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] |
15477 | Ontology is highly abstract physics, containing placeholders and exclusions [Martin,CB] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
15471 | Truth is a relation between a representation ('bearer') and part of the world ('truthmaker') [Martin,CB] |
6343 | For Russell, both propositions and facts are arrangements of objects, so obviously they correspond [Horwich on Russell] |
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] |
13458 | A partial ordering becomes 'total' if any two members of its field are comparable [Hart,WD] |
13460 | 'Well-ordering' must have a least member, so it does the natural numbers but not the integers [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] |
13512 | Modern model theory begins with the proof of Los's Conjecture in 1962 [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] |
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] |
13491 | The axiom of infinity with separation gives a least limit ordinal ω [Hart,WD] |
13463 | There are at least as many infinite cardinals as transfinite ordinals (because they will map) [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] |
15484 | A property is a combination of a disposition and a quality [Martin,CB] |
15478 | Properties are the respects in which objects resemble, which places them in classes [Martin,CB] |
15483 | Properties are ways particular things are, and so they are tied to the identity of their possessor [Martin,CB] |
15480 | Objects are not bundles of tropes (which are ways things are, not parts of things) [Martin,CB] |
15489 | A property that cannot interact is worse than inert - it isn't there at all [Martin,CB] |
15487 | If unmanifested partnerless dispositions are still real, and are not just qualities, they can explain properties [Martin,CB] |
15479 | Properties endow a ball with qualities, and with powers or dispositions [Martin,CB] |
15488 | Qualities and dispositions are aspects of properties - what it exhibits, and what it does [Martin,CB] |
15469 | Dispositions in action can be destroyed, be recovered, or remain unchanged [Martin,CB] |
15467 | Powers depend on circumstances, so can't be given a conditional analysis [Martin,CB] |
15466 | 'The wire is live' can't be analysed as a conditional, because a wire can change its powers [Martin,CB] |
15476 | Structural properties involve dispositionality, so cannot be used to explain it [Martin,CB] |
15465 | Structures don't explain dispositions, because they consist of dispositions [Martin,CB] |
15481 | I favour the idea of a substratum for properties; spacetime seems to be just a bearer of properties [Martin,CB] |
15474 | Properly understood, wholes do no more causal work than their parts [Martin,CB] |
15486 | Only abstract things can have specific and full identity specifications [Martin,CB] |
15475 | The concept of 'identity' must allow for some changes in properties or parts [Martin,CB] |
15472 | It is pointless to say possible worlds are truthmakers, and then deny that possible worlds exist [Martin,CB] |
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] |
15492 | Explanations are mind-dependent, theory-laden, and interest-relative [Martin,CB] |
15495 | Analogy works, as when we eat food which others seem to be relishing [Martin,CB] |
15493 | Memory requires abstraction, as reminders of what cannot be fully remembered [Martin,CB] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
7534 | In 1906, Russell decided that propositions did not, after all, exist [Russell, by Monk] |
15485 | Instead of a cause followed by an effect, we have dispositions in reciprocal manifestation [Martin,CB] |
15491 | Causation should be explained in terms of dispositions and manifestations [Martin,CB] |
15468 | Causal counterfactuals are just clumsy linguistic attempts to indicate dispositions [Martin,CB] |
15470 | Causal laws are summaries of powers [Martin,CB] |
15482 | We can't think of space-time as empty and propertyless, and it seems to be a substratum [Martin,CB] |