116 ideas
224 | When questions are doubtful we should concentrate not on objects but on ideas of the intellect [Plato] |
232 | Opposites are as unlike as possible [Plato] |
8937 | Plato's 'Parmenides' is the greatest artistic achievement of the ancient dialectic [Hegel on Plato] |
9955 | Contextual definitions replace a complete sentence containing the expression [George/Velleman] |
10031 | Impredicative definitions quantify over the thing being defined [George/Velleman] |
10098 | The 'power set' of A is all the subsets of A [George/Velleman] |
10099 | The 'ordered pair' <a, b>, for two sets a and b, is the set {{a, b},{a}} [George/Velleman] |
10101 | Cartesian Product A x B: the set of all ordered pairs in which a∈A and b∈B [George/Velleman] |
10103 | Grouping by property is common in mathematics, usually using equivalence [George/Velleman] |
10104 | 'Equivalence' is a reflexive, symmetric and transitive relation; 'same first letter' partitions English words [George/Velleman] |
10096 | Even the elements of sets in ZFC are sets, resting on the pure empty set [George/Velleman] |
10097 | Axiom of Extensionality: for all sets x and y, if x and y have the same elements then x = y [George/Velleman] |
10100 | Axiom of Pairing: for all sets x and y, there is a set z containing just x and y [George/Velleman] |
17900 | The Axiom of Reducibility made impredicative definitions possible [George/Velleman] |
10109 | ZFC can prove that there is no set corresponding to the concept 'set' [George/Velleman] |
10108 | As a reduction of arithmetic, set theory is not fully general, and so not logical [George/Velleman] |
10111 | Asserting Excluded Middle is a hallmark of realism about the natural world [George/Velleman] |
10129 | A 'model' is a meaning-assignment which makes all the axioms true [George/Velleman] |
10105 | Differences between isomorphic structures seem unimportant [George/Velleman] |
10119 | Consistency is a purely syntactic property, unlike the semantic property of soundness [George/Velleman] |
10126 | A 'consistent' theory cannot contain both a sentence and its negation [George/Velleman] |
10120 | Soundness is a semantic property, unlike the purely syntactic property of consistency [George/Velleman] |
10127 | A 'complete' theory contains either any sentence or its negation [George/Velleman] |
13986 | Plato found antinomies in ideas, Kant in space and time, and Bradley in relations [Plato, by Ryle] |
14150 | Plato's 'Parmenides' is perhaps the best collection of antinomies ever made [Russell on Plato] |
10106 | Rational numbers give answers to division problems with integers [George/Velleman] |
10102 | The integers are answers to subtraction problems involving natural numbers [George/Velleman] |
10107 | Real numbers provide answers to square root problems [George/Velleman] |
9946 | Logicists say mathematics is applicable because it is totally general [George/Velleman] |
10125 | The classical mathematician believes the real numbers form an actual set [George/Velleman] |
17899 | Second-order induction is stronger as it covers all concepts, not just first-order definable ones [George/Velleman] |
10128 | The Incompleteness proofs use arithmetic to talk about formal arithmetic [George/Velleman] |
17902 | A successor is the union of a set with its singleton [George/Velleman] |
10133 | Frege's Theorem shows the Peano Postulates can be derived from Hume's Principle [George/Velleman] |
10130 | Set theory can prove the Peano Postulates [George/Velleman] |
16150 | One is, so numbers exist, so endless numbers exist, and each one must partake of being [Plato] |
10089 | Talk of 'abstract entities' is more a label for the problem than a solution to it [George/Velleman] |
10131 | If mathematics is not about particulars, observing particulars must be irrelevant [George/Velleman] |
10092 | In the unramified theory of types, the types are objects, then sets of objects, sets of sets etc. [George/Velleman] |
10094 | The theory of types seems to rule out harmless sets as well as paradoxical ones. [George/Velleman] |
10095 | Type theory has only finitely many items at each level, which is a problem for mathematics [George/Velleman] |
17901 | Type theory prohibits (oddly) a set containing an individual and a set of individuals [George/Velleman] |
10114 | Bounded quantification is originally finitary, as conjunctions and disjunctions [George/Velleman] |
10134 | Much infinite mathematics can still be justified finitely [George/Velleman] |
10123 | The intuitionists are the idealists of mathematics [George/Velleman] |
10124 | Gödel's First Theorem suggests there are truths which are independent of proof [George/Velleman] |
229 | The one was and is and will be and was becoming and is becoming and will become [Plato] |
21821 | Plato's Parmenides has a three-part theory, of Primal One, a One-Many, and a One-and-Many [Plato, by Plotinus] |
221 | Absolute ideas, such as the Good and the Beautiful, cannot be known by us [Plato] |
223 | If you deny that each thing always stays the same, you destroy the possibility of discussion [Plato] |
227 | You must always mean the same thing when you utter the same name [Plato] |
210 | It would be absurd to think there were abstract Forms for vile things like hair, mud and dirt [Plato] |
220 | The concept of a master includes the concept of a slave [Plato] |
211 | If admirable things have Forms, maybe everything else does as well [Plato] |
219 | If absolute ideas existed in us, they would cease to be absolute [Plato] |
228 | Greatness and smallness must exist, to be opposed to one another, and come into being in things [Plato] |
16151 | Plato moves from Forms to a theory of genera and principles in his later work [Plato, by Frede,M] |
218 | Participation is not by means of similarity, so we are looking for some other method of participation [Plato] |
215 | If things partake of ideas, this implies either that everything thinks, or that everything actually is thought [Plato] |
212 | The whole idea of each Form must be found in each thing which participates in it [Plato] |
213 | Each idea is in all its participants at once, just as daytime is a unity but in many separate places at once [Plato] |
216 | If things are made alike by participating in something, that thing will be the absolute idea [Plato] |
217 | Nothing can be like an absolute idea, because a third idea intervenes to make them alike (leading to a regress) [Plato] |
214 | If absolute greatness and great things are seen as the same, another thing appears which makes them seem great [Plato] |
15851 | Parts must belong to a created thing with a distinct form [Plato] |
15846 | In Parmenides, if composition is identity, a whole is nothing more than its parts [Plato, by Harte,V] |
15849 | Plato says only a one has parts, and a many does not [Plato, by Harte,V] |
15850 | Anything which has parts must be one thing, and parts are of a one, not of a many [Plato] |
13259 | It seems that the One must be composed of parts, which contradicts its being one [Plato] |
15847 | Two things relate either as same or different, or part of a whole, or the whole of the part [Plato] |
7871 | Perceptual concepts can't just refer to what causes classification [Papineau] |
7852 | The only serious mind-brain theories now are identity, token identity, realization and supervenience [Papineau] |
7864 | Maybe mind and body do overdetermine acts, but are linked (for some reason) [Papineau] |
7873 | Young children can see that other individuals sometimes have false beliefs [Papineau] |
7874 | Do we understand other minds by simulation-theory, or by theory-theory? [Papineau] |
7882 | Researching phenomenal consciousness is peculiar, because the concepts involved are peculiar [Papineau] |
7854 | Whether octopuses feel pain is unclear, because our phenomenal concepts are too vague [Papineau] |
7889 | Our concept of consciousness is crude, and lacks theoretical articulation [Papineau] |
7891 | We can’t decide what 'conscious' means, so it is undecidable whether cats are conscious [Papineau] |
7890 | Maybe a creature is conscious if its mental states represent things in a distinct way [Papineau] |
7885 | The 'actualist' HOT theory says consciousness comes from actual higher judgements of mental states [Papineau] |
7886 | Actualist HOT theories imply that a non-conscious mental event could become conscious when remembered [Papineau] |
7887 | States are conscious if they could be the subject of higher-order mental judgements [Papineau] |
7888 | Higher-order judgements may be possible where the subject denies having been conscious [Papineau] |
7860 | The epiphenomenal relation of mind and brain is a 'causal dangler', unlike anything else [Papineau] |
7862 | Maybe minds do not cause actions, but do cause us to report our decisions [Papineau] |
7870 | Role concepts either name the realising property, or the higher property constituting the role [Papineau] |
7858 | If causes are basic particulars, this doesn't make conscious and physical properties identical [Papineau] |
7865 | Supervenience can be replaced by identifying mind with higher-order or disjunctional properties [Papineau] |
7892 | The completeness of physics is needed for mind-brain identity [Papineau] |
7879 | Mind-brain reduction is less explanatory, because phenomenal concepts lack causal roles [Papineau] |
20971 | Weak reduction of mind is to physical causes; strong reduction is also to physical laws [Papineau] |
7856 | It is absurd to think that physical effects are caused twice, so conscious causes must be physical [Papineau] |
7881 | Accept ontological monism, but conceptual dualism; we think in a different way about phenomenal thought [Papineau] |
7866 | Mary acquires new concepts; she previously thought about the same property using material concepts [Papineau] |
7850 | Thinking about a thing doesn't require activating it [Papineau] |
7851 | Consciousness affects bodily movement, so thoughts must be material states [Papineau] |
7884 | Most reductive accounts of representation imply broad content [Papineau] |
7863 | If content hinges on matters outside of you, how can it causally influence your actions? [Papineau] |
10110 | Corresponding to every concept there is a class (some of them sets) [George/Velleman] |
7883 | Verificationists tend to infer indefinite answers from undecidable questions [Papineau] |
7872 | Teleosemantics equates meaning with the item the concept is intended to track [Papineau] |
7869 | Truth conditions in possible worlds can't handle statements about impossibilities [Papineau] |
7868 | Thought content is possible worlds that make the thought true; if that includes the actual world, it's true [Papineau] |
222 | Only a great person can understand the essence of things, and an even greater person can teach it [Plato] |
225 | The unlimited has no shape and is endless [Plato] |
233 | Some things do not partake of the One [Plato] |
2062 | The only movement possible for the One is in space or in alteration [Plato] |
231 | Everything partakes of the One in some way [Plato] |
7853 | Causation is based on either events, or facts, or states of affairs [Papineau] |
7857 | Causes are instantiations of properties by particulars, or they are themselves basic particulars [Papineau] |
20976 | The completeness of physics cannot be proved [Papineau] |
20970 | Determinism is possible without a complete physics, if mental forces play a role [Papineau] |
20974 | Modern biological research, especially into the cell, has revealed no special new natural forces [Papineau] |
20975 | Quantum 'wave collapses' seem to violate conservation of energy [Papineau] |
234 | We couldn't discuss the non-existence of the One without knowledge of it [Plato] |