78 ideas
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
9449 | The plausible Barcan formula implies modality in the actual world [Bird] |
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] |
11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [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] |
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] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
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] |
9501 | If all existents are causally active, that excludes abstracta and causally isolated objects [Bird] |
9500 | If naturalism refers to supervenience, that leaves necessary entities untouched [Bird] |
11016 | Would a language without vagueness be usable at all? [Read] |
11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
9502 | There might be just one fundamental natural property [Bird] |
9477 | Categorical properties are not modally fixed, but change across possible worlds [Bird] |
9490 | The categoricalist idea is that a property is only individuated by being itself [Bird] |
9495 | If we abstractly define a property, that doesn't mean some object could possess it [Bird] |
9492 | Categoricalists take properties to be quiddities, with no essential difference between them [Bird] |
9503 | To name an abundant property is either a Fregean concept, or a simple predicate [Bird] |
14540 | Only real powers are fundamental [Bird, by Mumford/Anjum] |
9450 | If all properties are potencies, and stimuli and manifestation characterise them, there is a regress [Bird] |
9498 | The essence of a potency involves relations, e.g. mass, to impressed force and acceleration [Bird] |
9474 | A disposition is finkish if a time delay might mean the manifestation fizzles out [Bird] |
9475 | A robust pot attached to a sensitive bomb is not fragile, but if struck it will easily break [Bird] |
9499 | Megarian actualists deny unmanifested dispositions [Bird] |
9486 | Why should a universal's existence depend on instantiation in an existing particular? [Bird] |
9472 | Resemblance itself needs explanation, presumably in terms of something held in common [Bird] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
9482 | If the laws necessarily imply p, that doesn't give a new 'nomological' necessity [Bird] |
9481 | Logical necessitation is not a kind of necessity; George Orwell not being Eric Blair is not a real possibility [Bird] |
10989 | The standard view of conditionals is that they are truth-functional [Read] |
10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
11017 | Some people even claim that conditionals do not express propositions [Read] |
9505 | Empiricist saw imaginability and possibility as close, but now they seem remote [Bird] |
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] |
10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
9491 | Haecceitism says identity is independent of qualities and without essence [Bird] |
9487 | We can't reject all explanations because of a regress; inexplicable A can still explain B [Bird] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
9493 | We should explain causation by powers, not powers by causation [Bird] |
9494 | Singularism about causes is wrong, as the universals involved imply laws [Bird] |
9507 | Laws are explanatory relationships of things, which supervene on their essences [Bird] |
9488 | Laws are either disposition regularities, or relations between properties [Bird] |
9496 | That other diamonds are hard does not explain why this one is [Bird] |
9479 | Dispositional essentialism says laws (and laws about laws) are guaranteed regularities [Bird] |
9473 | Laws cannot offer unified explanations if they don't involve universals [Bird] |
9484 | If the universals for laws must be instantiated, a vanishing particular could destroy a law [Bird] |
9506 | Salt necessarily dissolves in water, because of the law which makes the existence of salt possible [Bird] |
23713 | Most laws supervene on fundamental laws, which are explained by basic powers [Bird, by Friend/Kimpton-Nye] |
9489 | Essentialism can't use conditionals to explain regularities, because of possible interventions [Bird] |
9504 | The relational view of space-time doesn't cover times and places where things could be [Bird] |
20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |