31 ideas
10888 | Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo] |
10889 | The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo] |
10890 | A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo] |
10886 | Determinacy: an object is either in a set, or it isn't [Zalabardo] |
10887 | Specification: Determinate totals of objects always make a set [Zalabardo] |
10897 | A first-order 'sentence' is a formula with no free variables [Zalabardo] |
10893 | Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo] |
10899 | Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo] |
10896 | Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo] |
10898 | The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo] |
10902 | We can do semantics by looking at given propositions, or by building new ones [Zalabardo] |
10892 | We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo] |
10900 | Logically true sentences are true in all structures [Zalabardo] |
10895 | 'Logically true' (|= φ) is true for every truth-assignment [Zalabardo] |
10901 | Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo] |
10894 | A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo] |
10903 | A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo] |
17867 | If a concept is not compact, it will not be presentable to finite minds [Almog] |
17877 | The number series is primitive, not the result of some set theoretic axioms [Almog] |
10891 | If a set is defined by induction, then proof by induction can be applied to it [Zalabardo] |
17872 | Definitionalists rely on snapshot-concepts, instead of on the real processes [Almog] |
17871 | Fregean meanings are analogous to conceptual essence, defining a kind [Almog] |
17866 | Essential definition aims at existence conditions and structural truths [Almog] |
17868 | Surface accounts aren't exhaustive as they always allow unintended twin cases [Almog] |
17870 | Alien 'tigers' can't be tigers if they are not related to our tigers [Almog] |
17869 | Kripke and Putnam offer an intermediary between real and nominal essences [Almog] |
17876 | Individual essences are just cobbled together classificatory predicates [Almog] |
17873 | Water must be related to water, just as tigers must be related to tigers [Almog] |
7517 | I could take a healthy infant and train it up to be any type of specialist I choose [Watson,JB] |
17864 | Defining an essence comes no where near giving a thing's nature [Almog] |
17863 | Essences promise to reveal reality, but actually drive us away from it [Almog] |