93 ideas
| 13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
| 19073 | True philosophy aims at absolute unity, while our understanding sees only separation [Hegel] |
| 13477 | The problems are the monuments of philosophy [Hart,WD] |
| 15624 | Free thinking has no presuppositions [Hegel] |
| 15631 | The ideal of reason is the unification of abstract identity (or 'concept') and being [Hegel] |
| 15612 | Older metaphysics naively assumed that thought grasped things in themselves [Hegel] |
| 21768 | Logic is metaphysics, the science of things grasped in thoughts [Hegel] |
| 13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
| 21984 | We must break up the rigidity that our understanding has imposed [Hegel] |
| 22081 | Let thought follow its own course, and don't interfere [Hegel] |
| 15626 | Categories create objective experience, but are too conditioned by things to actually grasp them [Hegel] |
| 15616 | If truth is just non-contradiction, we must take care that our basic concepts aren't contradictory [Hegel] |
| 15615 | Older metaphysics became dogmatic, by assuming opposed assertions must be true and false [Hegel] |
| 21767 | Dialectic is seen in popular proverbs like 'pride comes before a fall' [Hegel] |
| 15638 | Dialectic is the moving soul of scientific progression, the principle which binds science together [Hegel] |
| 15639 | Socratic dialectic is subjective, but Plato made it freely scientific and objective [Hegel] |
| 19070 | Superficial truth is knowing how something is, which is consciousness of bare correctness [Hegel] |
| 5644 | In Hegel's logic it is concepts (rather than judgements or propositions) which are true or false [Hegel, by Scruton] |
| 19072 | In the deeper sense of truth, to be untrue resembles being bad; badness is untrue to a thing's nature [Hegel] |
| 19071 | The deeper sense of truth is a thing matching the idea of what it ought to be [Hegel] |
| 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] |
| 21595 | Excluded middle is the maxim of definite understanding, but just produces contradictions [Hegel] |
| 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] |
| 15628 | The idea that contradiction is essential to rational understanding is a key modern idea [Hegel] |
| 15629 | Tenderness for the world solves the antinomies; contradiction is in our reason, not in the essence of the world [Hegel] |
| 15630 | Antinomies are not just in four objects, but in all objects, all representations, all objects and all ideas [Hegel] |
| 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] |
| 15634 | Thought about particulars is done entirely through categories [Hegel] |
| 22078 | Even simple propositions about sensations are filled with categories [Hegel] |
| 21981 | The one substance is formless without the mediation of dialectical concepts [Hegel] |
| 15637 | Essence is the essential self-positing unity of immediacy and mediation [Hegel] |
| 15613 | Real cognition grasps a thing from within itself, and is not satisfied with mere predicates [Hegel] |
| 15636 | The Cogito is at the very centre of the entire concern of modern philosophy [Hegel] |
| 22300 | Existence is just a set of relationships [Hegel] |
| 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] |
| 15609 | The sensible is distinguished from thought by being about singular things [Hegel] |
| 15625 | Sense perception is secondary and dependent, while thought is independent and primitive [Hegel] |
| 15619 | Empiricism made particular knowledge possible, and blocked wild claims [Hegel] |
| 15620 | Empiricism contains the important idea that we should see knowledge for ourselves, and be part of it [Hegel] |
| 15622 | Empiricism unknowingly contains and uses a metaphysic, which underlies its categories [Hegel] |
| 15621 | Empiricism of the finite denies the supersensible, and can only think with formal abstraction [Hegel] |
| 15632 | The Humean view stops us thinking about perception, and finding universals and necessities in it [Hegel] |
| 15623 | Humean scepticism, unlike ancient Greek scepticism, accepts the truth of experience as basic [Hegel] |
| 15617 | In abstraction, beyond finitude, freedom and necessity must exist together [Hegel] |
| 15608 | The act of thinking is the bringing forth of universals [Hegel] |
| 21986 | Hegel's system has a vast number of basic concepts [Hegel, by Moore,AW] |
| 15607 | We don't think with concepts - we think the concepts [Hegel] |
| 15610 | Active thought about objects produces the universal, which is what is true and essential of it [Hegel] |
| 13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| 15614 | Old metaphysics tried to grasp eternal truths through causal events, which is impossible [Hegel] |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| 15635 | The older conception of God was emptied of human features, to make it worthy of the Infinite [Hegel] |
| 21980 | God is the absolute thing, and also the absolute person [Hegel] |
| 15618 | If God is the abstract of Supremely Real Essence, then God is a mere Beyond, and unknowable [Hegel] |
| 15633 | We establish unification of the Ideal by the ontological proof, deriving being from abstraction of thinking [Hegel] |