75 ideas
13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
8927 | Philosophy moves essentially in the element of universality [Hegel] |
21776 | Philosophy aims to reveal the necessity and rationality of the categories of nature and spirit [Hegel, by Houlgate] |
13477 | The problems are the monuments of philosophy [Hart,WD] |
22077 | Metaphysics is the lattice which makes incoming material intelligible [Hegel] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
8935 | Without philosophy, science is barren and futile [Hegel] |
22082 | Truth does not appear by asserting reasons and then counter-reasons [Hegel] |
22035 | The structure of reason is a social and historical achievement [Hegel, by Pinkard] |
8932 | Truth does not come from giving reasons for and against propositions [Hegel] |
13469 | Tarski showed how we could have a correspondence theory of truth, without using 'facts' [Hart,WD] |
7077 | The true is the whole [Hegel] |
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] |
15611 | I develop philosophical science from the simplest appearance of immediate consciousness [Hegel, by Hegel] |
8934 | Being is Thought [Hegel] |
8928 | The Absolute is not supposed to be comprehended, but felt and intuited [Hegel] |
8929 | In the Absolute everything is the same [Hegel] |
21774 | Genuine idealism is seeing the ideal structure of the world [Hegel, by Houlgate] |
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] |
21773 | Experience is immediacy, unity, forces, self-awareness, reason, culture, absolute being [Hegel, by Houlgate] |
22033 | Hegel tried to avoid Kant's dualism of neutral intuitions and imposed concepts [Hegel, by Pinkard] |
21771 | Consciousness derives its criterion of knowledge from direct knowledge of its own being [Hegel] |
20741 | Consciousness is shaped dialectically, by opposing forces and concepts [Hegel, by Aho] |
21770 | Consciousness is both of objects, and of itself [Hegel] |
5647 | Hegel claims knowledge of self presupposes desire, and hence objects [Hegel, by Scruton] |
5648 | For Hegel knowledge of self presupposes objects, and also a public and moral social world [Hegel, by Scruton] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
8930 | The in-itself must become for-itself, which requires self-consciousness [Hegel] |
21756 | All revolutions result from spirit changing its categories, to achieve a deeper understanding [Hegel] |
8936 | Human nature only really exists in an achieved community of minds [Hegel] |
22034 | Modern life needs individuality, but must recognise that human agency is social [Hegel, by Pinkard] |
21987 | History is the progress of the consciousness of freedom [Hegel] |
8931 | The movement of pure essences constitutes the nature of scientific method [Hegel] |
8933 | Science confronts the inner necessities of objects [Hegel] |
21775 | The God of revealed religion can only be understood through pure speculative knowledge [Hegel] |
6917 | God is the essence of thought, abstracted from the thinker [Hegel, by Feuerbach] |
6915 | Hegel made the last attempt to restore Christianity, which philosophy had destroyed [Hegel, by Feuerbach] |