16 ideas
3745 | Must sentences make statements to qualify for truth? [O'Connor] |
Full Idea: Maybe a sentence is not a candidate for truth until it is used to make a statement. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
3742 | Beliefs must match facts, but also words must match beliefs [O'Connor] |
Full Idea: Our beliefs must claim a correspondence with facts, and then the verbal expression of the belief must correspond to the belief itself. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.4) |
3744 | The semantic theory requires sentences as truth-bearers, not propositions [O'Connor] |
Full Idea: The Semantic Theory of truth requires that sentences are truth-bearers (rather than statements, or propositions). | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
3749 | What does 'true in English' mean? [O'Connor] |
Full Idea: We do not seem to have any use in ordinary discourse for phrases like 'true in English', 'false in German'. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], II.1) |
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) |
3746 | Logic seems to work for unasserted sentences [O'Connor] |
Full Idea: If sentences can have truth-values only when they occur as asserted, it would be impossible to have a truth-functional basis to logic. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.6) |
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. |
3747 | Events are fast changes which are of interest to us [O'Connor] |
Full Idea: The standard cases of events are physical changes which happen sufficiently fast to be observed as changes, and which are of sufficient interest to us to be noticed or commented on. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.7) |
12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |
Full Idea: A whole must possess an attribute peculiar to and characteristic of it as a whole; there must be a characteristic relation of dependence between the parts; and the whole must have some structure which gives it characteristics. | |
From: Rescher,N/Oppenheim,P (Logical Analysis of Gestalt Concepts [1955], p.90), quoted by Peter Simons - Parts 9.2 | |
A reaction: Simons says these are basically sensible conditions, and tries to fill them out. They seem a pretty good start, and I must resist the temptation to rush to borderline cases. |
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. |
3743 | We can't contemplate our beliefs until we have expressed them [O'Connor] |
Full Idea: It is only when beliefs are given some symbolic expression that they acquire the precision and stability that enables us to entertain them. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.5) |
3748 | Without language our beliefs are particular and present [O'Connor] |
Full Idea: Without language we would be restricted to particular beliefs about the here and now. | |
From: D.J. O'Connor (The Correspondence Theory of Truth [1975], Ch.8) |