18 ideas
| 19081 | Coherence with a set of propositions suggests we can know the proposition corresponds [Davidson, by Donnellan] |
| Full Idea: Davidson argues that the coherence of a set of propositions with a set of beliefs is a good indication that the proposition corresponds to objective facts and that we can know that propositions correspond. | |
| From: report of Donald Davidson (Coherence Theory of Truth and Knowledge [1983]) by Keith Donnellan - Putting Humpty Dumpty Together Again §2.2 | |
| A reaction: Young calls this an 'epistemological route to coherentism'. Davidson is sometimes cited as a fan of the coherence theory of truth, but this just seems to accept Russell's point that coherence is a good test for truth. |
| 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. |
| 14797 | Vagueness is a neglected but important part of mathematical thought [Peirce] |
| Full Idea: Logicians have too much neglected the study of vagueness, not suspecting the important part it plays in mathematical thought. It is the antithetical analogue of generality. | |
| From: Charles Sanders Peirce (Critical Common-Sensism [1905], I) |
| 14798 | All communication is vague, and is outside the principle of non-contradiction [Peirce] |
| Full Idea: The 'vague' might be defined as that to which the principle of contradiction does not apply. For it is false neither that an animal (in a vague sense) is male, nor that an animal is female. No communication between persons can be entirely non-vague. | |
| From: Charles Sanders Peirce (Critical Common-Sensism [1905], I) | |
| A reaction: Note that he makes vagueness largely a matter of the way we talk, which is David Lewis's approach, and looks right to me. |
| 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. |
| 8806 | The concepts of belief and truth are linked, since beliefs are meant to fit reality [Davidson] |
| Full Idea: Knowing what a belief is brings with it the concept of objective truth, for the notion of a belief is the notion of a state that may or may not jibe with reality. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.162) | |
| A reaction: I find any discussion of belief that makes no reference to truth (as in Hume) quite puzzling. I can understand it when a belief is just triggered by a sensation ('this is hot'), but not when a belief arrives after careful comparison of reasons. |
| 8252 | Davidson believes experience is non-conceptual, and outside the space of reasons [Davidson, by McDowell] |
| Full Idea: Davidson thinks that experience can be nothing but an extra-conceptual impact on sensibility. So he concludes that experience must be outside the space of reasons. | |
| From: report of Donald Davidson (Coherence Theory of Truth and Knowledge [1983], I.6) by John McDowell - Mind and World I | |
| A reaction: McDowell's challenge to the view that experience is extra-conceptual seems to be the key debate among modern empiricists. My only intuition in this area is that we should beware of all-or-nothing solutions to such problems. |
| 8255 | Davidson says the world influences us causally; I say it influences us rationally [McDowell on Davidson] |
| Full Idea: Davidson urges that we should hold that the world exerts a merely causal influence on our thinking, but I am trying to describe a way in which the world exerts a rational influence on our thinking. | |
| From: comment on Donald Davidson (Coherence Theory of Truth and Knowledge [1983]) by John McDowell - Mind and World II.5 | |
| A reaction: McDowell seems to be fighting for the existence of 'pure' reason in a way that is hard to defend with a thoroughly materialist view of human brains. If the world is coherent, then maybe it is rational, and so has reasons to offer us? |
| 8804 | Reasons for beliefs are not the same as evidence [Davidson] |
| Full Idea: We must find a reason for supposing most of our beliefs are true that is not a form of evidence. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.158) | |
| A reaction: This simple observation strikes me as being a key truth in epistemology. It is the same confusion that creates Jackson's Knowledge Argument (Idea 7377) against physicalism (that experiencing red can be thought to be knowledge). |
| 8802 | Sensations lack the content to be logical; they cause beliefs, but they cannot justify them [Davidson] |
| Full Idea: The relation between a sensation and a belief cannot be logical, since sensations are not beliefs or propositional attitudes. The relation must be causal. Sensations cause some beliefs, but they do not show why the belief is justified. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.157) | |
| A reaction: This is, I am beginning to think, the single most important idea in the whole of modern epistemology. Animals have beliefs caused in this way, and because they only have simple beliefs about immediate things, most of their beliefs are true. |
| 8801 | Coherent justification says only beliefs can be reasons for holding other beliefs [Davidson] |
| Full Idea: What distinguishes a coherence theory of justification is simply the claim that nothing can count as a reason for holding a belief except another belief. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.156) | |
| A reaction: I think I agree fully with this. Red patches and headaches I count as evidence rather than as reasons. Since a red patch can be hallucinatory, and a headache can be dreamed, they can't possibly embody true propositions without critical evaluation. |
| 8805 | Skepticism is false because our utterances agree, because they are caused by the same objects [Davidson] |
| Full Idea: What stands in the way of global skepticism of the senses is the fact that we must take the objects of a belief to be the causes of that belief. And our utterances mean the same thing because belief in their truth is caused by the same objects. | |
| From: Donald Davidson (Coherence Theory of Truth and Knowledge [1983], p.161) | |
| A reaction: This is hardly a knock-down argument against scepticism, but it builds a nice picture. The second half extends the Private Language Argument (e.g. Idea 4158). But I still have non-existent conversations about non-existent things in my dreams. |
| 18703 | Davidson's Cogito: 'I think, therefore I am generally right' [Davidson, by Button] |
| Full Idea: Davidson's Cogito has the form 'I think, therefore I am generally right'. | |
| From: report of Donald Davidson (Coherence Theory of Truth and Knowledge [1983], 16.6) by Tim Button - The Limits of Reason | |
| A reaction: On the whole I would subscribe to this Cogito (as Button calls it), from an evolutionary perspective. There would just be no point in thought if it wasn't generally right in everyday activity. |