89 ideas
| 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] |
| 8705 | Anti-realists see truth as our servant, and epistemically contrained [Friend] |
| 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] |
| 8709 | The law of excluded middle is syntactic; it just says A or not-A, not whether they are true or false [Friend] |
| 4098 | The theory of descriptions supports internalism, since they are thinkable when the object is non-existent [Crane] |
| 8711 | Intuitionists read the universal quantifier as "we have a procedure for checking every..." [Friend] |
| 6007 | If you know your father, but don't recognise your father veiled, you know and don't know the same person [Eubulides, by Dancy,R] |
| 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] |
| 6006 | If you say truly that you are lying, you are lying [Eubulides, by Dancy,R] |
| 6008 | Removing one grain doesn't destroy a heap, so a heap can't be destroyed [Eubulides, by Dancy,R] |
| 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] |
| 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] |
| 8663 | Raising omega to successive powers of omega reveal an infinity of infinities [Friend] |
| 8662 | The first limit ordinal is omega (greater, but without predecessor), and the second is twice-omega [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] |
| 8678 | Most mathematical theories can be translated into the language of set theory [Friend] |
| 8701 | The number 8 in isolation from the other numbers is of no interest [Friend] |
| 8702 | In structuralism the number 8 is not quite the same in different structures, only equivalent [Friend] |
| 8699 | Are structures 'ante rem' (before reality), or are they 'in re' (grounded in physics)? [Friend] |
| 8696 | Structuralist says maths concerns concepts about base objects, not base objects themselves [Friend] |
| 8695 | Structuralism focuses on relations, predicates and functions, with objects being inessential [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] |
| 4077 | Aesthetic properties of thing supervene on their physical properties [Crane] |
| 4078 | Constitution (as in a statue constituted by its marble) is supervenience without identity [Crane] |
| 8386 | Events are picked out by descriptions, and facts by whole sentences [Crane] |
| 4082 | The distinction between 'resultant' properties (weight) and 'emergent' properties is a bit vague [Crane] |
| 4083 | If mental properties are emergent they add a new type of causation, and physics is not complete [Crane] |
| 4079 | Properties are causes [Crane] |
| 8704 | Structuralists call a mathematical 'object' simply a 'place in a structure' [Friend] |
| 4068 | Traditional substance is separate from properties and capable of independent existence [Crane] |
| 4097 | Maybe there are two kinds of belief - 'de re' beliefs and 'de dicto' beliefs [Crane] |
| 4096 | Maybe beliefs don't need to be conscious, if you are not conscious of the beliefs guiding your actions [Crane] |
| 4093 | Many cases of knowing how can be expressed in propositional terms (like how to get somewhere) [Crane] |
| 4108 | Phenol-thio-urea tastes bitter to three-quarters of people, but to the rest it is tasteless, so which is it? [Crane] |
| 4105 | The traditional supports for the sense datum theory were seeing double and specks before one's eyes [Crane] |
| 4104 | One can taste that the wine is sour, and one can also taste the sourness of the wine [Crane] |
| 4101 | If we smell something we are aware of the smell separately, but we don't perceive a 'look' when we see [Crane] |
| 4102 | The problems of perception disappear if it is a relation to an intentional state, not to an object or sense datum [Crane] |
| 4109 | If perception is much richer than our powers of description, this suggests that it is non-conceptual [Crane] |
| 4103 | The adverbial theory of perceptions says it is the experiences which have properties, not the objects [Crane] |
| 4065 | Is knowledge just a state of mind, or does it also involve the existence of external things? [Crane] |
| 4092 | The core of the consciousness problem is the case of Mary, zombies, and the Hard Question [Crane] |
| 4087 | Intentionalism does not require that all mental states be propositional attitudes [Crane] |
| 4095 | Object-directed attitudes like love are just as significant as propositional attitudes [Crane] |
| 4106 | If someone removes their glasses the content of experience remains, but the quality changes [Crane] |
| 4089 | Pains have a region of the body as their intentional content, not some pain object [Crane] |
| 4090 | Weak intentionalism says qualia are extra properties; strong intentionalism says they are intentional [Crane] |
| 4107 | With inverted qualia a person's experiences would change, but their beliefs remain the same [Crane] |
| 4069 | Descartes did not think of minds as made of a substance, because they are not divisible [Crane] |
| 4074 | Functionalism defines mental states by their causal properties, which rules out epiphenomenalism [Crane] |
| 4091 | The problems of misrepresentation and error have dogged physicalist reductions of intentionality [Crane] |
| 4070 | Properties dualism says mental properties are distinct from physical, despite a single underlying substance [Crane] |
| 4084 | Non-reductive physicalism seeks an explanation of supervenience, but emergentists accept it as basic [Crane] |
| 4080 | If mental supervenes on the physical, then every physical cause will be accompanied by a mental one [Crane] |
| 4075 | Identity theory is either of particular events, or of properties, depending on your theory of causation [Crane] |
| 4085 | Physicalism may be the source of the mind-body problem, rather than its solution [Crane] |
| 8685 | Studying biology presumes the laws of chemistry, and it could never contradict them [Friend] |
| 4073 | Overdetermination occurs if two events cause an effect, when each would have caused it alone [Crane] |
| 4072 | The completeness of physics must be an essential component of any physicalist view of mind [Crane] |
| 4094 | Experience teaches us propositions, because we can reason about our phenomenal experience [Crane] |
| 4100 | The Twin Earth argument depends on reference being determined by content, which may be false. [Crane] |
| 4067 | Broad content entails the existence of the object of the thought [Crane] |
| 4063 | In intensional contexts, truth depends on how extensions are conceived. [Crane] |
| 8688 | Concepts can be presented extensionally (as objects) or intensionally (as a characterization) [Friend] |
| 4071 | Causation can be seen in counterfactual terms, or as increased probability, or as energy flow [Crane] |
| 8387 | A cause has its effects in virtue of its properties [Crane] |
| 4076 | Causes are properties, not events, because properties are what make a difference in a situation [Crane] |
| 8384 | The regularity theory explains a causal event by other items than the two that are involved [Crane] |
| 4066 | It seems that 'exists' could sometimes be a predicate [Crane] |