29 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] |
10895 | 'Logically true' (|= φ) is true for every truth-assignment [Zalabardo] |
10900 | Logically true sentences are true in all structures [Zalabardo] |
10894 | A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo] |
10901 | Some formulas are 'satisfiable' if there is a structure and interpretation that makes them 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] |
10891 | If a set is defined by induction, then proof by induction can be applied to it [Zalabardo] |
19682 | Internalists are much more interested in evidence than externalists are [McGrew] |
19684 | Does spotting a new possibility count as evidence? [McGrew] |
19687 | Absence of evidence proves nothing, and weird claims need special evidence [McGrew] |
19688 | Every event is highly unlikely (in detail), but may be perfectly plausible [McGrew] |
19686 | Criminal law needs two separate witnesses, but historians will accept one witness [McGrew] |
19680 | Maybe all evidence consists of beliefs, rather than of facts [McGrew] |
19681 | If all evidence is propositional, what is the evidence for the proposition? Do we face a regress? [McGrew] |
19689 | Several unreliable witnesses can give good support, if they all say the same thing [McGrew] |
19683 | Narrow evidentialism relies wholly on propositions; the wider form includes other items [McGrew] |
19685 | Falsificationism would be naive if even a slight discrepancy in evidence killed a theory [McGrew] |
1513 | The Egyptians were the first to say the soul is immortal and reincarnated [Herodotus] |