69 ideas
| 17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
| 17765 | Propositional language can only relate statements as the same or as different [Walicki] |
| 17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
| 17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
| 17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
| 17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
| 17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
| 17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
| 17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
| 17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
| 17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
| 17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
| 17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
| 17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
| 17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
| 17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
| 17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
| 17754 | Inductive proof depends on the choice of the ordering [Walicki] |
| 15682 | Even fairly simple animals make judgements based on categories [Gelman] |
| 15691 | Children accept real stable categories, with nonobvious potential that gives causal explanations [Gelman] |
| 11897 | A principle of individuation may pinpoint identity and distinctness, now and over time [Mackie,P] |
| 11898 | Individuation may include counterfactual possibilities, as well as identity and persistence [Mackie,P] |
| 11883 | A haecceity is the essential, simple, unanalysable property of being-this-thing [Mackie,P] |
| 15700 | In India, upper-castes essentialize caste more than lower-castes do [Gelman] |
| 15685 | Essentialism is either natural to us, or an accident of our culture, or a necessary result of language [Gelman] |
| 15684 | Children's concepts include nonobvious features, like internal parts, functions and causes [Gelman] |
| 11889 | Essentialism must avoid both reduplication of essences, and multiple occupancy by essences [Mackie,P] |
| 15681 | Essentialism: real or representational? sortal, causal or ideal? real particulars, or placeholders? [Gelman] |
| 11877 | An individual essence is the properties the object could not exist without [Mackie,P] |
| 11882 | No other object can possibly have the same individual essence as some object [Mackie,P] |
| 11886 | There are problems both with individual essences and without them [Mackie,P] |
| 15678 | Essentialism says categories have a true hidden nature which gives an object its identity [Gelman] |
| 15683 | Sortals are needed for determining essence - the thing must be categorised first [Gelman] |
| 15697 | Kind (unlike individual) essentialism assumes preexisting natural categories [Gelman] |
| 11909 | Unlike Hesperus=Phosophorus, water=H2O needs further premisses before it is necessary [Mackie,P] |
| 11899 | Why are any sortals essential, and why are only some of them essential? [Mackie,P] |
| 15687 | Kinship is essence that comes in degrees, and age groups are essences that change over time [Gelman] |
| 11906 | The Kripke and Putnam view of kinds makes them explanatorily basic, but has modal implications [Mackie,P] |
| 15679 | Essentialism comes from the cognitive need to categorise [Gelman] |
| 15698 | We found no evidence that mothers teach essentialism to their children [Gelman] |
| 15709 | Essentialism is useful for predictions, but it is not the actual structure of reality [Gelman] |
| 15696 | Peope favor historical paths over outward properties when determining what something is [Gelman] |
| 11894 | Origin is not a necessity, it is just 'tenacious'; we keep it fixed in counterfactual discussions [Mackie,P] |
| 17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
| 11887 | Transworld identity without individual essences leads to 'bare identities' [Mackie,P] |
| 11890 | De re modality without bare identities or individual essence needs counterparts [Mackie,P] |
| 11892 | Things may only be counterparts under some particular relation [Mackie,P] |
| 11893 | Possibilities for Caesar must be based on some phase of the real Caesar [Mackie,P] |
| 11884 | The theory of 'haecceitism' does not need commitment to individual haecceities [Mackie,P] |
| 15707 | There is intentional, mechanical, teleological, essentialist, vitalist and deontological understanding [Gelman] |
| 15703 | Memories often conform to a theory, rather than being neutral [Gelman] |
| 15708 | Inductive success is rewarded with more induction [Gelman] |
| 15694 | Children overestimate the power of a single example [Gelman] |
| 15695 | Children make errors in induction by focusing too much on categories [Gelman] |
| 15692 | People tend to be satisfied with shallow explanations [Gelman] |
| 11905 | Locke's kind essences are explanatory, without being necessary to the kind [Mackie,P] |
| 15680 | Folk essentialism rests on belief in natural kinds, in hidden properties, and on words indicating structures [Gelman] |
| 15686 | Labels may indicate categories which embody an essence [Gelman] |
| 15690 | Causal properties are seen as more central to category concepts [Gelman] |
| 15688 | Categories are characterized by distance from a prototype [Gelman] |
| 15689 | Theory-based concepts use rich models to show which similarities really matter [Gelman] |
| 15699 | Prelinguistic infants acquire and use many categories [Gelman] |
| 15693 | One sample of gold is enough, but one tree doesn't give the height of trees [Gelman] |
| 15701 | Nouns seem to invoke stable kinds more than predicates do [Gelman] |
| 11907 | Maybe the identity of kinds is necessary, but instances being of that kind is not [Mackie,P] |
| 15702 | Essentialism doesn't mean we know the essences [Gelman] |
| 15705 | Essentialism encourages us to think about the world scientifically [Gelman] |
| 15704 | Essentialism starts from richly structured categories, leading to a search for underlying properties [Gelman] |
| 15706 | A major objection to real essences is the essentialising of social categories like race, caste and occupation [Gelman] |