67 ideas
| 11832 | We learn a concept's relations by using it, without reducing it to anything [Wiggins] |
| 9672 | Free logic is one of the few first-order non-classical logics [Priest,G] |
| 9697 | X1 x X2 x X3... x Xn indicates the 'cartesian product' of those sets [Priest,G] |
| 9685 | <a,b&62; is a set whose members occur in the order shown [Priest,G] |
| 9675 | a ∈ X says a is an object in set X; a ∉ X says a is not in X [Priest,G] |
| 9674 | {x; A(x)} is a set of objects satisfying the condition A(x) [Priest,G] |
| 9673 | {a1, a2, ...an} indicates that a set comprising just those objects [Priest,G] |
| 9677 | Φ indicates the empty set, which has no members [Priest,G] |
| 9676 | {a} is the 'singleton' set of a (not the object a itself) [Priest,G] |
| 9679 | X⊂Y means set X is a 'proper subset' of set Y [Priest,G] |
| 9678 | X⊆Y means set X is a 'subset' of set Y [Priest,G] |
| 9681 | X = Y means the set X equals the set Y [Priest,G] |
| 9683 | X ∩ Y indicates the 'intersection' of sets X and Y, the objects which are in both sets [Priest,G] |
| 9682 | X∪Y indicates the 'union' of all the things in sets X and Y [Priest,G] |
| 9684 | Y - X is the 'relative complement' of X with respect to Y; the things in Y that are not in X [Priest,G] |
| 9694 | The 'relative complement' is things in the second set not in the first [Priest,G] |
| 9693 | The 'intersection' of two sets is a set of the things that are in both sets [Priest,G] |
| 9692 | The 'union' of two sets is a set containing all the things in either of the sets [Priest,G] |
| 9698 | The 'induction clause' says complex formulas retain the properties of their basic formulas [Priest,G] |
| 9688 | A 'singleton' is a set with only one member [Priest,G] |
| 9687 | A 'member' of a set is one of the objects in the set [Priest,G] |
| 9695 | An 'ordered pair' (or ordered n-tuple) is a set with its members in a particular order [Priest,G] |
| 9696 | A 'cartesian product' of sets is the set of all the n-tuples with one member in each of the sets [Priest,G] |
| 9686 | A 'set' is a collection of objects [Priest,G] |
| 9689 | The 'empty set' or 'null set' has no members [Priest,G] |
| 9690 | A set is a 'subset' of another set if all of its members are in that set [Priest,G] |
| 9691 | A 'proper subset' is smaller than the containing set [Priest,G] |
| 9680 | The empty set Φ is a subset of every set (including itself) [Priest,G] |
| 11863 | (λx)[Man x] means 'the property x has iff x is a man'. [Wiggins] |
| 10801 | Either reference really matters, or we don't need to replace it with substitutions [Quine] |
| 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] |
| 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] |
| 11860 | Lawlike propensities are enough to individuate natural kinds [Wiggins] |