56 ideas
| 17663 | If you know what it is, investigation is pointless. If you don't, investigation is impossible [Armstrong] |
| 17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
| 17765 | Propositional language can only relate statements as the same or as different [Walicki] |
| 17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
| 17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
| 17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
| 17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
| 17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
| 17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
| 17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
| 17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
| 17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
| 17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
| 17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
| 17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
| 17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
| 17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
| 17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
| 17754 | Inductive proof depends on the choice of the ordering [Walicki] |
| 17688 | Negative facts are supervenient on positive facts, suggesting they are positive facts [Armstrong] |
| 17691 | Nothing is genuinely related to itself [Armstrong] |
| 17679 | All instances of some property are strictly identical [Armstrong] |
| 12677 | Armstrong holds that all basic properties are categorical [Armstrong, by Ellis] |
| 17666 | Actualism means that ontology cannot contain what is merely physically possible [Armstrong] |
| 17667 | Dispositions exist, but their truth-makers are actual or categorical properties [Armstrong] |
| 17687 | If everything is powers there is a vicious regress, as powers are defined by more powers [Armstrong] |
| 17678 | Universals are just the repeatable features of a world [Armstrong] |
| 17669 | Realist regularity theories of laws need universals, to pick out the same phenomena [Armstrong] |
| 17677 | Past, present and future must be equally real if universals are instantiated [Armstrong] |
| 15442 | Universals are abstractions from their particular instances [Armstrong, by Lewis] |
| 17686 | Universals are abstractions from states of affairs [Armstrong] |
| 17668 | It is likely that particulars can be individuated by unique conjunctions of properties [Armstrong] |
| 17680 | The identity of a thing with itself can be ruled out as a pseudo-property [Armstrong] |
| 17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
| 17693 | The necessary/contingent distinction may need to recognise possibilities as real [Armstrong] |
| 17685 | Induction aims at 'all Fs', but abduction aims at hidden or theoretical entities [Armstrong] |
| 17683 | Science suggests that the predicate 'grue' is not a genuine single universal [Armstrong] |
| 17675 | Unlike 'green', the 'grue' predicate involves a time and a change [Armstrong] |
| 17674 | The raven paradox has three disjuncts, confirmed by confirming any one of them [Armstrong] |
| 17672 | A good reason for something (the smoke) is not an explanation of it (the fire) [Armstrong] |
| 17684 | To explain observations by a regular law is to explain the observations by the observations [Armstrong] |
| 17676 | Best explanations explain the most by means of the least [Armstrong] |
| 17664 | Each subject has an appropriate level of abstraction [Armstrong] |
| 7861 | Libet says the processes initiated in the cortex can still be consciously changed [Libet, by Papineau] |
| 6660 | Libet found conscious choice 0.2 secs before movement, well after unconscious 'readiness potential' [Libet, by Lowe] |
| 17692 | We can't deduce the phenomena from the One [Armstrong] |
| 17689 | Absences might be effects, but surely not causes? [Armstrong] |
| 17682 | A universe couldn't consist of mere laws [Armstrong] |
| 17662 | Science depends on laws of nature to study unobserved times and spaces [Armstrong] |
| 17690 | Oaken conditional laws, Iron universal laws, and Steel necessary laws [Armstrong, by PG] |
| 17670 | Newton's First Law refers to bodies not acted upon by a force, but there may be no such body [Armstrong] |
| 8582 | Regularities are lawful if a second-order universal unites two first-order universals [Armstrong, by Lewis] |
| 17671 | A naive regularity view says if it never occurs then it is impossible [Armstrong] |
| 17681 | The laws of nature link properties with properties [Armstrong] |
| 16246 | Rather than take necessitation between universals as primitive, just make laws primitive [Maudlin on Armstrong] |
| 9480 | Armstrong has an unclear notion of contingent necessitation, which can't necessitate anything [Bird on Armstrong] |