36 ideas
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] |
16065 | Constitution is identity (being in the same place), or it isn't (having different possibilities) [Wasserman] |
16067 | Constitution is not identity, because it is an asymmetric dependence relation [Wasserman] |
16069 | There are three main objections to seeing constitution as different from identity [Wasserman] |
16068 | The weight of a wall is not the weight of its parts, since that would involve double-counting [Wasserman] |
16074 | Relative identity may reject transitivity, but that suggests that it isn't about 'identity' [Wasserman] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
7352 | Jesus said learning was unnecessary, and only the spirit of the Law was needed [Jesus, by Johnson,P] |
6289 | Love your enemies [Jesus] |
6292 | Love thy neighbour as thyself [Jesus] |
5356 | Treat others as you would have them treat you [Jesus] |
6286 | Blessed are the merciful: for they shall obtain mercy [Jesus] |
6290 | Except ye become as little children, ye shall not enter heaven [Jesus] |
6287 | If you lust after a woman, you have committed adultery [Jesus] |
6285 | Blessed are the meek; for they shall inherit the earth [Jesus] |
6288 | Don't resist evil, but turn the other cheek [Jesus] |
6293 | It is almost impossible for the rich to go to heaven [Jesus] |
6291 | No one is good except God [Jesus] |
7351 | Jesus turned the ideas of Hillel into a theology reduced to its moral elements [Jesus, by Johnson,P] |