61 ideas
| 18395 | Sets are mereological sums of the singletons of their members [Lewis, by Armstrong] |
| 15496 | We can build set theory on singletons: classes are then fusions of subclasses, membership is the singleton [Lewis] |
| 15500 | Classes divide into subclasses in many ways, but into members in only one way [Lewis] |
| 15499 | A subclass of a subclass is itself a subclass; a member of a member is not in general a member [Lewis] |
| 15503 | We needn't accept this speck of nothingness, this black hole in the fabric of Reality! [Lewis] |
| 15498 | We can accept the null set, but there is no null class of anything [Lewis] |
| 15502 | There are four main reasons for asserting that there is an empty set [Lewis] |
| 15497 | We can replace the membership relation with the member-singleton relation (plus mereology) [Lewis] |
| 15506 | If we don't understand the singleton, then we don't understand classes [Lewis] |
| 15511 | If singleton membership is external, why is an object a member of one rather than another? [Lewis] |
| 15513 | Maybe singletons have a structure, of a thing and a lasso? [Lewis] |
| 15507 | Set theory has some unofficial axioms, generalisations about how to understand it [Lewis] |
| 10191 | Set theory reduces to a mereological theory with singletons as the only atoms [Lewis, by MacBride] |
| 15523 | Set theory isn't innocent; it generates infinities from a single thing; but mathematics needs it [Lewis] |
| 15508 | If singletons are where their members are, then so are all sets [Lewis] |
| 15514 | A huge part of Reality is only accepted as existing if you have accepted set theory [Lewis] |
| 15525 | Plural quantification lacks a complete axiom system [Lewis] |
| 15518 | I like plural quantification, but am not convinced of its connection with second-order logic [Lewis] |
| 15524 | Zermelo's model of arithmetic is distinctive because it rests on a primitive of set theory [Lewis] |
| 15517 | Giving up classes means giving up successful mathematics because of dubious philosophy [Lewis] |
| 15515 | To be a structuralist, you quantify over relations [Lewis] |
| 15520 | Existence doesn't come in degrees; once asserted, it can't then be qualified [Lewis] |
| 15501 | We have no idea of a third sort of thing, that isn't an individual, a class, or their mixture [Lewis] |
| 15504 | Atomless gunk is an individual whose parts all have further proper parts [Lewis] |
| 15516 | A property is any class of possibilia [Lewis] |
| 14748 | The many are many and the one is one, so they can't be identical [Lewis] |
| 6129 | Lewis affirms 'composition as identity' - that an object is no more than its parts [Lewis, by Merricks] |
| 15512 | In mereology no two things consist of the same atoms [Lewis] |
| 15519 | Trout-turkeys exist, despite lacking cohesion, natural joints and united causal power [Lewis] |
| 15521 | Given cats, a fusion of cats adds nothing further to reality [Lewis] |
| 15522 | The one has different truths from the many; it is one rather than many, one rather than six [Lewis] |
| 10566 | Lewis prefers giving up singletons to giving up sums [Lewis, by Fine,K] |
| 14244 | Lewis only uses fusions to create unities, but fusions notoriously flatten our distinctions [Oliver/Smiley on Lewis] |
| 10660 | A commitment to cat-fusions is not a further commitment; it is them and they are it [Lewis] |
| 15509 | Some say qualities are parts of things - as repeatable universals, or as particulars [Lewis] |
| 17979 | Research shows perceptual discrimination is sharper at category boundaries [Murphy] |
| 18690 | Induction is said to just compare properties of categories, but the type of property also matters [Murphy] |
| 17980 | The main theories of concepts are exemplar, prototype and knowledge [Murphy] |
| 17969 | The classical definitional approach cannot distinguish typical and atypical category members [Murphy] |
| 17970 | Classical concepts follow classical logic, but concepts in real life don't work that way [Murphy] |
| 17971 | Classical concepts are transitive hierarchies, but actual categories may be intransitive [Murphy] |
| 17972 | The classical core is meant to be the real concept, but actually seems unimportant [Murphy] |
| 17973 | The theoretical and practical definitions for the classical view are very hard to find [Murphy] |
| 17975 | There is no 'ideal' bird or dog, and prototypes give no information about variability [Murphy] |
| 17976 | Prototypes are unified representations of the entire category (rather than of members) [Murphy] |
| 18691 | The prototype theory uses observed features, but can't include their construction [Murphy] |
| 17983 | The prototype theory handles hierarchical categories and combinations of concepts well [Murphy] |
| 17985 | Prototypes theory of concepts is best, as a full description with weighted typical features [Murphy] |
| 17986 | Learning concepts is forming prototypes with a knowledge structure [Murphy] |
| 17977 | The exemplar view of concepts says 'dogs' is the set of dogs I remember [Murphy] |
| 17981 | Children using knowing and essentialist categories doesn't fit the exemplar view [Murphy] |
| 17982 | Exemplar theory struggles with hierarchical classification and with induction [Murphy] |
| 17984 | Conceptual combination must be compositional, and can't be built up from exemplars [Murphy] |
| 17987 | The concept of birds from exemplars must also be used in inductions about birds [Murphy] |
| 17974 | The most popular theories of concepts are based on prototypes or exemplars [Murphy] |
| 17978 | We do not learn concepts in isolation, but as an integrated part of broader knowledge [Murphy] |
| 18687 | Concepts with familiar contents are easier to learn [Murphy] |
| 18688 | Some knowledge is involved in instant use of categories, other knowledge in explanations [Murphy] |
| 18689 | People categorise things consistent with their knowledge, even rejecting some good evidence [Murphy] |
| 1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
| 5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |