43 ideas
| 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] |
| 10405 | In the iterative conception of sets, they form a natural hierarchy [Swoyer] |
| 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] |
| 10407 | Logical Form explains differing logical behaviour of similar sentences [Swoyer] |
| 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] |
| 14592 | Some abstract things have a beginning and end, so may exist in time (though not space) [Swoyer] |
| 10421 | Supervenience is nowadays seen as between properties, rather than linguistic [Swoyer] |
| 14594 | Ontologists seek existence and identity conditions, and modal and epistemic status for a thing [Swoyer] |
| 10410 | Anti-realists can't explain different methods to measure distance [Swoyer] |
| 10399 | If a property such as self-identity can only be in one thing, it can't be a universal [Swoyer] |
| 10416 | Can properties have parts? [Swoyer] |
| 14595 | Can properties exemplify other properties? [Swoyer] |
| 10417 | There are only first-order properties ('red'), and none of higher-order ('coloured') [Swoyer] |
| 10413 | The best-known candidate for an identity condition for properties is necessary coextensiveness [Swoyer] |
| 10402 | Various attempts are made to evade universals being wholly present in different places [Swoyer] |
| 10400 | Conceptualism says words like 'honesty' refer to concepts, not to properties [Swoyer] |
| 10403 | If properties are abstract objects, then their being abstract exemplifies being abstract [Swoyer] |
| 14593 | Quantum field theory suggests that there are, fundamentally, no individual things [Swoyer] |
| 17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
| 10406 | One might hope to reduce possible worlds to properties [Swoyer] |
| 10404 | Extreme empiricists can hardly explain anything [Swoyer] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 10408 | Intensions are functions which map possible worlds to sets of things denoted by an expression [Swoyer] |
| 10409 | Research suggests that concepts rely on typical examples [Swoyer] |
| 10401 | The F and G of logic cover a huge range of natural language combinations [Swoyer] |
| 10420 | Maybe a proposition is just a property with all its places filled [Swoyer] |
| 10412 | If laws are mere regularities, they give no grounds for future prediction [Swoyer] |
| 10411 | Two properties can have one power, and one property can have two powers [Swoyer] |