138 ideas
15447 | We shouldn't always follow where the argument leads! [Lewis on Plato] |
14122 | Analysis gives us nothing but the truth - but never the whole truth [Russell] |
14109 | The study of grammar is underestimated in philosophy [Russell] |
14165 | Analysis falsifies, if when the parts are broken down they are not equivalent to their sum [Russell] |
243 | It is foolish to quarrel with the mind's own reasoning processes [Plato] |
241 | We ought to follow where the argument leads us [Plato] |
21264 | Mortals are incapable of being fully rational [Plato] |
14115 | Definition by analysis into constituents is useless, because it neglects the whole [Russell] |
14159 | In mathematics definitions are superfluous, as they name classes, and it all reduces to primitives [Russell] |
14148 | Infinite regresses have propositions made of propositions etc, with the key term reappearing [Russell] |
18002 | As well as a truth value, propositions have a range of significance for their variables [Russell] |
251 | Truth has the supreme value, for both gods and men [Plato] |
14102 | What is true or false is not mental, and is best called 'propositions' [Russell] |
14176 | "The death of Caesar is true" is not the same proposition as "Caesar died" [Russell] |
14113 | The null class is a fiction [Russell] |
15894 | Russell invented the naïve set theory usually attributed to Cantor [Russell, by Lavine] |
14126 | Order rests on 'between' and 'separation' [Russell] |
14127 | Order depends on transitive asymmetrical relations [Russell] |
14121 | The part-whole relation is ultimate and indefinable [Russell] |
14106 | Implication cannot be defined [Russell] |
14108 | It would be circular to use 'if' and 'then' to define material implication [Russell] |
14167 | The only classes are things, predicates and relations [Russell] |
14105 | There seem to be eight or nine logical constants [Russell] |
18722 | Negations are not just reversals of truth-value, since that can happen without negation [Wittgenstein on Russell] |
14104 | Constants are absolutely definite and unambiguous [Russell] |
14114 | Variables don't stand alone, but exist as parts of propositional functions [Russell] |
14137 | 'Any' is better than 'all' where infinite classes are concerned [Russell] |
14149 | The Achilles Paradox concerns the one-one correlation of infinite classes [Russell] |
15895 | Russell discovered the paradox suggested by Burali-Forti's work [Russell, by Lavine] |
14151 | Pure geometry is deductive, and neutral over what exists [Russell] |
14152 | In geometry, Kant and idealists aimed at the certainty of the premisses [Russell] |
14154 | Geometry throws no light on the nature of actual space [Russell] |
14153 | In geometry, empiricists aimed at premisses consistent with experience [Russell] |
14155 | Two points have a line joining them (descriptive), a distance (metrical), and a whole line (projective) [Russell, by PG] |
18254 | Russell's approach had to treat real 5/8 as different from rational 5/8 [Russell, by Dummett] |
14144 | Ordinals result from likeness among relations, as cardinals from similarity among classes [Russell] |
14128 | Some claim priority for the ordinals over cardinals, but there is no logical priority between them [Russell] |
14129 | Ordinals presuppose two relations, where cardinals only presuppose one [Russell] |
14132 | Properties of numbers don't rely on progressions, so cardinals may be more basic [Russell] |
14139 | Transfinite ordinals don't obey commutativity, so their arithmetic is quite different from basic arithmetic [Russell] |
14142 | Ordinals are types of series of terms in a row, rather than the 'nth' instance [Russell] |
14141 | Ordinals are defined through mathematical induction [Russell] |
14145 | For Cantor ordinals are types of order, not numbers [Russell] |
14146 | We aren't sure if one cardinal number is always bigger than another [Russell] |
14135 | Real numbers are a class of rational numbers (and so not really numbers at all) [Russell] |
14123 | Some quantities can't be measured, and some non-quantities are measurable [Russell] |
14158 | Quantity is not part of mathematics, where it is replaced by order [Russell] |
14120 | Counting explains none of the real problems about the foundations of arithmetic [Russell] |
14118 | We can define one-to-one without mentioning unity [Russell] |
14133 | There are cardinal and ordinal theories of infinity (while continuity is entirely ordinal) [Russell] |
14119 | We do not currently know whether, of two infinite numbers, one must be greater than the other [Russell] |
14134 | Infinite numbers are distinguished by disobeying induction, and the part equalling the whole [Russell] |
14143 | ω names the whole series, or the generating relation of the series of ordinal numbers [Russell] |
14138 | You can't get a new transfinite cardinal from an old one just by adding finite numbers to it [Russell] |
14140 | For every transfinite cardinal there is an infinite collection of transfinite ordinals [Russell] |
14124 | Axiom of Archimedes: a finite multiple of a lesser magnitude can always exceed a greater [Russell] |
7530 | Russell tried to replace Peano's Postulates with the simple idea of 'class' [Russell, by Monk] |
18246 | Dedekind failed to distinguish the numbers from other progressions [Shapiro on Russell] |
14125 | Finite numbers, unlike infinite numbers, obey mathematical induction [Russell] |
14147 | Denying mathematical induction gave us the transfinite [Russell] |
14116 | Numbers were once defined on the basis of 1, but neglected infinities and + [Russell] |
14117 | Numbers are properties of classes [Russell] |
9977 | Ordinals can't be defined just by progression; they have intrinsic qualities [Russell] |
14162 | Mathematics doesn't care whether its entities exist [Russell] |
14103 | Pure mathematics is the class of propositions of the form 'p implies q' [Russell] |
21555 | For 'x is a u' to be meaningful, u must be one range of individuals (or 'type') higher than x [Russell] |
18003 | In 'x is a u', x and u must be of different types, so 'x is an x' is generally meaningless [Russell, by Magidor] |
11010 | Being is what belongs to every possible object of thought [Russell] |
14161 | Many things have being (as topics of propositions), but may not have actual existence [Russell] |
14173 | What exists has causal relations, but non-existent things may also have them [Russell] |
14163 | Four classes of terms: instants, points, terms at instants only, and terms at instants and points [Russell] |
21341 | Philosophers of logic and maths insisted that a vocabulary of relations was essential [Russell, by Heil] |
10586 | 'Reflexiveness' holds between a term and itself, and cannot be inferred from symmetry and transitiveness [Russell] |
10585 | Symmetrical and transitive relations are formally like equality [Russell] |
7781 | I call an object of thought a 'term'. This is a wide concept implying unity and existence. [Russell] |
14166 | Unities are only in propositions or concepts, and nothing that exists has unity [Russell] |
14164 | The only unities are simples, or wholes composed of parts [Russell] |
14112 | A set has some sort of unity, but not enough to be a 'whole' [Russell] |
21259 | To grasp a thing we need its name, its definition, and what it really is [Plato] |
14170 | Change is obscured by substance, a thing's nature, subject-predicate form, and by essences [Russell] |
14107 | Terms are identical if they belong to all the same classes [Russell] |
11849 | It at least makes sense to say two objects have all their properties in common [Wittgenstein on Russell] |
22303 | It makes no sense to say that a true proposition could have been false [Russell] |
21260 | Soul is what is defined by 'self-generating motion' [Plato] |
276 | My individuality is my soul, which carries my body around [Plato] |
10583 | Abstraction principles identify a common property, which is some third term with the right relation [Russell] |
10582 | The principle of Abstraction says a symmetrical, transitive relation analyses into an identity [Russell] |
10584 | A certain type of property occurs if and only if there is an equivalence relation [Russell] |
14110 | Proposition contain entities indicated by words, rather than the words themselves [Russell] |
19164 | If propositions are facts, then false and true propositions are indistinguishable [Davidson on Russell] |
19157 | Russell said the proposition must explain its own unity - or else objective truth is impossible [Russell, by Davidson] |
14111 | A proposition is a unity, and analysis destroys it [Russell] |
249 | People who value beauty above virtue insult the soul by placing the body above it [Plato] |
468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
265 | An action is only just if it is performed by someone with a just character and outlook [Plato] |
269 | Attempted murder is like real murder, but we should respect the luck which avoided total ruin [Plato] |
240 | It would be strange if the gods rewarded those who experienced the most pleasure in life [Plato] |
264 | The conquest of pleasure is the noblest victory of all [Plato] |
253 | Every crime is the result of excessive self-love [Plato] |
263 | The only worthwhile life is one devoted to physical and moral perfection [Plato] |
4332 | Virtue is a concord of reason and emotion, with pleasure and pain trained to correct ends [Plato] |
248 | A serious desire for moral excellence is very rare indeed [Plato] |
235 | Virtue is the aim of all laws [Plato] |
277 | The Guardians must aim to discover the common element in the four cardinal virtues [Plato] |
254 | Excessive laughter and tears must be avoided [Plato] |
266 | Injustice is the mastery of the soul by bad feelings, even if they do not lead to harm [Plato] |
256 | Virtue and great wealth are incompatible [Plato] |
242 | The best people are produced where there is no excess of wealth or poverty [Plato] |
245 | Totalitarian states destroy friendships and community spirit [Plato] |
239 | Education in virtue produces citizens who are active but obedient [Plato] |
262 | Men and women should qualify equally for honours on merit [Plato] |
1402 | Friendship is impossible between master and slave, even if they are made equal [Plato] |
236 | Sound laws achieve the happiness of those who observe them [Plato] |
259 | Justice is granting the equality which unequals deserve [Plato] |
238 | Children's games should channel their pleasures into adult activity [Plato] |
260 | Control of education is the key office of state, and should go to the best citizen [Plato] |
257 | Mathematics has the widest application of any subject on the curriculum [Plato] |
4331 | Education is channelling a child's feelings into the right course before it understands why [Plato] |
250 | The best way to educate the young is not to rebuke them, but to set a good example [Plato] |
275 | Creation is not for you; you exist for the sake of creation [Plato] |
14175 | We can drop 'cause', and just make inferences between facts [Russell] |
14172 | Moments and points seem to imply other moments and points, but don't cause them [Russell] |
14174 | The laws of motion and gravitation are just parts of the definition of a kind of matter [Russell] |
14168 | Occupying a place and change are prior to motion, so motion is just occupying places at continuous times [Russell] |
14171 | Force is supposed to cause acceleration, but acceleration is a mathematical fiction [Russell] |
14160 | Space is the extension of 'point', and aggregates of points seem necessary for geometry [Russell] |
14156 | Mathematicians don't distinguish between instants of time and points on a line [Russell] |
14169 | The 'universe' can mean what exists now, what always has or will exist [Russell] |
273 | Movement is transmitted through everything, and it must have started with self-generated motion [Plato] |
8004 | In 'The Laws', to obey the law is to be obey god [Plato, by MacIntyre] |
21257 | Self-generating motion is clearly superior to all other kinds of motion [Plato] |
21258 | The only possible beginning for the endless motions of reality is something self-generated [Plato] |
21261 | Self-moving soul has to be the oldest thing there is [Plato] |
274 | Soul must be the cause of all the opposites, such as good and evil or beauty and ugliness [Plato] |
21263 | If all the motions of nature reflect calculations of reason, then the best kind of soul must direct it [Plato] |
278 | If astronomical movements are seen as necessary instead of by divine will, this leads to atheism [Plato] |
21265 | The heavens must be full of gods, controlling nature either externally or from within [Plato] |
21262 | There must be at least two souls controlling the cosmos, one doing good, the other the opposite [Plato] |