10 ideas
| 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. |
| 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. |
| 15677 | Moral right is linked to validity and truth, so morality is a matter of knowledge, not an expression of values [Habermas, by Finlayson] |
| Full Idea: According to discourse ethics moral rightness is internally linked to validity and is analogous to truth: ..thus Habermas takes himself to have shown that morality is a matter of knowledge, rather than the expression of contingently held values. | |
| From: report of Jürgen Habermas (Moral Consciousness and Communicative Action [1990]) by James Gordon Finlayson - Habermas Ch.7:102 | |
| A reaction: I can immediately hear Nietzsche asking why you place such a high value on knowledge. Personally I don't assume that values must be 'contingent'. The Aristotelian tradition sees necessary values in facts about human nature. |
| 15671 | Move from individual willing of a general law, to willing norms agreed with other people [Habermas] |
| Full Idea: The emphasis shifts from what each can will without contradiction to be a general law, to what all can will in agreement to be a universal norm. | |
| From: Jürgen Habermas (Moral Consciousness and Communicative Action [1990], p.67), quoted by James Gordon Finlayson - Habermas Ch.5:69 | |
| A reaction: This strikes me as being very close to Scanlon's contractualism. As expressed here, it sounds more vulnerable than Kant's full universality to the problem of Nazis agreeing odious universal norms. Habermas calls it 'discourse ethics'. |
| 7417 | God can't have silly perfections, but how do we decide which ones are 'silly'? [Joslin] |
| Full Idea: It is clear that God cannot have all conceivable perfections, because otherwise he would have absurd perfections (like being the perfect prawn sandwich), so a line must be drawn, and how are we to decide which perfections are appropriate and essential? | |
| From: Jack Joslin (talk [2006]), quoted by PG - Db (ideas) | |
| A reaction: This is an excellent question for curbing the absurdities of those who want to load God with every good thing that can possibly be conceived. Is the God who is also a perfect prawn sandwich more perfect than the one who isn't? |