41 ideas
10859 | A set is 'well-ordered' if every subset has a first element [Clegg] |
10857 | Set theory made a closer study of infinity possible [Clegg] |
10864 | Any set can always generate a larger set - its powerset, of subsets [Clegg] |
10872 | Extensionality: Two sets are equal if and only if they have the same elements [Clegg] |
10875 | Pairing: For any two sets there exists a set to which they both belong [Clegg] |
10876 | Unions: There is a set of all the elements which belong to at least one set in a collection [Clegg] |
10878 | Infinity: There exists a set of the empty set and the successor of each element [Clegg] |
10877 | Powers: All the subsets of a given set form their own new powerset [Clegg] |
10879 | Choice: For every set a mechanism will choose one member of any non-empty subset [Clegg] |
10871 | Axiom of Existence: there exists at least one set [Clegg] |
10874 | Specification: a condition applied to a set will always produce a new set [Clegg] |
10880 | Mathematics can be 'pure' (unapplied), 'real' (physically grounded); or 'applied' (just applicable) [Clegg] |
10860 | An ordinal number is defined by the set that comes before it [Clegg] |
10861 | Beyond infinity cardinals and ordinals can come apart [Clegg] |
10854 | Transcendental numbers can't be fitted to finite equations [Clegg] |
10858 | By adding an axis of imaginary numbers, we get the useful 'number plane' instead of number line [Clegg] |
10853 | Either lack of zero made early mathematics geometrical, or the geometrical approach made zero meaningless [Clegg] |
10866 | Cantor's account of infinities has the shaky foundation of irrational numbers [Clegg] |
10869 | The Continuum Hypothesis is independent of the axioms of set theory [Clegg] |
10862 | The 'continuum hypothesis' says aleph-one is the cardinality of the reals [Clegg] |
411 | If we succeed in speaking the truth, we cannot know we have done it [Xenophanes] |
412 | If God had not created honey, men would say figs are sweeter [Xenophanes] |
22673 | Wherever there is a small community, the association of the people is natural [Tocqueville] |
22676 | The people are just individuals, and only present themselves as united to foreigners [Tocqueville] |
22679 | Vast empires are bad for well-being and freedom, though they may promote glory [Tocqueville] |
22680 | People would be much happier and freer in small nations [Tocqueville] |
22675 | In American judges rule according to the Constitution, not the law [Tocqueville] |
22677 | A monarchical family is always deeply concerned with the interests of the state [Tocqueville] |
22683 | Despots like to see their own regulations ignored, by themselves and their agents [Tocqueville] |
22669 | Aristocracy is constituted by inherited landed property [Tocqueville] |
22674 | In Europe it is thought that local government is best handled centrally [Tocqueville] |
22678 | An election, and its lead up time, are always a national crisis [Tocqueville] |
22682 | Universal suffrage is no guarantee of wise choices [Tocqueville] |
22670 | Slavery undermines the morals and energy of a society [Tocqueville] |
22681 | The liberty of the press is more valuable for what it prevents than what it promotes [Tocqueville] |
22672 | It is admirable to elevate the humble to the level of the great, but the opposite is depraved [Tocqueville] |
22671 | Equality can only be established by equal rights for all (or no rights for anyone) [Tocqueville] |
1640 | The basic Eleatic belief was that all things are one [Xenophanes, by Plato] |
3055 | Xenophanes said the essence of God was spherical and utterly inhuman [Xenophanes, by Diog. Laertius] |
407 | Mortals believe gods are born, and have voices and clothes just like mortals [Xenophanes] |
408 | Ethiopian gods have black hair, and Thracian gods have red hair [Xenophanes] |