82 ideas
21422 | Moral self-knowledge is the beginning of all human wisdom [Kant] |
13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
21970 | Philosophy attains its goal if one person feels perfect accord between their system and experience [Fichte] |
13477 | The problems are the monuments of philosophy [Hart,WD] |
21408 | For any subject, its system of non-experiential concepts needs a metaphysics [Kant] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
21416 | Philosophers should not offer multiple proofs - suggesting the weakness of each of them [Kant] |
6912 | For Fichte there is no God outside the ego, and 'our religion is reason' [Fichte, by Feuerbach] |
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] |
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] |
21410 | That a concept is not self-contradictory does not make what it represents possible [Kant] |
21973 | Fichte believed in things-in-themselves [Fichte, by Moore,AW] |
21914 | We can deduce experience from self-consciousness, without the thing-in-itself [Fichte] |
20951 | The absolute I divides into consciousness, and a world which is not-I [Fichte, by Bowie] |
21964 | Reason arises from freedom, so philosophy starts from the self, and not from the laws of nature [Fichte] |
21968 | Abandon the thing-in-itself; things only exist in relation to our thinking [Fichte] |
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] |
21421 | Within nature man is unimportant, but as moral person he is above any price [Kant] |
21965 | Spinoza could not actually believe his determinism, because living requires free will [Fichte] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
21415 | Duty is impossible without prior moral feeling, conscience, love and self-respect [Kant] |
21409 | Moral principles do not involve feelings [Kant] |
21431 | The love of man is required in order to present the world as a beautiful and perfect moral whole [Kant] |
21437 | All morality directs the will to love of others' ends, and respect for others' rights [Kant] |
21429 | The duty of love is to makes the ends of others one's own [Kant] |
21411 | A duty of virtue is a duty which is also an end [Kant] |
21413 | Virtue is strong maxims for duty [Kant] |
21414 | The supreme principle of virtue is to find universal laws for ends [Kant] |
21436 | We are obliged to show the social virtues, but at least they make a virtuous disposition fashionable [Kant] |
21419 | If virtue becomes a habit, that is a loss of the freedom needed for adopting maxims [Kant] |
21417 | How do we distinguish a mean? The extremes can involve quite different maxims [Kant] |
21420 | If virtue is the mean between vices, then virtue is just the vanishing of vice [Kant] |
21418 | There is one principle of virtues; the virtues are distinguished by their objects [Kant] |
21425 | We can love without respect, and show respect without love [Kant] |
21430 | Disrespect is using a person as a mere means to my own ends [Kant] |
21427 | Respect is limiting our self-esteem by attending to the human dignity of other persons [Kant] |
21426 | Love urges us to get closer to people, but respect to keep our distance [Kant] |
21428 | Respect is purely negative (of not exalting oneself over others), and is thus a duty of Right [Kant] |
21434 | We must respect the humanity even in a vicious criminal [Kant] |
21412 | Humans are distinguished from animals by their capacity to set themselves any sort of end [Kant] |
21435 | Man is both social, and unsociable [Kant] |
21433 | Violation of rights deserves punishment, which is vengeance, rather than restitution [Kant] |
21423 | Men can only have duties to those who qualify as persons [Kant] |
21424 | Cruelty to animals is bad because it dulls our empathy for pain in humans [Kant] |