63 ideas
8797 | The negation of all my beliefs about my current headache would be fully coherent [Sosa] |
8877 | We can't attain a coherent system by lopping off any beliefs that won't fit [Sosa] |
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] |
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] |
10089 | Talk of 'abstract entities' is more a label for the problem than a solution to it [George/Velleman] |
8884 | The phenomenal concept of an eleven-dot pattern does not include the concept of eleven [Sosa] |
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] |
8443 | Mereological essentialism says an entity must have exactly those parts [Sosa] |
8878 | It is acceptable to say a supermarket door 'knows' someone is approaching [Sosa] |
8880 | In reducing arithmetic to self-evident logic, logicism is in sympathy with rationalism [Sosa] |
8881 | Most of our knowledge has insufficient sensory support [Sosa] |
8794 | There are very few really obvious truths, and not much can be proved from them [Sosa] |
8882 | Perception may involve thin indexical concepts, or thicker perceptual concepts [Sosa] |
8883 | Do beliefs only become foundationally justified if we fully attend to features of our experience? [Sosa] |
8885 | Some features of a thought are known directly, but others must be inferred [Sosa] |
8876 | Much propositional knowledge cannot be formulated, as in recognising a face [Sosa] |
8796 | A single belief can trail two regresses, one terminating and one not [Sosa] |
8799 | If mental states are not propositional, they are logically dumb, and cannot be foundations [Sosa] |
8795 | Mental states cannot be foundational if they are not immune to error [Sosa] |
8879 | Fully comprehensive beliefs may not be knowledge [Sosa] |
8798 | Vision causes and justifies beliefs; but to some extent the cause is the justification [Sosa] |
10110 | Corresponding to every concept there is a class (some of them sets) [George/Velleman] |
22745 | Pherecydes said the first principle and element is earth [Pherecydes, by Sext.Empiricus] |
8442 | What law would explain causation in the case of causing a table to come into existence? [Sosa] |
8445 | The necessitated is not always a result or consequence of the necessitator [Sosa] |
8444 | Where is the necessary causation in the three people being tall making everybody tall? [Sosa] |
5883 | Pherecydes was the first to say that the soul is eternal [Pherecydes, by Cicero] |