55 ideas
| 11832 | We learn a concept's relations by using it, without reducing it to anything [Wiggins] |
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| 11863 | (λx)[Man x] means 'the property x has iff x is a man'. [Wiggins] |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| 14746 | What exists can't depend on our conceptual scheme, and using all conceptual schemes is too liberal [Sider on Wiggins] |
| 11900 | We can accept criteria of distinctness and persistence, without making the counterfactual claims [Mackie,P on Wiggins] |
| 11870 | Activity individuates natural things, functions do artefacts, and intentions do artworks [Wiggins] |
| 11866 | The idea of 'thisness' is better expressed with designation/predication and particular/universal [Wiggins] |
| 11896 | A sortal essence is a thing's principle of individuation [Wiggins, by Mackie,P] |
| 15835 | Wiggins's sortal essentialism rests on a thing's principle of individuation [Wiggins, by Mackie,P] |
| 11841 | The evening star is the same planet but not the same star as the morning star, since it is not a star [Wiggins] |
| 10679 | 'Sortalism' says parts only compose a whole if it falls under a sort or kind [Wiggins, by Hossack] |
| 14363 | Identity a=b is only possible with some concept to give persistence and existence conditions [Wiggins, by Strawson,P] |
| 14364 | A thing is necessarily its highest sortal kind, which entails an essential constitution [Wiggins, by Strawson,P] |
| 11851 | Many predicates are purely generic, or pure determiners, rather than sortals [Wiggins] |
| 11865 | The possibility of a property needs an essential sortal concept to conceive it [Wiggins] |
| 14744 | Objects can only coincide if they are of different kinds; trees can't coincide with other trees [Wiggins, by Sider] |
| 11852 | Is the Pope's crown one crown, if it is made of many crowns? [Wiggins] |
| 11875 | Boundaries are not crucial to mountains, so they are determinate without a determinate extent [Wiggins] |
| 14749 | Identity is an atemporal relation, but composition is relative to times [Wiggins, by Sider] |
| 11844 | If I destroy an item, I do not destroy each part of it [Wiggins] |
| 11861 | We can forget about individual or particularized essences [Wiggins] |
| 11871 | Essences are not explanations, but individuations [Wiggins] |
| 11879 | Essentialism is best represented as a predicate-modifier: □(a exists → a is F) [Wiggins, by Mackie,P] |
| 11835 | The nominal essence is the idea behind a name used for sorting [Wiggins] |
| 11876 | It is easier to go from horses to horse-stages than from horse-stages to horses [Wiggins] |
| 11858 | The question is not what gets the title 'Theseus' Ship', but what is identical with the original [Wiggins] |
| 11843 | Identity over a time and at a time aren't different concepts [Wiggins] |
| 11864 | Hesperus=Hesperus, and Phosphorus=Hesperus, so necessarily Phosphorus=Hesperus [Wiggins] |
| 11831 | The formal properties of identity are reflexivity and Leibniz's Law [Wiggins] |
| 14362 | Relative Identity is incompatible with the Indiscernibility of Identicals [Wiggins, by Strawson,P] |
| 11838 | Relativity of Identity makes identity entirely depend on a category [Wiggins] |
| 11847 | To identify two items, we must have a common sort for them [Wiggins] |
| 11839 | Do both 'same f as' and '=' support Leibniz's Law? [Wiggins] |
| 11845 | Substitutivity, and hence most reasoning, needs Leibniz's Law [Wiggins] |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| 11869 | Possible worlds rest on the objects about which we have suppositions [Wiggins] |
| 11850 | Not every story corresponds to a possible world [Wiggins] |
| 11848 | Asking 'what is it?' nicely points us to the persistence of a continuing entity [Wiggins] |
| 11859 | The mind conceptualizes objects; yet objects impinge upon the mind [Wiggins] |
| 11836 | We can use 'concept' for the reference, and 'conception' for sense [Wiggins] |
| 3031 | The greatest good is not the achievement of desire, but to desire what is proper [Menedemus, by Diog. Laertius] |
| 11860 | Lawlike propensities are enough to individuate natural kinds [Wiggins] |