71 ideas
17774 | Definitions make our intuitions mathematically useful [Mayberry] |
17773 | Proof shows that it is true, but also why it must be true [Mayberry] |
17795 | Set theory can't be axiomatic, because it is needed to express the very notion of axiomatisation [Mayberry] |
17796 | There is a semi-categorical axiomatisation of set-theory [Mayberry] |
17800 | The misnamed Axiom of Infinity says the natural numbers are finite in size [Mayberry] |
17801 | The set hierarchy doesn't rely on the dubious notion of 'generating' them [Mayberry] |
17803 | Limitation of size is part of the very conception of a set [Mayberry] |
17786 | The mainstream of modern logic sees it as a branch of mathematics [Mayberry] |
17788 | First-order logic only has its main theorems because it is so weak [Mayberry] |
17791 | Only second-order logic can capture mathematical structure up to isomorphism [Mayberry] |
17787 | Big logic has one fixed domain, but standard logic has a domain for each interpretation [Mayberry] |
17790 | No Löwenheim-Skolem logic can axiomatise real analysis [Mayberry] |
17779 | 'Classificatory' axioms aim at revealing similarity in morphology of structures [Mayberry] |
17778 | Axiomatiation relies on isomorphic structures being essentially the same [Mayberry] |
17780 | 'Eliminatory' axioms get rid of traditional ideal and abstract objects [Mayberry] |
17789 | No logic which can axiomatise arithmetic can be compact or complete [Mayberry] |
5109 | The fast runner must always reach the point from which the slower runner started [Zeno of Elea, by Aristotle] |
1507 | We don't have time for infinite quantity, but we do for infinite divisibility, because time is also divisible [Aristotle on Zeno of Elea] |
1512 | Zeno is wrong that one grain of millet makes a sound; why should one grain achieve what the whole bushel does? [Aristotle on Zeno of Elea] |
1508 | Zeno's arrow paradox depends on the assumption that time is composed of nows [Aristotle on Zeno of Elea] |
17784 | Real numbers can be eliminated, by axiom systems for complete ordered fields [Mayberry] |
17782 | Greek quantities were concrete, and ratio and proportion were their science [Mayberry] |
17781 | Real numbers were invented, as objects, to simplify and generalise 'quantity' [Mayberry] |
17799 | Cantor's infinite is an absolute, of all the sets or all the ordinal numbers [Mayberry] |
17797 | Cantor extended the finite (rather than 'taming the infinite') [Mayberry] |
17775 | If proof and definition are central, then mathematics needs and possesses foundations [Mayberry] |
17776 | The ultimate principles and concepts of mathematics are presumed, or grasped directly [Mayberry] |
17777 | Foundations need concepts, definition rules, premises, and proof rules [Mayberry] |
17804 | Axiom theories can't give foundations for mathematics - that's using axioms to explain axioms [Mayberry] |
17792 | 1st-order PA is only interesting because of results which use 2nd-order PA [Mayberry] |
17793 | It is only 2nd-order isomorphism which suggested first-order PA completeness [Mayberry] |
17794 | Set theory is not just first-order ZF, because that is inadequate for mathematics [Mayberry] |
17802 | We don't translate mathematics into set theory, because it comes embodied in that way [Mayberry] |
17805 | Set theory is not just another axiomatised part of mathematics [Mayberry] |
16588 | I prefer a lack of form to mean non-existence, than to think of some quasi-existence [Augustine] |
22979 | Three main questions seem to be whether a thing is, what it is, and what sort it is [Augustine] |
17785 | Real numbers as abstracted objects are now treated as complete ordered fields [Mayberry] |
3912 | I must exist in order to be mistaken, so that even if I am mistaken, I can't be wrong about my own existence [Augustine] |
22167 | Our images of bodies are not produced by the bodies, but by our own minds [Augustine, by Aquinas] |
22117 | Our minds grasp reality by direct illumination (rather than abstraction from experience) [Augustine, by Matthews] |
22981 | Mind and memory are the same, as shown in 'bear it in mind' or 'it slipped from mind' [Augustine] |
22980 | Memory contains innumerable principles of maths, as well as past sense experiences [Augustine] |
22983 | We would avoid remembering sorrow or fear if that triggered the emotions afresh [Augustine] |
22977 | I can distinguish different smells even when I am not experiencing them [Augustine] |
22982 | Why does joy in my mind make me happy, but joy in my memory doesn't? [Augustine] |
22978 | Memory is so vast that I cannot recognise it as part of my mind [Augustine] |
22984 | Without memory I could not even speak of myself [Augustine] |
5982 | If the future does not exist, how can prophets see it? [Augustine] |
6683 | The contact of spirit and body is utterly amazing, and incomprehensible [Augustine] |
22976 | Memories are preserved separately, according to category [Augustine] |
22118 | Augustine created the modern concept of the will [Augustine, by Matthews] |
4348 | Love, and do what you will [Augustine] |
7821 | Pagans produced three hundred definitions of the highest good [Augustine, by Grayling] |
22985 | Everyone wants happiness [Augustine] |
22119 | Augustine said (unusually) that 'ought' does not imply 'can' [Augustine, by Matthews] |
454 | If there are many things they must have a finite number, but there must be endless things between them [Zeno of Elea] |
455 | That which moves, moves neither in the place in which it is, nor in that in which it is not [Zeno of Elea] |
1511 | If everything is in a place, what is the place in? Place doesn't exist [Zeno of Elea, by Simplicius] |
5984 | Maybe time is an extension of the mind [Augustine] |
22888 | To be aware of time it can only exist in the mind, as memory or anticipation [Augustine, by Bardon] |
5980 | How can ten days ahead be a short time, if it doesn't exist? [Augustine] |
5979 | If the past is no longer, and the future is not yet, how can they exist? [Augustine] |
5981 | The whole of the current year is not present, so how can it exist? [Augustine] |
5978 | I know what time is, until someone asks me to explain it [Augustine] |
5983 | I disagree with the idea that time is nothing but cosmic movement [Augustine] |
5977 | Heaven and earth must be created, because they are subject to change [Augustine] |
22887 | If God existed before creation, why would a perfect being desire to change things? [Augustine, by Bardon] |
5976 | If God is outside time in eternity, can He hear prayers? [Augustine] |
16702 | All things are in the present time to God [Augustine] |
22116 | Augustine identified Donatism, Pelagianism and Manicheism as the main heresies [Augustine, by Matthews] |
19338 | Augustine said evil does not really exist, and evil is a limitation in goodness [Augustine, by Perkins] |