37 ideas
3123 | Science is in the business of carving nature at the joints [Segal] |
3125 | Psychology studies the way rationality links desires and beliefs to causality [Segal] |
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] |
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] |
10891 | If a set is defined by induction, then proof by induction can be applied to it [Zalabardo] |
3105 | Is 'Hesperus = Phosphorus' metaphysically necessary, but not logically or epistemologically necessary? [Segal] |
3106 | If claims of metaphysical necessity are based on conceivability, we should be cautious [Segal] |
3113 | The success and virtue of an explanation do not guarantee its truth [Segal] |
3112 | Folk psychology is ridiculously dualist in its assumptions [Segal] |
3110 | Humans are made of H2O, so 'twins' aren't actually feasible [Segal] |
3124 | Externalists can't assume old words refer to modern natural kinds [Segal] |
3108 | If 'water' has narrow content, it refers to both H2O and XYZ [Segal] |
3109 | If content is external, so are beliefs and desires [Segal] |
3117 | Concepts can survive a big change in extension [Segal] |
3116 | Maybe experts fix content, not ordinary users [Segal] |
3104 | Must we relate to some diamonds to understand them? [Segal] |
3111 | Externalism can't explain concepts that have no reference [Segal] |
3103 | Maybe content involves relations to a language community [Segal] |
3121 | If content is narrow, my perfect twin shares my concepts [Segal] |
3118 | If thoughts ARE causal, we can't explain how they cause things [Segal] |
3119 | Even 'mass' cannot be defined in causal terms [Segal] |
6005 | Animals are dangerous and nourishing, and can't form contracts of justice [Hermarchus, by Sedley] |