23 ideas
9065 | S5 collapses iterated modalities (◊□P→□P, and ◊◊P→◊P) [Keefe/Smith] |
13831 | Logic is based on transitions between sentences [Prawitz] |
13827 | Logical consequence isn't a black box (Tarski's approach); we should explain how arguments work [Prawitz] |
13825 | Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz] |
13823 | In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz] |
13826 | Model theory looks at valid sentences and consequence, but not how we know these things [Prawitz] |
9064 | Objects such as a cloud or Mount Everest seem to have fuzzy boundaries in nature [Keefe/Smith] |
9044 | If someone is borderline tall, no further information is likely to resolve the question [Keefe/Smith] |
9048 | The simplest approach, that vagueness is just ignorance, retains classical logic and semantics [Keefe/Smith] |
9055 | The epistemic view of vagueness must explain why we don't know the predicate boundary [Keefe/Smith] |
9049 | Supervaluationism keeps true-or-false where precision can be produced, but not otherwise [Keefe/Smith] |
9056 | Vague statements lack truth value if attempts to make them precise fail [Keefe/Smith] |
9058 | Some of the principles of classical logic still fail with supervaluationism [Keefe/Smith] |
9059 | The semantics of supervaluation (e.g. disjunction and quantification) is not classical [Keefe/Smith] |
9060 | Supervaluation misunderstands vagueness, treating it as a failure to make things precise [Keefe/Smith] |
9050 | A third truth-value at borderlines might be 'indeterminate', or a value somewhere between 0 and 1 [Keefe/Smith] |
9061 | People can't be placed in a precise order according to how 'nice' they are [Keefe/Smith] |
9062 | If truth-values for vagueness range from 0 to 1, there must be someone who is 'completely tall' [Keefe/Smith] |
9063 | How do we decide if my coat is red to degree 0.322 or 0.321? [Keefe/Smith] |
9045 | Vague predicates involve uncertain properties, uncertain objects, and paradoxes of gradual change [Keefe/Smith] |
9047 | Many vague predicates are multi-dimensional; 'big' involves height and volume; heaps include arrangement [Keefe/Smith] |
9053 | If there is a precise borderline area, that is not a case of vagueness [Keefe/Smith] |
3016 | Even the gods cannot strive against necessity [Pittacus, by Diog. Laertius] |