13 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. |
| 11993 | Jones may cease to exist without some simple property, but that doesn't make it essential [Kung] |
| Full Idea: If Jones ceases to be a father, or ceases to be over eight years old, he will cease to exist, yet these properties surely do not belong essentially to him. | |
| From: Joan Kung (Aristotle on Essence and Explanation [1977], II) | |
| A reaction: This seems to correct, though I would doubt whether either of these count as true properties, in the causal sense I prefer. If being 'over 8' is a property, how many 'over n' or 'under m' properties does he have? One for each quantum moment? |
| 11997 | A property may belong essentially to one thing and contingently to another [Kung] |
| Full Idea: It is possible that a property may belong essentially to one thing and contingently to another. | |
| From: Joan Kung (Aristotle on Essence and Explanation [1977], III) | |
| A reaction: Thus a love of blues music may be part of your essence, but only a minor part of me. Sounds right. Spin or charge are part of the essence of an electron, but only contingently part of a child's top. |
| 11992 | Aristotelian essences underlie a thing's existence, explain it, and must belong to it [Kung] |
| Full Idea: Three essentialist claims are labelled 'Aristotelian': the thing would cease to exist without the property; an essential property is explanatory; and it is such that it must belong to everything to which it belongs. | |
| From: Joan Kung (Aristotle on Essence and Explanation [1977], Intro) | |
| A reaction: She says the second one is indispensable, and that it rules out the third one. My working assumption, like hers, is that the second one is the key part of the game, because Aristotle wanted to explain things. |
| 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. |
| 8800 | If you would deny a truth if you know the full evidence, then knowledge has social aspects [Harman, by Sosa] |
| Full Idea: If one reads of a genuine assassination, but then fails to read the reports next day which untruthfully deny the event, one probably does not know of the event. But we must conclude that knowledge has a further 'social aspect'. | |
| From: report of Gilbert Harman (Induction [1970], §IV) by Ernest Sosa - The Raft and the Pyramid Appx | |
| A reaction: I doubt if this is enough to support an externalist account of defeasibility. Wise people don't 'know' of an event after one report. For 24 hours the Royalists thought they had won Marston Moor! You know he's dead when you see the Zapruder film. |
| 11996 | Some non-essential properties may explain more than essential-but-peripheral ones do [Kung] |
| Full Idea: It seems highly likely that some non-essential properties may explain more about the individual or about things of his kind than the peripheral properties. | |
| From: Joan Kung (Aristotle on Essence and Explanation [1977], II) | |
| A reaction: Another important issue, if one is defending the explanatory role of essences. It is not only essences which explain. A key question is whether we endorse individual essences as well as generic ones. I think we should. They explain the details. |
| 11995 | Some peripheral properties are explained by essential ones, but don't themselves explain properties [Kung] |
| Full Idea: There will be demonstrated properties at the edge of the system, so to speak. They will be explained in terms of the essential properties of the basic entities and principles of the science, but will themselves not be explanatory of further properties. | |
| From: Joan Kung (Aristotle on Essence and Explanation [1977], II) | |
| A reaction: This is an important line of thought which needs clarification. We can't glibly say that essences are what explain the other properties. Some properties do more than others to explain subsequent dependent properties. |