78 ideas
| 23948 | Wisdom needs both thought and passion, with each reflecting on the other [Solomon] |
| 5988 | Anaximander produced the first philosophy book (and maybe the first book) [Anaximander, by Bodnár] |
| 23942 | Philosophy is creating an intellectual conceptual structure for life [Solomon] |
| 23945 | Reason is actually passions, guided by perspicacious reflection [Solomon] |
| 1496 | The earth is stationary, because it is in the centre, and has no more reason to move one way than another [Anaximander, by Aristotle] |
| 10073 | There cannot be a set theory which is complete [Smith,P] |
| 10616 | Second-order arithmetic can prove new sentences of first-order [Smith,P] |
| 10074 | A 'total function' maps every element to one element in another set [Smith,P] |
| 10612 | An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P] |
| 10605 | Two functions are the same if they have the same extension [Smith,P] |
| 10075 | A 'partial function' maps only some elements to another set [Smith,P] |
| 10076 | The 'range' of a function is the set of elements in the output set created by the function [Smith,P] |
| 10615 | The Comprehension Schema says there is a property only had by things satisfying a condition [Smith,P] |
| 10595 | A 'theorem' of a theory is a sentence derived from the axioms using the proof system [Smith,P] |
| 10602 | A 'natural deduction system' has no axioms but many rules [Smith,P] |
| 10613 | No nice theory can define truth for its own language [Smith,P] |
| 10079 | A 'bijective' function has one-to-one correspondence in both directions [Smith,P] |
| 10077 | A 'surjective' ('onto') function creates every element of the output set [Smith,P] |
| 10078 | An 'injective' ('one-to-one') function creates a distinct output element from each original [Smith,P] |
| 10070 | If everything that a theory proves is true, then it is 'sound' [Smith,P] |
| 10086 | Soundness is true axioms and a truth-preserving proof system [Smith,P] |
| 10596 | A theory is 'sound' iff every theorem is true (usually from true axioms and truth-preservation) [Smith,P] |
| 10598 | A theory is 'negation complete' if it proves all sentences or their negation [Smith,P] |
| 10597 | 'Complete' applies both to whole logics, and to theories within them [Smith,P] |
| 10069 | A theory is 'negation complete' if one of its sentences or its negation can always be proved [Smith,P] |
| 10609 | Two routes to Incompleteness: semantics of sound/expressible, or syntax of consistency/proof [Smith,P] |
| 10087 | A theory is 'decidable' if all of its sentences could be mechanically proved [Smith,P] |
| 10088 | Any consistent, axiomatized, negation-complete formal theory is decidable [Smith,P] |
| 10080 | 'Effective' means simple, unintuitive, independent, controlled, dumb, and terminating [Smith,P] |
| 10081 | A set is 'enumerable' is all of its elements can result from a natural number function [Smith,P] |
| 10083 | A set is 'effectively enumerable' if a computer could eventually list every member [Smith,P] |
| 10084 | A finite set of finitely specifiable objects is always effectively enumerable (e.g. primes) [Smith,P] |
| 10085 | The set of ordered pairs of natural numbers <i,j> is effectively enumerable [Smith,P] |
| 10601 | The thorems of a nice arithmetic can be enumerated, but not the truths (so they're diffferent) [Smith,P] |
| 10600 | Being 'expressible' depends on language; being 'capture/represented' depends on axioms and proof system [Smith,P] |
| 10599 | For primes we write (x not= 1 ∧ ∀u∀v(u x v = x → (u = 1 ∨ v = 1))) [Smith,P] |
| 10610 | The reals contain the naturals, but the theory of reals doesn't contain the theory of naturals [Smith,P] |
| 10619 | The truths of arithmetic are just true equations and their universally quantified versions [Smith,P] |
| 10618 | All numbers are related to zero by the ancestral of the successor relation [Smith,P] |
| 10608 | The number of Fs is the 'successor' of the Gs if there is a single F that isn't G [Smith,P] |
| 10849 | Baby arithmetic covers addition and multiplication, but no general facts about numbers [Smith,P] |
| 10850 | Baby Arithmetic is complete, but not very expressive [Smith,P] |
| 10851 | Robinson Arithmetic 'Q' has basic axioms, quantifiers and first-order logic [Smith,P] |
| 10852 | Robinson Arithmetic (Q) is not negation complete [Smith,P] |
| 10068 | Natural numbers have zero, unique successors, unending, no circling back, and no strays [Smith,P] |
| 10603 | The logic of arithmetic must quantify over properties of numbers to handle induction [Smith,P] |
| 10604 | Incompleteness results in arithmetic from combining addition and successor with multiplication [Smith,P] |
| 10848 | Multiplication only generates incompleteness if combined with addition and successor [Smith,P] |
| 14874 | Anaximander saw the contradiction in the world - that its own qualities destroy it [Anaximander, by Nietzsche] |
| 10617 | The 'ancestral' of a relation is a new relation which creates a long chain of the original relation [Smith,P] |
| 23957 | We often trust our intuitions as rational, despite their lack of reflection [Solomon] |
| 23943 | Distinguishing reason from passion is based on an archaic 'faculty' theory [Solomon] |
| 23952 | I say bodily chemistry and its sensations have nothing to do with emotions [Solomon] |
| 23954 | Emotions are judgements about ourselves, and our place in the world [Solomon] |
| 23961 | The heart of an emotion is its judgement of values and morality [Solomon] |
| 23960 | Emotions are defined by their objects [Solomon] |
| 23965 | Emotions can be analysed under fifteen headings [Solomon] |
| 23959 | Some emotions are externally directed, others internally [Solomon] |
| 23946 | The passions are subjective, concerning what is important to me, rather than facts [Solomon] |
| 23940 | Emotions are strategies for maximising our sense of dignity and self-esteem [Solomon] |
| 23949 | Passions exist as emotions, moods and desires, which all generate meaning [Solomon] |
| 23956 | The Myth of the Passions says they are irrational, uncontrolled and damaging [Solomon] |
| 23963 | Which emotions we feel depends on our sense of our own powers [Solomon] |
| 23936 | It is only our passions which give our lives meaning [Solomon] |
| 23953 | Feeling is a superficial aspect of emotion, and may be indeterminate, or even absent [Solomon] |
| 23964 | There are no 'basic' emotions, only socially prevalent ones [Solomon] |
| 23937 | It is reason which needs the anchorage of passions, rather than vice versa [Solomon] |
| 23947 | Dividing ourselves into confrontational reason and passion destroys our harmonious whole [Solomon] |
| 23958 | The supposed irrationality of our emotions is often tactless or faulty expression of them [Solomon] |
| 23944 | Emotions are our life force, and the source of most of our values [Solomon] |
| 23962 | Lovers adopt the interests of their beloved, rather than just valuing them [Solomon] |
| 23941 | 'Absurdity' is just the result of our wrong choices in life [Solomon] |
| 23955 | Ideologies are mythologies which guide our actions [Solomon] |
| 13222 | The Boundless cannot exist on its own, and must have something contrary to it [Aristotle on Anaximander] |
| 1495 | Anaximander introduced the idea that the first principle and element of things was the Boundless [Anaximander, by Simplicius] |
| 404 | Things begin and end in the Unlimited, and are balanced over time according to justice [Anaximander] |
| 405 | The essential nature, whatever it is, of the non-limited is everlasting and ageless [Anaximander] |
| 1746 | The parts of all things are susceptible to change, but the whole is unchangeable [Anaximander, by Diog. Laertius] |