41 ideas
| 21959 | Metaphysics is the most general attempt to make sense of things [Moore,AW] |
| 2653 | If the parts of the universe are subject to the law of nature, the whole universe must also be subject to it [Cicero] |
| 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] |
| 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] |
| 17761 | A compact axiomatisation makes it possible to understand a field as a whole [Walicki] |
| 17763 | Axiomatic systems are purely syntactic, and do not presuppose any interpretation [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] |
| 17757 | Members of ordinals are ordinals, and also subsets of ordinals [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] |
| 17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
| 21958 | Appearances are nothing beyond representations, which is transcendental ideality [Moore,AW] |
| 2628 | Why would mind mix with matter if it didn't need it? [Cicero] |
| 20814 | Eloquence educates, exhorts, comforts, distracts and unites us, and raises us from savagery [Cicero] |
| 2640 | We have the death penalty, but still have thousands of robbers [Cicero] |
| 2652 | Some regard nature simply as an irrational force that imparts movement [Cicero] |
| 2645 | Why shouldn't the gods fear their own destruction? [Cicero] |
| 2627 | I wonder whether loss of reverence for the gods would mean the end of all virtue [Cicero] |
| 2651 | God doesn't obey the laws of nature; they are subject to the law of God [Cicero] |
| 2634 | It seems clear to me that we have an innate idea of the divine [Cicero] |
| 2636 | Many primitive people know nothing of the gods [Cicero] |
| 2647 | It is obvious from order that someone is in charge, as when we visit a gymnasium [Cicero] |
| 2650 | If a person cannot feel the power of God when looking at the stars, they are probably incapable of feeling [Cicero] |
| 2655 | If the barbarians of Britain saw a complex machine, they would be baffled, but would know it was designed [Cicero] |
| 2656 | Chance is no more likely to create the world than spilling lots of letters is likely to create a famous poem [Cicero] |
| 2657 | If everything with regular movement and order is divine, then recurrent illnesses must be divine [Cicero] |
| 2638 | Either the gods are identical, or one is more beautiful than another [Cicero] |
| 2635 | The gods are happy, so virtuous, so rational, so must have human shape [Cicero] |
| 2641 | Why believe in gods if you have never seen them? [Cicero] |
| 2659 | The lists of good men who have suffered and bad men who have prospered are endless [Cicero] |
| 2658 | The gods blame men for having vices, but they could have given us enough reason to avoid them [Cicero] |