120 ideas
16440 | I don't think Lewis's cost-benefit reflective equilibrium approach offers enough guidance [Stalnaker] |
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
16468 | Non-S5 can talk of contingent or necessary necessities [Stalnaker] |
11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
18823 | To say there could have been people who don't exist, but deny those possible things, rejects Barcan [Stalnaker, by Rumfitt] |
11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
11011 | Same say there are positive, negative and neuter free logics [Read] |
16449 | In modal set theory, sets only exist in a possible world if that world contains all of its members [Stalnaker] |
11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
14187 | If logic is topic-neutral that means it delves into all subjects, rather than having a pure subject matter [Read] |
10986 | Not all validity is captured in first-order logic [Read] |
10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
14188 | Not all arguments are valid because of form; validity is just true premises and false conclusion being impossible [Read] |
14182 | If the logic of 'taller of' rests just on meaning, then logic may be the study of merely formal consequence [Read] |
14183 | Maybe arguments are only valid when suppressed premises are all stated - but why? [Read] |
10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
14184 | In modus ponens the 'if-then' premise contributes nothing if the conclusion follows anyway [Read] |
12766 | Logical space is abstracted from the actual world [Stalnaker] |
16464 | We regiment to get semantic structure, for evaluating arguments, and understanding complexities [Stalnaker] |
14186 | Logical connectives contain no information, but just record combination relations between facts [Read] |
16465 | In 'S was F or some other than S was F', the disjuncts need S, but the whole disjunction doesn't [Stalnaker] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
16405 | To understand a name (unlike a description) picking the thing out is sufficient? [Stalnaker] |
11007 | Quantifiers are second-order predicates [Read] |
10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
10988 | Any first-order theory of sets is inadequate [Read] |
10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
16434 | Some say what exists must do so, and nothing else could possible exist [Stalnaker] |
16439 | A nominalist view says existence is having spatio-temporal location [Stalnaker] |
11016 | Would a language without vagueness be usable at all? [Read] |
11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
16443 | Properties are modal, involving possible situations where they are exemplified [Stalnaker] |
16471 | I accept a hierarchy of properties of properties of properties [Stalnaker] |
16452 | Dispositions have modal properties, of which properties things would have counterfactually [Stalnaker] |
14617 | Predicates can't apply to what doesn't exist [Stalnaker] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
12764 | For the bare particular view, properties must be features, not just groups of objects [Stalnaker] |
16407 | Possible worlds allow separating all the properties, without hitting a bare particular [Stalnaker] |
12761 | An essential property is one had in all the possible worlds where a thing exists [Stalnaker] |
16467 | 'Socrates is essentially human' seems to say nothing could be Socrates if it was not human [Stalnaker] |
12763 | Necessarily self-identical, or being what it is, or its world-indexed properties, aren't essential [Stalnaker] |
12762 | Bare particular anti-essentialism makes no sense within modal logic semantics [Stalnaker] |
16453 | The bundle theory makes the identity of indiscernibles a necessity, since the thing is the properties [Stalnaker] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
16466 | Strong necessity is always true; weak necessity is cannot be false [Stalnaker] |
10989 | The standard view of conditionals is that they are truth-functional [Read] |
14286 | In nearby worlds where A is true, 'if A,B' is true or false if B is true or false [Stalnaker] |
11017 | Some people even claim that conditionals do not express propositions [Read] |
10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
10994 | Conditionals are true if minimal revision of the antecedent verifies the consequent [Stalnaker, by Read] |
14185 | Conditionals are just a shorthand for some proof, leaving out the details [Read] |
16438 | Necessity and possibility are fundamental, and there can be no reductive analysis of them [Stalnaker] |
16422 | The necessity of a proposition concerns reality, not our words or concepts [Stalnaker] |
16423 | Conceptual possibilities are metaphysical possibilities we can conceive of [Stalnaker] |
16436 | Modal concepts are central to the actual world, and shouldn't need extravagant metaphysics [Stalnaker] |
16421 | Critics say there are just an a priori necessary part, and an a posteriori contingent part [Stalnaker] |
16429 | A 'centred' world is an ordered triple of world, individual and time [Stalnaker] |
16397 | If it might be true, it might be true in particular ways, and possible worlds describe such ways [Stalnaker] |
16399 | Possible worlds are ontologically neutral, but a commitment to possibilities remains [Stalnaker] |
16398 | Possible worlds allow discussion of modality without controversial modal auxiliaries [Stalnaker] |
10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
16433 | Given actualism, how can there be possible individuals, other than the actual ones? [Stalnaker] |
10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
14285 | A possible world is the ontological analogue of hypothetical beliefs [Stalnaker] |
15793 | We can take 'ways things might have been' as irreducible elements in our ontology [Stalnaker, by Lycan] |
16396 | Kripke's possible worlds are methodological, not metaphysical [Stalnaker] |
16437 | Possible worlds are properties [Stalnaker] |
16444 | Possible worlds don't reduce modality, they regiment it to reveal its structure [Stalnaker] |
16445 | I think of worlds as cells (rather than points) in logical space [Stalnaker] |
10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
12765 | Why imagine that Babe Ruth might be a billiard ball; nothing useful could be said about the ball [Stalnaker] |
16408 | Rigid designation seems to presuppose that differing worlds contain the same individuals [Stalnaker] |
16409 | Unlike Lewis, I defend an actualist version of counterpart theory [Stalnaker] |
16411 | If possible worlds really differ, I can't be in more than one at a time [Stalnaker] |
16412 | If counterparts exist strictly in one world only, this seems to be extreme invariant essentialism [Stalnaker] |
16454 | Modal properties depend on the choice of a counterpart, which is unconstrained by metaphysics [Stalnaker] |
11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
16450 | Anti-haecceitism says there is no more to an individual than meeting some qualitative conditions [Stalnaker] |
19542 | It is nonsense that understanding does not involve knowledge; to understand, you must know [Dougherty/Rysiew] |
19543 | To grasp understanding, we should be more explicit about what needs to be known [Dougherty/Rysiew] |
19541 | Rather than knowledge, our epistemic aim may be mere true belief, or else understanding and wisdom [Dougherty/Rysiew] |
19540 | Don't confuse justified belief with justified believers [Dougherty/Rysiew] |
19539 | If knowledge is unanalysable, that makes justification more important [Dougherty/Rysiew] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
16428 | Meanings aren't in the head, but that is because they are abstract [Stalnaker] |
16474 | How can we know what we are thinking, if content depends on something we don't know? [Stalnaker] |
16406 | If you don't know what you say you can't mean it; what people say usually fits what they mean [Stalnaker] |
16404 | In the use of a name, many individuals are causally involved, but they aren't all the referent [Stalnaker] |
16432 | One view says the causal story is built into the description that is the name's content [Stalnaker] |
16403 | 'Descriptive' semantics gives a system for a language; 'foundational' semantics give underlying facts [Stalnaker] |
16461 | We still lack an agreed semantics for quantifiers in natural language [Stalnaker] |
19538 | Entailment is modelled in formal semantics as set inclusion (where 'mammals' contains 'cats') [Dougherty/Rysiew] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
16401 | To understand an utterance, you must understand what the world would be like if it is true [Stalnaker] |
16410 | Extensional semantics has individuals and sets; modal semantics has intensions, functions of world to extension [Stalnaker] |
16448 | Possible world semantics may not reduce modality, but it can explain it [Stalnaker] |
16430 | Two-D says that a posteriori is primary and contingent, and the necessity is the secondary intension [Stalnaker] |
16431 | In one view, the secondary intension is metasemantic, about how the thinker relates to the content [Stalnaker] |
16442 | I take propositions to be truth conditions [Stalnaker] |
16447 | A theory of propositions at least needs primitive properties of consistency and of truth [Stalnaker] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
14616 | A 'Russellian proposition' is an ordered sequence of individual, properties and relations [Stalnaker] |
16446 | Propositions presumably don't exist if the things they refer to don't exist [Stalnaker] |
18052 | An assertion aims to add to the content of a context [Stalnaker, by Magidor] |
14718 | An assertion is an attempt to rule out certain possibilities, narrowing things down for good planning [Stalnaker, by Schroeter] |