11 ideas
| 22642 | Man has an intense natural interest in the consistency of his own thinking [James] |
| Full Idea: After man's interest in breathing freely, the greatest of all his interests (because it never fluctuates or remits….) is his interest in consistency, in feeling that what he now thinks goes with what he thinks on other occasions. | |
| From: William James (The Pragmatist Account of Truth [1908], 'Seventh') | |
| A reaction: People notoriously contradict themselves all the time, but I suspect that it is when they get out of their depth in complexities such as politics. They probably achieve great consistency within their own expertise, and in common knowledge. |
| 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. |
| 22641 | Realities just are, and beliefs are true of them [James] |
| Full Idea: Realities are not true, they are; and beliefs are true of them. | |
| From: William James (The Pragmatist Account of Truth [1908], 'Fourth') | |
| A reaction: At last, a remark by James about truth which I really like. For 'realities' I would use the word 'facts'. |
| 12812 | Things have real essences, but we categorise them according to the ideas we receive [Locke] |
| Full Idea: This I do say, that there are real constitutions in things from whence simple ideas flow, which we observe combin'd in them. But we distinguish particular substances into sorts or genera not by real essences or constitutions, but by observed simple ideas. | |
| From: John Locke (Letters to William Molyneux [1692], 1693.01.20) | |
| A reaction: This is the clearest statement I can find of Locke's position on essences. He is totally committed to their reality, but strongly aware of the empirical constraints which keep us from direct knowledge of them. He would be amazed by modern discoveries. |
| 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. |
| 22640 | We find satisfaction in consistency of all of our beliefs, perceptions and mental connections [James] |
| Full Idea: We find satisfaction in consistency between the present idea and the entire rest of our mental equipment, including the whole order of our sensations, and that of our intuitions of likeness and difference, and our whole stock previously acquired truths. | |
| From: William James (The Pragmatist Account of Truth [1908], 'Fourth') | |
| A reaction: I like this, apart from the idea that the criterion of good coherence seems to be subjective 'satisfaction'. We should ask why some large set of beliefs is coherent. I assume nature is coherent, and truth is the best explanation of our coherence about it. |