84 ideas
7914 | To try to be wise all on one's own is folly [Rochefoucauld] |
24146 | All the major problems were formulated before Socrates [Nietzsche] |
13466 | We are all post-Kantians, because he set the current agenda for philosophy [Hart,WD] |
24142 | What matters is how humans can be developed [Nietzsche] |
13477 | The problems are the monuments of philosophy [Hart,WD] |
24143 | Thinkers might agree some provisional truths, as methodological assumptions [Nietzsche] |
24125 | Aristotle enjoyed the sham generalities of a system, as the peak of happiness! [Nietzsche] |
13515 | To study abstract problems, some knowledge of set theory is essential [Hart,WD] |
24147 | Thoughts are uncertain, and are just occasions for interpretation [Nietzsche] |
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] |
24137 | Mathematics is just accurate inferences from definitions, and doesn't involve objects [Nietzsche] |
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] |
24131 | There is no 'being'; it is just the opposition to nothingness [Nietzsche] |
13488 | Mass words do not have plurals, or numerical adjectives, or use 'fewer' [Hart,WD] |
24151 | I only want thinking that is anchored in body, senses and earth [Nietzsche] |
24150 | We can only understand through concepts, which subsume particulars in generalities [Nietzsche] |
13480 | Fregean self-evidence is an intrinsic property of basic truths, rules and definitions [Hart,WD] |
24138 | Strongly believed a priori is not certain; it may just be a feature of our existence [Nietzsche] |
13476 | The failure of key assumptions in geometry, mereology and set theory throw doubt on the a priori [Hart,WD] |
24130 | An affirmative belief is present in every basic sense impression [Nietzsche] |
24124 | We now have innumerable perspectives to draw on [Nietzsche] |
7118 | La Rochefoucauld's idea of disguised self-love implies an unconscious mind [Rochefoucauld, by Sartre] |
24145 | Mind is a mechanism of abstraction and simplification, aimed at control [Nietzsche] |
24144 | A cognitive mechanism wanting to know itself is absurd! [Nietzsche] |
24139 | A 'person' is just one possible abstraction from a bundle of qualities [Nietzsche] |
24133 | I have perfected fatalism, as recurrence and denial of the will [Nietzsche] |
24152 | Fate is inspiring, if you understand you are part of it [Nietzsche] |
24129 | We start with images, then words, and then concepts, to which emotions attach [Nietzsche] |
13475 | The Fregean concept of GREEN is a function assigning true to green things, and false to the rest [Hart,WD] |
24127 | Judging actions by intentions - like judging painters by their thoughts! [Nietzsche] |
24149 | Values need a perspective, of preserving some aspect of life [Nietzsche] |
7912 | Judging by effects, love looks more like hatred than friendship [Rochefoucauld] |
24148 | If you love something, it is connected with everything, so all must be affirmed as good [Nietzsche] |
24135 | Egoism should not assume that all egos are equal [Nietzsche] |
7915 | Supreme cleverness is knowledge of the real value of things [Rochefoucauld] |
7917 | Realising our future misery is a kind of happiness [Rochefoucauld] |
24132 | After Socrates virtue is misunderstood, as good for all, not for individuals [Nietzsche] |
7913 | Virtue doesn't go far without the support of vanity [Rochefoucauld] |
24126 | We contain multitudes of characters, which can brought into the open [Nietzsche] |
7916 | True friendship is even rarer than true love [Rochefoucauld] |
9299 | We are bored by people to whom we ourselves are boring [Rochefoucauld] |
24136 | Who can endure the thought of eternal recurrence? [Nietzsche] |
24154 | If you want one experience repeated, you must want all of them [Nietzsche] |
24153 | Humans are determined by community, so its preservation is their most valued drive [Nietzsche] |
24134 | There is always slavery, whether we like it or not [Nietzsche] |
24128 | After history following God, or a people, or an idea, we now see it in terms of animals [Nietzsche] |
24140 | Cause and effect is a hypothesis, based on our supposed willing of actions [Nietzsche] |
24141 | Having a sense of time presupposes absolute time [Nietzsche] |