75 ideas
20121 | Grammar only reveals popular metaphysics [Nietzsche] |
9955 | Contextual definitions replace a complete sentence containing the expression [George/Velleman] |
10031 | Impredicative definitions quantify over the thing being defined [George/Velleman] |
24082 | Is the will to truth the desire to avoid deception? [Nietzsche] |
10098 | The 'power set' of A is all the subsets of A [George/Velleman] |
10101 | Cartesian Product A x B: the set of all ordered pairs in which a∈A and b∈B [George/Velleman] |
10099 | The 'ordered pair' <a, b>, for two sets a and b, is the set {{a, b},{a}} [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] |
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] |
20360 | We Germans value becoming and development more highly than mere being of what 'is' [Nietzsche] |
24077 | Necessity is thought to require an event, but is only an after-effect of the event [Nietzsche] |
20126 | The strength of knowledge is not its truth, but its entrenchment in our culture [Nietzsche] |
20119 | We became increasingly conscious of our sense impressions in order to communicate them [Nietzsche] |
20122 | We have no organ for knowledge or truth; we only 'know' what is useful to the human herd [Nietzsche] |
4423 | We assume causes, geometry, motion, bodies etc to live, but they haven't been proved [Nietzsche] |
6579 | Nietzsche's perspectivism says our worldview depends on our personality [Nietzsche, by Fogelin] |
24083 | It would be absurd to say we are only permitted our own single perspective [Nietzsche] |
20115 | All of our normal mental life could be conducted without consciousness [Nietzsche] |
20117 | Only the need for communication has led to consciousness developing [Nietzsche] |
20118 | Only our conscious thought is verbal, and this shows the origin of consciousness [Nietzsche] |
20116 | Most of our lives, even the important parts, take place outside of consciousness [Nietzsche] |
20120 | Whatever moves into consciousness becomes thereby much more superficial [Nietzsche] |
2932 | 'Know thyself' is impossible and ridiculous [Nietzsche] |
24078 | Thoughts cannot be fully reproduced in words [Nietzsche] |
24081 | Most of our intellectual activity is unconscious [Nietzsche] |
10110 | Corresponding to every concept there is a class (some of them sets) [George/Velleman] |
2933 | Why do you listen to the voice of your conscience? [Nietzsche] |
20141 | Higher human beings see and hear far more than others, and do it more thoughtfully [Nietzsche] |
24076 | A morality ranks human drives and actions, for the sake of the herd, and subordinating individuals [Nietzsche] |
22471 | Nietzsche thought it 'childish' to say morality isn't binding because it varies between cultures [Nietzsche, by Foot] |
2935 | No two actions are the same [Nietzsche] |
20198 | Many virtues are harmful traps, but that is why other people praise them [Nietzsche] |
4275 | You cannot advocate joyful wisdom while rejecting pity, because the two are complementary [Scruton on Nietzsche] |
2934 | To see one's own judgement as a universal law is selfish [Nietzsche] |
24080 | We should give style to our character - by applying an artistic plan to its strengths and weaknesses [Nietzsche] |
20125 | The ethical teacher exists to give purpose to what happens necessarily and without purpose [Nietzsche] |
9306 | To ward off boredom at any cost is vulgar [Nietzsche] |
24079 | The best life is the dangerous life [Nietzsche] |
2936 | Imagine if before each of your actions you had to accept repeating the action over and over again [Nietzsche] |
6842 | Nietzsche says facing up to the eternal return of meaninglessness is the response to nihilism [Nietzsche, by Critchley] |
19399 | Prime matter is nothing when it is at rest [Leibniz] |
2931 | God is dead, and we have killed him [Nietzsche] |