122 ideas
19695 | The devil was wise as an angel, and lost no knowledge when he rebelled [Whitcomb] |
23657 | The existence of tensed verbs shows that not all truths are necessary truths [Reid] |
23655 | An ad hominem argument is good, if it is shown that the man's principles are inconsistent [Reid] |
15901 | Trying to represent curves, we study arbitrary functions, leading to the ordinals, which produces set theory [Cantor, by Lavine] |
15946 | Cantor developed sets from a progression into infinity by addition, multiplication and exponentiation [Cantor, by Lavine] |
9616 | A set is a collection into a whole of distinct objects of our intuition or thought [Cantor] |
13444 | Cantor's Theorem: for any set x, its power set P(x) has more members than x [Cantor, by Hart,WD] |
18098 | Cantor proved that all sets have more subsets than they have members [Cantor, by Bostock] |
15505 | If a set is 'a many thought of as one', beginners should protest against singleton sets [Cantor, by Lewis] |
10701 | Cantor showed that supposed contradictions in infinity were just a lack of clarity [Cantor, by Potter] |
10865 | The continuum is the powerset of the integers, which moves up a level [Cantor, by Clegg] |
17831 | Cantor gives informal versions of ZF axioms as ways of getting from one set to another [Cantor, by Lake] |
13016 | The Axiom of Union dates from 1899, and seems fairly obvious [Cantor, by Maddy] |
14199 | Cantor's sets were just collections, but Dedekind's were containers [Cantor, by Oliver/Smiley] |
10082 | There are infinite sets that are not enumerable [Cantor, by Smith,P] |
13483 | Cantor's Paradox: the power set of the universe must be bigger than the universe, yet a subset of it [Cantor, by Hart,WD] |
8710 | The powerset of all the cardinal numbers is required to be greater than itself [Cantor, by Friend] |
15910 | Cantor named the third realm between the finite and the Absolute the 'transfinite' [Cantor, by Lavine] |
15905 | Cantor proved the points on a plane are in one-to-one correspondence to the points on a line [Cantor, by Lavine] |
9983 | Cantor took the ordinal numbers to be primary [Cantor, by Tait] |
17798 | Cantor presented the totality of natural numbers as finite, not infinite [Cantor, by Mayberry] |
9971 | Cantor introduced the distinction between cardinals and ordinals [Cantor, by Tait] |
9892 | Cantor showed that ordinals are more basic than cardinals [Cantor, by Dummett] |
15911 | Ordinals are generated by endless succession, followed by a limit ordinal [Cantor, by Lavine] |
14136 | A cardinal is an abstraction, from the nature of a set's elements, and from their order [Cantor] |
15906 | Cantor tried to prove points on a line matched naturals or reals - but nothing in between [Cantor, by Lavine] |
11015 | Cantor's diagonal argument proved you can't list all decimal numbers between 0 and 1 [Cantor, by Read] |
15903 | A real is associated with an infinite set of infinite Cauchy sequences of rationals [Cantor, by Lavine] |
18251 | Irrational numbers are the limits of Cauchy sequences of rational numbers [Cantor, by Lavine] |
15902 | Irrationals and the Dedekind Cut implied infinite classes, but they seemed to have logical difficulties [Cantor, by Lavine] |
15908 | It was Cantor's diagonal argument which revealed infinities greater than that of the real numbers [Cantor, by Lavine] |
13464 | Cantor proposes that there won't be a potential infinity if there is no actual infinity [Cantor, by Hart,WD] |
10112 | The naturals won't map onto the reals, so there are different sizes of infinity [Cantor, by George/Velleman] |
15896 | Cantor needed Power Set for the reals, but then couldn't count the new collections [Cantor, by Lavine] |
17889 | CH: An infinite set of reals corresponds 1-1 either to the naturals or to the reals [Cantor, by Koellner] |
13447 | Cantor: there is no size between naturals and reals, or between a set and its power set [Cantor, by Hart,WD] |
10883 | Cantor's Continuum Hypothesis says there is a gap between the natural and the real numbers [Cantor, by Horsten] |
8733 | The Continuum Hypothesis says there are no sets between the natural numbers and reals [Cantor, by Shapiro] |
13528 | Continuum Hypothesis: there are no sets between N and P(N) [Cantor, by Wolf,RS] |
9555 | Continuum Hypothesis: no cardinal greater than aleph-null but less than cardinality of the continuum [Cantor, by Chihara] |
15893 | Cantor's theory concerns collections which can be counted, using the ordinals [Cantor, by Lavine] |
18174 | Cantor extended ordinals into the transfinite, and they can thus measure infinite cardinalities [Cantor, by Maddy] |
18173 | Cardinality strictly concerns one-one correspondence, to test infinite sameness of size [Cantor, by Maddy] |
9992 | The 'extension of a concept' in general may be quantitatively completely indeterminate [Cantor] |
10232 | Property extensions outstrip objects, so shortage of objects caused the Caesar problem [Cantor, by Shapiro] |
18176 | Pure mathematics is pure set theory [Cantor] |
8631 | Cantor says that maths originates only by abstraction from objects [Cantor, by Frege] |
23634 | Accepting the existence of anything presupposes the notion of existence [Reid] |
23664 | Powers are quite distinct and simple, and so cannot be defined [Reid] |
23669 | Thinkers say that matter has intrinsic powers, but is also passive and acted upon [Reid] |
23666 | It is obvious that there could not be a power without a subject which possesses it [Reid] |
23651 | Universals are not objects of sense and cannot be imagined - but can be conceived [Reid] |
23650 | Only individuals exist [Reid] |
23649 | No one thinks two sheets possess a single whiteness, but all agree they are both white [Reid] |
23647 | Objects have an essential constitution, producing its qualities, which we are too ignorant to define [Reid] |
1350 | Continuity is needed for existence, otherwise we would say a thing existed after it ceased to exist [Reid] |
21322 | We treat slowly changing things as identical for the sake of economy in language [Reid] |
21320 | Identity is familiar to common sense, but very hard to define [Reid] |
1367 | Identity can only be affirmed of things which have a continued existence [Reid] |
11874 | Real identity admits of no degrees [Reid] |
11958 | Impossibilites are easily conceived in mathematics and geometry [Reid, by Molnar] |
23659 | If someone denies that he is thinking when he is conscious of it, we can only laugh [Reid] |
23662 | The existence of ideas is no more obvious than the existence of external objects [Reid] |
23661 | We are only aware of other beings through our senses; without that, we are alone in the universe [Reid] |
23635 | Truths are self-evident to sensible persons who understand them clearly without prejudice [Reid] |
7631 | Sensation is not committed to any external object, but perception is [Reid] |
23637 | Primary qualities are the object of mathematics [Reid] |
23638 | Secondary qualities conjure up, and are confused with, the sensations which produce them [Reid] |
23639 | It is unclear whether a toothache is in the mind or in the tooth, but the word has a single meaning [Reid] |
6492 | Reid is seen as the main direct realist of the eighteenth century [Reid, by Robinson,H] |
23633 | Many truths seem obvious, and point to universal agreement - which is what we find [Reid] |
23654 | In obscure matters the few must lead the many, but the many usually lead in common sense [Reid] |
23644 | Without memory we could have no concept of duration [Reid] |
23643 | We all trust our distinct memories (but not our distinct imaginings) [Reid] |
23660 | The theory of ideas, popular with philosophers, means past existence has to be proved [Reid] |
23641 | People dislike believing without evidence, and try to avoid it [Reid] |
23642 | If non-rational evidence reaches us, it is reason which then makes use of it [Reid] |
23549 | We treat testimony with a natural trade off of belief and caution [Reid, by Fricker,M] |
1356 | A person is a unity, and doesn't come in degrees [Reid] |
23658 | Consciousness is an indefinable and unique operation [Reid] |
23665 | Consciousness is the power of mind to know itself, and minds are grounded in powers [Reid] |
1359 | Personal identity is the basis of all rights, obligations and responsibility [Reid] |
21319 | I can hardly care about rational consequence if it wasn't me conceiving the antecedent [Reid] |
21323 | The identity of a thief is only known by similarity, but memory gives certainty in our own case [Reid] |
21321 | Memory reveals my past identity - but so does testimony of other witnesses [Reid] |
21324 | If consciousness is transferable 20 persons can be 1; forgetting implies 1 can be 20 [Reid] |
21325 | Boy same as young man, young man same as old man, old man not boy, if forgotten! [Reid] |
21327 | If a stolen horse is identified by similitude, its identity is not therefore merely similitude [Reid] |
1366 | If consciousness is personal identity, it is continually changing [Reid] |
1352 | Thoughts change continually, but the self doesn't [Reid] |
23681 | The first motion or effect cannot be produced necessarily, so the First Cause must be a free agent [Reid] |
23676 | A willed action needs reasonable understanding of what is to be done [Reid] |
23668 | Our own nature attributes free determinations to our own will [Reid] |
23680 | We are morally free, because we experience it, we are accountable, and we pursue projects [Reid] |
23652 | We must first conceive things before we can consider them [Reid] |
23656 | The structure of languages reveals a uniformity in basic human opinions [Reid] |
23630 | Only philosophers treat ideas as objects [Reid] |
8715 | Infinities expand the bounds of the conceivable; we explore concepts to explore conceivability [Cantor, by Friend] |
23648 | First we notice and name attributes ('abstracting'); then we notice that subjects share them ('generalising') [Reid] |
23653 | If you can't distinguish the features of a complex object, your notion of it would be a muddle [Reid] |
23640 | Only mature minds can distinguish the qualities of a body [Reid] |
13454 | Cantor says (vaguely) that we abstract numbers from equal sized sets [Hart,WD on Cantor] |
9145 | We form the image of a cardinal number by a double abstraction, from the elements and from their order [Cantor] |
23629 | The ambiguity of words impedes the advancement of knowledge [Reid] |
23646 | Reference is by name, or a term-plus-circumstance, or ostensively, or by description [Reid] |
23645 | A word's meaning is the thing conceived, as fixed by linguistic experts [Reid] |
20051 | Reid said that agent causation is a unique type of causation [Reid, by Stout,R] |
23678 | A motive is merely an idea, like advice, and not a force for action [Reid] |
23663 | There are axioms of taste - such as a general consensus about a beautiful face [Reid] |
23674 | If an attempted poisoning results in benefits, we still judge the agent a poisoner [Reid] |
23675 | We shouldn't do to others what would be a wrong to us in similar circumstances [Reid] |
23672 | To be virtuous, we must care about duty [Reid] |
23673 | Every worthy man has a principle of honour, and knows what is honourable [Reid] |
23632 | Similar effects come from similar causes, and causes are only what are sufficient for the effects [Reid] |
8383 | Day and night are constantly conjoined, but they don't cause one another [Reid, by Crane] |
23677 | We all know that mere priority or constant conjunction do not have to imply causation [Reid] |
23667 | Regular events don't imply a cause, without an innate conviction of universal causation [Reid] |
23679 | The principle of the law of nature is that matter is passive, and is acted upon [Reid] |
23670 | Scientists don't know the cause of magnetism, and only discover its regulations [Reid] |
23671 | Laws are rules for effects, but these need a cause; rules of navigation don't navigate [Reid] |
10863 | Cantor proved that three dimensions have the same number of points as one dimension [Cantor, by Clegg] |
13465 | Only God is absolutely infinite [Cantor, by Hart,WD] |