58 ideas
6675 | The heart has its reasons of which reason knows nothing [Pascal] |
17749 | Post proved the consistency of propositional logic in 1921 [Walicki] |
17765 | Propositional language can only relate statements as the same or as different [Walicki] |
17764 | Boolean connectives are interpreted as functions on the set {1,0} [Walicki] |
17752 | The empty set is useful for defining sets by properties, when the members are not yet known [Walicki] |
17753 | The empty set avoids having to take special precautions in case members vanish [Walicki] |
17759 | Ordinals play the central role in set theory, providing the model of well-ordering [Walicki] |
17741 | To determine the patterns in logic, one must identify its 'building blocks' [Walicki] |
10121 | Contradiction is not a sign of falsity, nor lack of contradiction a sign of truth [Pascal] |
17747 | A 'model' of a theory specifies interpreting a language in a domain to make all theorems true [Walicki] |
17748 | The L-S Theorem says no theory (even of reals) says more than a natural number theory [Walicki] |
17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [Walicki] |
17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
17757 | Members of ordinals are ordinals, and also subsets of ordinals [Walicki] |
17758 | Ordinals are transitive sets of transitive sets; or transitive sets totally ordered by inclusion [Walicki] |
17755 | Ordinals are the empty set, union with the singleton, and any arbitrary union of ordinals [Walicki] |
17756 | The union of finite ordinals is the first 'limit ordinal'; 2ω is the second... [Walicki] |
17760 | Two infinite ordinals can represent a single infinite cardinal [Walicki] |
17762 | In non-Euclidean geometry, all Euclidean theorems are valid that avoid the fifth postulate [Walicki] |
17754 | Inductive proof depends on the choice of the ordering [Walicki] |
16661 | There are two sorts of category - referring to things, and to circumstances of things [Boethius] |
15035 | If universals are not separate, we can isolate them by abstraction [Boethius, by Panaccio] |
14665 | We can call the quality of Plato 'Platonity', and say it is a quality which only he possesses [Boethius] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
23308 | Reasoning relates to understanding as time does to eternity [Boethius, by Sorabji] |
22011 | The first principles of truth are not rational, but are known by the heart [Pascal] |
5771 | Knowledge of present events doesn't make them necessary, so future events are no different [Boethius] |
5767 | Rational natures require free will, in order to have power of judgement [Boethius] |
5769 | Does foreknowledge cause necessity, or necessity cause foreknowledge? [Boethius] |
5768 | God's universal foreknowledge seems opposed to free will [Boethius] |
6681 | We only want to know things so that we can talk about them [Pascal] |
5762 | The wicked want goodness, so they would not be wicked if they obtained it [Boethius] |
6676 | Painting makes us admire things of which we do not admire the originals [Pascal] |
5770 | Rewards and punishments are not deserved if they don't arise from free movement of the mind [Boethius] |
5764 | When people fall into wickedness they lose their human nature [Boethius] |
6680 | It is a funny sort of justice whose limits are marked by a river [Pascal] |
6677 | Imagination creates beauty, justice and happiness, which is the supreme good [Pascal] |
5756 | Happiness is a good which once obtained leaves nothing more to be desired [Boethius] |
6678 | We live for the past or future, and so are never happy in the present [Pascal] |
5763 | The bad seek the good through desire, but the good through virtue, which is more natural [Boethius] |
5759 | Varied aims cannot be good because they differ, but only become good when they unify [Boethius] |
20732 | If man considers himself as lost and imprisoned in the universe, he will be terrified [Pascal] |
6682 | Majority opinion is visible and authoritative, although not very clever [Pascal] |
5754 | You can't control someone's free mind, only their body and possessions [Boethius] |
6679 | It is not good to be too free [Pascal] |
16692 | Divine eternity is the all-at-once and complete possession of unending life [Boethius] |
5752 | Where does evil come from if there is a god; where does good come from if there isn't? [Boethius] |
5757 | God is the supreme good, so no source of goodness could take precedence over God [Boethius] |
5758 | God is the good [Boethius] |
7457 | Pascal is right, but relies on the unsupported claim of a half as the chance of God's existence [Hacking on Pascal] |
7455 | Pascal knows you can't force belief, but you can make it much more probable [Pascal, by Hacking] |
7456 | The libertine would lose a life of enjoyable sin if he chose the cloisters [Hacking on Pascal] |
6684 | If you win the wager on God's existence you win everything, if you lose you lose nothing [Pascal] |
5760 | The power through which creation remains in existence and motion I call 'God' [Boethius] |
5753 | The regular events of this life could never be due to chance [Boethius] |
5765 | The reward of the good is to become gods [Boethius] |
5761 | God can do anything, but he cannot do evil, so evil must be nothing [Boethius] |
5766 | If you could see the plan of Providence, you would not think there was evil anywhere [Boethius] |