| Full Idea: Awareness logic enriched Hintikka's epistemic models with an awareness function, mapping each state to the set of formulas we are aware of at that state. This reflects some bound on the resources we can bring to bear. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) | |
| A reaction: [He cites Fagin and Halpern 1988 for this] |
| 15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
| Full Idea: In justification logics, the logics of knowledge are extended by making reasons explicit. A logic of proof terms was created, with a semantics. In this, mathematical truths are known for explicit reasons, and these provide a measure of complexity. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.6.1) |
| 11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
| Full Idea: Mathematics is typically extensional throughout (we write 3+2=2+3 despite the two terms having different meanings). ..Classical first-order logic is extensional by design since it primarily evolved to model the reasoning of mathematics. | |
| From: Melvin Fitting (Intensional Logic [2007], §1) |
| 11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
| Full Idea: λ-abstraction can be used to abstract and disambiguate a predicate. De re is [λx◊P(x)](f) - f has the possible-P property - and de dicto is ◊[λxP(x)](f) - possibly f has the P-property. Also applies to □. | |
| From: Melvin Fitting (Intensional Logic [2007], §3.3) | |
| A reaction: Compare the Barcan formula. Originated with Church in the 1930s, and Carnap 1947, but revived by Stalnaker and Thomason 1968. Because it refers to the predicate, it has a role in intensional versions of logic, especially modal logic. |
| 12708 | The soul is not a substance but a substantial form, the first active faculty [Leibniz] |
| Full Idea: The soul, properly and accurately speaking, is not a substance, but a substantial form, or the primitive form existing in substances, the first act, the first active faculty. | |
| From: Gottfried Leibniz (Letters to Fardella [1690], A6.4.1670), quoted by Daniel Garber - Leibniz:Body,Substance,Monad 2 | |
| A reaction: In all of Leibniz's many gropings towards what is at the heart of a unified object, I pounce on the phrase "the first active faculty" as the one that suits me. I take that to be a 'power'. It has two characteristics - it is active, and it is basic. |
| 8719 | There can be impossible and contradictory objects, if they can have properties [Meinong, by Friend] |
| Full Idea: Meinong (and Priest) leave room for impossible objects (like a mountain made entirely of gold), and even contradictory objects (such as a round square). This would have a property, of 'being a contradictory object'. | |
| From: report of Alexius Meinong (The Theory of Objects [1904]) by Michèle Friend - Introducing the Philosophy of Mathematics 6.8 | |
| A reaction: This view is only possible with a rather lax view of properties. Personally I don't take 'being a pencil' to be a property of a pencil. It might be safer to just say that 'round squares' are possible linguistic subjects of predication. |
| 8971 | There are objects of which it is true that there are no such objects [Meinong] |
| Full Idea: There are objects of which it is true that there are no such objects. | |
| From: Alexius Meinong (The Theory of Objects [1904]), quoted by Peter van Inwagen - Existence,Ontological Commitment and Fictions p.131 | |
| A reaction: Van Inwagen say this idea is 'infamous', but Meinong is undergoing a revival, and commitment to non-existent objects may be the best explanation of some ways of talking. |
| 8718 | Meinong says an object need not exist, but must only have properties [Meinong, by Friend] |
| Full Idea: Meinong distinguished between 'existing objects' and 'subsisting objects', and being an object does not imply existence, but only 'having properties'. | |
| From: report of Alexius Meinong (The Theory of Objects [1904]) by Michèle Friend - Introducing the Philosophy of Mathematics 6.8 | |
| A reaction: Meinong is treated as a joke (thanks to Russell), but this is good. "Father Christmas does not exist, but he has a red coat". He'd better have some sort of existy aspect if he is going to have a property. So he's 'an object'. 'Insubstantial'? |
| 7756 | Meinong said all objects of thought (even self-contradictions) have some sort of being [Meinong, by Lycan] |
| Full Idea: Meinong insisted (à la Anselm) that any possible object of thought - even a self-contradictory one - has being of a sort even though only a few such things are so lucky as to exist in reality as well. | |
| From: report of Alexius Meinong (The Theory of Objects [1904]) by William Lycan - Philosophy of Language Ch.1 | |
| A reaction: ['This idea gave Russell fits' says Lycan]. In the English-speaking world this is virtually the only idea for which Meinong is remembered. Russell (Idea 5409) was happy for some things to merely 'subsist' as well as others which could 'exist'. |
| 15781 | The objects of knowledge are far more numerous than objects which exist [Meinong] |
| Full Idea: The totality of what exists, including what has existed and what will exist, is infinitely small in comparison with the totality of Objects of knowledge. | |
| From: Alexius Meinong (The Theory of Objects [1904]), quoted by William Lycan - The Trouble with Possible Worlds 01 | |
| A reaction: This is rather profound, but the word 'object' doesn't help. I would say 'What we know concerns far more than what merely exists'. |
| 15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
| Full Idea: Definite descriptions pick out different objects in different possible worlds quite naturally. | |
| From: Melvin Fitting (Intensional Logic [2007], 3.4) | |
| A reaction: A definite description can pick out the same object in another possible world, or a very similar one, or an object which has almost nothing in common with the others. |