32 ideas
10143 | 'Creative definitions' do not presuppose the existence of the objects defined [Fine,K] |
9143 | Implicit definitions must be satisfiable, creative definitions introduce things, contextual definitions build on things [Fine,K, by Cook/Ebert] |
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] |
10145 | Abstracts cannot be identified with sets [Fine,K] |
10136 | Points in Euclidean space are abstract objects, but not introduced by abstraction [Fine,K] |
10144 | Postulationism says avoid abstract objects by giving procedures that produce truth [Fine,K] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
8836 | Must all justification be inferential? [Ginet] |
8837 | Inference cannot originate justification, it can only transfer it from premises to conclusion [Ginet] |
9144 | Fine's 'procedural postulationism' uses creative definitions, but avoids abstract ontology [Fine,K, by Cook/Ebert] |
10141 | Many different kinds of mathematical objects can be regarded as forms of abstraction [Fine,K] |
10135 | We can abstract from concepts (e.g. to number) and from objects (e.g. to direction) [Fine,K] |
9142 | Fine considers abstraction as reconceptualization, to produce new senses by analysing given senses [Fine,K, by Cook/Ebert] |
10137 | Abstractionism can be regarded as an alternative to set theory [Fine,K] |
10138 | An object is the abstract of a concept with respect to a relation on concepts [Fine,K] |