83 ideas
1695 | Without extensive examination firm statements are hard, but studying the difficulties is profitable [Aristotle] |
1698 | Both sides of contraries need not exist (as health without sickness, white without black) [Aristotle] |
1697 | The contrary of good is bad, but the contrary of bad is either good or another evil [Aristotle] |
8721 | An 'impredicative' definition seems circular, because it uses the term being defined [Friend] |
8680 | Classical definitions attempt to refer, but intuitionist/constructivist definitions actually create objects [Friend] |
3678 | Reductio ad absurdum proves an idea by showing that its denial produces contradiction [Friend] |
11034 | The differentiae of genera which are different are themselves different in kind [Aristotle] |
8705 | Anti-realists see truth as our servant, and epistemically contrained [Friend] |
18367 | A true existence statement has its truth caused by the existence of the thing [Aristotle] |
8713 | In classical/realist logic the connectives are defined by truth-tables [Friend] |
8708 | Double negation elimination is not valid in intuitionist logic [Friend] |
8694 | Free logic was developed for fictional or non-existent objects [Friend] |
8665 | A 'proper subset' of A contains only members of A, but not all of them [Friend] |
8672 | A 'powerset' is all the subsets of a set [Friend] |
8677 | Set theory makes a minimum ontological claim, that the empty set exists [Friend] |
8666 | Infinite sets correspond one-to-one with a subset [Friend] |
8682 | Major set theories differ in their axioms, and also over the additional axioms of choice and infinity [Friend] |
11033 | Predications of predicates are predications of their subjects [Aristotle] |
8709 | The law of excluded middle is syntactic; it just says A or not-A, not whether they are true or false [Friend] |
8711 | Intuitionists read the universal quantifier as "we have a procedure for checking every..." [Friend] |
8675 | Paradoxes can be solved by talking more loosely of 'classes' instead of 'sets' [Friend] |
8674 | The Burali-Forti paradox asks whether the set of all ordinals is itself an ordinal [Friend] |
8667 | The 'integers' are the positive and negative natural numbers, plus zero [Friend] |
8668 | The 'rational' numbers are those representable as fractions [Friend] |
8670 | A number is 'irrational' if it cannot be represented as a fraction [Friend] |
11044 | One is prior to two, because its existence is implied by two [Aristotle] |
8661 | The natural numbers are primitive, and the ordinals are up one level of abstraction [Friend] |
8664 | Cardinal numbers answer 'how many?', with the order being irrelevant [Friend] |
8671 | The 'real' numbers (rationals and irrationals combined) is the Continuum, which has no gaps [Friend] |
11042 | Parts of a line join at a point, so it is continuous [Aristotle] |
8662 | The first limit ordinal is omega (greater, but without predecessor), and the second is twice-omega [Friend] |
8663 | Raising omega to successive powers of omega reveal an infinity of infinities [Friend] |
8669 | Between any two rational numbers there is an infinite number of rational numbers [Friend] |
8676 | Is mathematics based on sets, types, categories, models or topology? [Friend] |
11041 | Some quantities are discrete, like number, and others continuous, like lines, time and space [Aristotle] |
8678 | Most mathematical theories can be translated into the language of set theory [Friend] |
8702 | In structuralism the number 8 is not quite the same in different structures, only equivalent [Friend] |
8701 | The number 8 in isolation from the other numbers is of no interest [Friend] |
8699 | Are structures 'ante rem' (before reality), or are they 'in re' (grounded in physics)? [Friend] |
8695 | Structuralism focuses on relations, predicates and functions, with objects being inessential [Friend] |
8696 | Structuralist says maths concerns concepts about base objects, not base objects themselves [Friend] |
8700 | 'In re' structuralism says that the process of abstraction is pattern-spotting [Friend] |
8681 | The big problem for platonists is epistemic: how do we perceive, intuit, know or detect mathematical facts? [Friend] |
8712 | Mathematics should be treated as true whenever it is indispensable to our best physical theory [Friend] |
8716 | Formalism is unconstrained, so cannot indicate importance, or directions for research [Friend] |
8706 | Constructivism rejects too much mathematics [Friend] |
8707 | Intuitionists typically retain bivalence but reject the law of excluded middle [Friend] |
11286 | Primary being must be more than mere indeterminate ultimate subject of predication [Politis on Aristotle] |
1700 | There are six kinds of change: generation, destruction, increase, diminution, alteration, change of place [Aristotle] |
1699 | A thing is prior to another if it implies its existence [Aristotle] |
18366 | Of interdependent things, the prior one causes the other's existence [Aristotle] |
11035 | There are ten basic categories for thinking about things [Aristotle] |
13121 | Substance,Quantity,Quality,Relation,Place,Time,Being-in-a-position,Having,Doing,Being affected [Aristotle, by Westerhoff] |
3311 | The categories (substance, quality, quantity, relation, action, passion, place, time) peter out inconsequentially [Benardete,JA on Aristotle] |
16116 | Aristotle derived categories as answers to basic questions about nature, size, quality, location etc. [Aristotle, by Gill,ML] |
21345 | Aristotle said relations are not substances, so (if they exist) they must be accidents [Aristotle, by Heil] |
16155 | Aristotle promoted the importance of properties and objects (rather than general and particular) [Aristotle, by Frede,M] |
11032 | Some things said 'of' a subject are not 'in' the subject [Aristotle] |
11038 | We call them secondary 'substances' because they reveal the primary substances [Aristotle] |
16739 | Four species of quality: states, capacities, affects, and forms [Aristotle, by Pasnau] |
11037 | Colour must be in an individual body, or it is not embodied [Aristotle] |
16154 | Aristotle gave up his earlier notion of individuals, because it relied on universals [Aristotle, by Frede,M] |
8704 | Structuralists call a mathematical 'object' simply a 'place in a structure' [Friend] |
12351 | Genus and species are substances, because only they reveal the primary substance [Aristotle, by Wedin] |
11040 | A single substance can receive contrary properties [Aristotle] |
1694 | Substances have no opposites, and don't come in degrees (including if the substance is a man) [Aristotle] |
16091 | Is primary substance just an ultimate subject, or some aspect of a complex body? [Aristotle, by Gill,ML] |
11280 | Primary being is 'that which lies under', or 'particular substance' [Aristotle, by Politis] |
11036 | A 'primary' substance is in each subject, with species or genera as 'secondary' substances [Aristotle] |
16140 | Secondary substances do have subjects, so they are not ultimate in the ontology [Aristotle, by Frede,M] |
10965 | In earlier Aristotle the substances were particulars, not kinds [Aristotle, by Lawson-Tancred] |
8287 | Earlier Aristotle had objects as primary substances, but later he switched to substantial form [Aristotle, by Lowe] |
12350 | Things are called 'substances' because they are subjects for everything else [Aristotle] |
11039 | A primary substance reveals a 'this', which is an individual unit [Aristotle] |
12361 | Primary substances are ontological in 'Categories', and explanatory in 'Metaphysics' [Aristotle, by Wedin] |
3315 | Aristotle denigrates the category of relation, but for modern absolutists self-relation is basic [Benardete,JA on Aristotle] |
8685 | Studying biology presumes the laws of chemistry, and it could never contradict them [Friend] |
8688 | Concepts can be presented extensionally (as objects) or intensionally (as a characterization) [Friend] |
12349 | Only what can be said of many things is a predicable [Aristotle, by Wedin] |
11837 | Some predicates signify qualification of a substance, others the substance itself [Aristotle] |
11043 | It is not possible for fire to be cold or snow black [Aristotle] |
1696 | Change goes from possession to loss (as in baldness), but not the other way round [Aristotle] |
17366 | Virtually all modern views of speciation rest on relational rather than intrinsic features [Okasha] |