60 ideas
11832 | We learn a concept's relations by using it, without reducing it to anything [Wiggins] |
18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
18789 | Intuitionist logic looks best as natural deduction [Mares] |
18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
18782 | The connectives are studied either through model theory or through proof theory [Mares] |
11863 | (λx)[Man x] means 'the property x has iff x is a man'. [Wiggins] |
11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
18783 | Many-valued logics lack a natural deduction system [Mares] |
18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
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] |
11869 | Possible worlds rest on the objects about which we have suppositions [Wiggins] |
11850 | Not every story corresponds to a possible world [Wiggins] |
15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
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] |
18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
11860 | Lawlike propensities are enough to individuate natural kinds [Wiggins] |