75 ideas
13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
13477 | The problems are the monuments of philosophy [Hart,WD] |
20388 | 'Necessary' conditions are requirements, and 'sufficient' conditions are guarantees [Davies,S] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
1812 | All discussion is full of uncertainty and contradiction (Mode 11) [Agrippa, by Diog. Laertius] |
1811 | Proofs often presuppose the thing to be proved (Mode 15) [Agrippa, by Diog. Laertius] |
1813 | All reasoning endlessly leads to further reasoning (Mode 12) [Agrippa, by Diog. Laertius] |
1815 | Reasoning needs arbitrary faith in preliminary hypotheses (Mode 14) [Agrippa, by Diog. Laertius] |
20389 | A definition of a thing gives all the requirements which add up to a guarantee of it [Davies,S] |
20391 | Feminists warn that ideologies use timeless objective definitions as a tool of repression [Davies,S] |
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] |
13461 | We can choose from finite and evident sets, but not from infinite opaque ones [Hart,WD] |
13462 | With the Axiom of Choice every set can be well-ordered [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] |
13457 | A 'partial ordering' is irreflexive and transitive; the sets are ordered, but not the subsets [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] |
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] |
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] |
13513 | Models are ways the world might be from a first-order point of view [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] |
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] |
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] |
8850 | Agrippa's Trilemma: justification is infinite, or ends arbitrarily, or is circular [Agrippa, by Williams,M] |
1814 | Everything is perceived in relation to another thing (Mode 13) [Agrippa, by Diog. Laertius] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
20387 | Aesthetic experience involves perception, but also imagination and understanding [Davies,S] |
20385 | The faculty of 'taste' was posited to explain why only some people had aesthetic appreciation [Davies,S] |
20386 | The sublime is negative in awareness of insignificance, and positive in showing understanding [Davies,S] |
20384 | The idea that art forms are linked into a single concept began in the 1740s [Davies,S] |
20390 | Defining art as representation or expression or form were all undermined by the avant-garde [Davies,S] |
20392 | 'Aesthetic functionalism' says art is what is intended to create aesthetic experiences [Davies,S] |
20405 | Music may be expressive by being 'associated' with other emotional words or events [Davies,S] |
20403 | It seems unlikely that sad music expresses a composer's sadness; it takes ages to write [Davies,S] |
20393 | The 'institutional' theory says art is just something appropriately placed in the 'artworld' [Davies,S] |
20402 | Music is too definite to be put into words (not too indefinite!) [Davies,S] |
20395 | The title of a painting can be vital, and the artist decrees who the portrait represents [Davies,S] |
20396 | We must know what the work is meant to be, to evaluate the artist's achievement [Davies,S] |
20399 | Intentionalism says either meaning just is intention, or ('moderate') meaning is successful intention [Davies,S] |
20401 | The meaning is given by the audience's best guess at the author's intentions [Davies,S] |
20398 | Art that is multiply instanced may require at least one instance [Davies,S] |
20397 | If we could perfectly clone the Mona Lisa, the original would still be special [Davies,S] |
20404 | Music isn't just sad because it makes the listener feel sad [Davies,S] |
22704 | Immorality may or may not be an artistic defect [Davies,S] |
22705 | If the depiction of evil is glorified, that is an artistic flaw [Davies,S] |
22706 | A work which seeks approval for immorality, but alienates the audience, is a failure [Davies,S] |
22707 | It is an artistic defect if excessive moral outrage distorts the story, and narrows our sympathies [Davies,S] |