84 ideas
| 13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
| 5278 | Philosophy is no more than abstractions concerning observations of human historical development [Marx/Engels] |
| 13477 | The problems are the monuments of philosophy [Hart,WD] |
| 13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
| 13469 | Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD] |
| 13504 | Truth for sentences is satisfaction of formulae; for sentences, either all sequences satisfy it (true) or none do [Hart,WD] |
| 13503 | A first-order language has an infinity of T-sentences, which cannot add up to a definition of truth [Hart,WD] |
| 13500 | Conditional Proof: infer a conditional, if the consequent can be deduced from the antecedent [Hart,WD] |
| 13502 | ∃y... is read as 'There exists an individual, call it y, such that...', and not 'There exists a y such that...' [Hart,WD] |
| 13456 | Set theory articulates the concept of order (through relations) [Hart,WD] |
| 13497 | Nowadays ZFC and NBG are the set theories; types are dead, and NF is only useful for the whole universe [Hart,WD] |
| 13443 | ∈ relates across layers, while ⊆ relates within layers [Hart,WD] |
| 13442 | Without the empty set we could not form a∩b without checking that a and b meet [Hart,WD] |
| 13493 | In the modern view, foundation is the heart of the way to do set theory [Hart,WD] |
| 13495 | Foundation Axiom: an nonempty set has a member disjoint from it [Hart,WD] |
| 13462 | With the Axiom of Choice every set can be well-ordered [Hart,WD] |
| 13461 | We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD] |
| 13516 | If we accept that V=L, it seems to settle all the open questions of set theory [Hart,WD] |
| 13441 | Naïve set theory has trouble with comprehension, the claim that every predicate has an extension [Hart,WD] |
| 13494 | The iterative conception may not be necessary, and may have fixed points or infinitely descending chains [Hart,WD] |
| 13460 | 'Well-ordering' must have a least member, so it does the natural numbers but not the integers [Hart,WD] |
| 13458 | A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD] |
| 13457 | A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [Hart,WD] |
| 13490 | Von Neumann defines α<β as α∈β [Hart,WD] |
| 13481 | Maybe sets should be rethought in terms of the even more basic categories [Hart,WD] |
| 13506 | The universal quantifier can't really mean 'all', because there is no universal set [Hart,WD] |
| 13513 | Models are ways the world might be from a first-order point of view [Hart,WD] |
| 13505 | Model theory studies how set theory can model sets of sentences [Hart,WD] |
| 13511 | Model theory is mostly confined to first-order theories [Hart,WD] |
| 13512 | Modern model theory begins with the proof of Los's Conjecture in 1962 [Hart,WD] |
| 13496 | First-order logic is 'compact': consequences of a set are consequences of a finite subset [Hart,WD] |
| 13484 | Berry's Paradox: we succeed in referring to a number, with a term which says we can't do that [Hart,WD] |
| 13482 | The Burali-Forti paradox is a crisis for Cantor's ordinals [Hart,WD] |
| 13507 | The machinery used to solve the Liar can be rejigged to produce a new Liar [Hart,WD] |
| 9117 | The smallest heap has four objects: three on the bottom, one on the top [Hart,WD, by Sorensen] |
| 13459 | The less-than relation < well-orders, and partially orders, and totally orders the ordinal numbers [Hart,WD] |
| 13463 | There are at least as many infinite cardinals as transfinite ordinals (because they will map) [Hart,WD] |
| 13491 | The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD] |
| 13492 | Von Neumann's ordinals generalise into the transfinite better, because Zermelo's ω is a singleton [Hart,WD] |
| 13446 | 19th century arithmetization of analysis isolated the real numbers from geometry [Hart,WD] |
| 13509 | We can establish truths about infinite numbers by means of induction [Hart,WD] |
| 13474 | Euclid has a unique parallel, spherical geometry has none, and saddle geometry has several [Hart,WD] |
| 13471 | Mathematics makes existence claims, but philosophers usually say those are never analytic [Hart,WD] |
| 13488 | Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD] |
| 5287 | Philosophical problems are resolved into empirical facts [Marx/Engels] |
| 13480 | Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD] |
| 13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
| 5303 | For the proletariate, law, morality and religion are just expressions of bourgeois interests [Marx/Engels] |
| 23872 | 'Society determines consciousness' is contradictory; society only exists in minds [Weil on Marx/Engels] |
| 5277 | Life is not determined by consciousness, but consciousness by life [Marx/Engels] |
| 13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
| 5280 | Language co-exists with consciousness, and makes it social [Marx/Engels] |
| 5281 | Consciousness is a social product [Marx/Engels] |
| 5276 | The nature of an individual coincides with what they produce and how they produce it [Marx/Engels] |
| 2854 | Prescriptivism says 'ought' without commitment to act is insincere, or weakly used [Hooker,B] |
| 21998 | Bourgeois interests create our morality, law and religion [Marx/Engels] |
| 2856 | Universal moral judgements imply the Golden Rule ('do as you would be done by') [Hooker,B] |
| 5289 | When aristocracy or the bourgeoisie dominate, certain values dominate with them [Marx/Engels] |
| 20883 | Modern utilitarians value knowledge, friendship, autonomy, and achievement, as well as pleasure [Hooker,B] |
| 20884 | Rule-utilitarians prevent things like torture, even on rare occasions when it seems best [Hooker,B] |
| 5274 | Young Hegelians proposed changing our present consciousness for liberating critical consciousness [Marx/Engels] |
| 21992 | Producing their own subsistence distinguishes men from animals [Marx/Engels] |
| 5275 | Men distinguish themselves from animals when they begin to produce their means of subsistence [Marx/Engels] |
| 5292 | Individuals are mutually hostile unless they group together in competition with other groups [Marx/Engels] |
| 5293 | Only in community are people able to cultivate their gifts, and therefore be free [Marx/Engels] |
| 5273 | Young Hegelians think consciousness is chains for men, where old Hegelians think it the bond of society [Marx/Engels] |
| 5282 | If the common interest imposes on the individual, his actions become alienated and enslaving [Marx/Engels] |
| 5283 | In communist society we are not trapped in one activity, but can act freely [Marx/Engels] |
| 5288 | The class controlling material production also controls mental production [Marx/Engels] |
| 5290 | The revolutionary class is opposed to 'class', and represents all of society [Marx/Engels] |
| 5294 | To assert themselves as individuals, the proletarians must overthrow the State [Marx/Engels] |
| 5302 | Modern governments are just bourgeois management committees [Marx/Engels] |
| 5304 | Communism aims to abolish not all property, but bourgeois property [Marx/Engels] |
| 5307 | Many of the bourgeois rights grievances are a form of self-defence [Marx/Engels] |
| 5285 | Slavery cannot be abolished without the steam-engine [Marx/Engels] |
| 5284 | Communism abolishes private property and dissolves the powerful world market [Marx/Engels] |
| 5306 | The free development of each should be the condition for the free development of all [Marx/Engels] |
| 5291 | The law says private property is the result of the general will [Marx/Engels] |
| 5305 | Communists want to rescue education from the ruling class [Marx/Engels] |
| 5279 | Human history must always be studied in relation to industry and exchange [Marx/Engels] |
| 5286 | Most historians are trapped in the illusions of their own epoch [Marx/Engels] |
| 5301 | The history of all existing society is the history of class struggles [Marx/Engels] |
| 20885 | Euthanasia is active or passive, and voluntary, non-voluntary or involuntary [Hooker,B] |
| 20882 | Euthanasia may not involve killing, so it is 'killing or not saving, out of concern for that person' [Hooker,B] |