11 ideas
| 16030 | 'Nominal' definitions identify things, but fail to give their essence [Jones,J-E] |
| Full Idea: In the Aristotelian tradition, a 'nominal' definition is a pseudo-definition that identifies the members of the species or genus, but fails to capture the essence, e.g. 'man is the featherless biped'. | |
| From: Jan-Erik Jones (Real Essence [2012], §2) | |
| A reaction: You can 'individuate' an object as 'the only object in that drawer', while revealing nothing about it. So what must a definition do, in addition to picking something out uniquely? |
| 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. |
| 22449 | When we say 'is red' we don't mean 'seems red to most people' [Foot] |
| Full Idea: One might think that 'is red' means the same as 'seems red to most people', forgetting that when asked if an object is red we look at it to see if it is red, and not in order to estimate the reaction that others will have to it. | |
| From: Philippa Foot (Moral Relativism [1979], p.23) | |
| A reaction: True, but we are conscious of our own reliability as observers (e.g. if colourblind, or with poor hearing or eyesight). I don't take my glasses off, have a look, and pronounce that the object is blurred. Ordinary language philosophy in action. |
| 22451 | All people need affection, cooperation, community and help in trouble [Foot] |
| Full Idea: There is a great deal that all men have in common; all need affection, the cooperation of others, a place in a community, and help in trouble. | |
| From: Philippa Foot (Moral Relativism [1979], p.33) | |
| A reaction: There seem to be some people who don't need affection or a place in a community, though it is hard to imagine them being happy. These kind of facts are the basis for any sensible cognitivist view of ethics. They are basic to Foot's view. |
| 22452 | Do we have a concept of value, other than wanting something, or making an effort to get it? [Foot] |
| Full Idea: Do we know what we mean by saying that anything has value, or even that we value it, as opposed to wanting it or being prepared to go to trouble to get it? | |
| From: Philippa Foot (Moral Relativism [1979], p.35) | |
| A reaction: Well, I value Rembrandt paintings, but have no aspiration to own one (and would refuse it if offered, because I couldn't look after it properly). And 'we' don't want to move the Taj Mahal to London. She has not expressed this good point very well. |