37 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] |
21812 | Being is the product of pure intellect [Plotinus] |
21817 | The One does not exist, but is the source of all existence [Plotinus] |
21824 | The One is a principle which transcends Being [Plotinus] |
21813 | Number determines individual being [Plotinus] |
17742 | Scotus based modality on semantic consistency, instead of on what the future could allow [Walicki] |
5506 | If soul was like body, its parts would be separate, without communication [Plotinus] |
21827 | The movement of Soul is continuous, but we are only aware of the parts of it that are sensed [Plotinus] |
21828 | A person is the whole of their soul [Plotinus] |
21809 | Our soul has the same ideal nature as the oldest god, and is honourable above the body [Plotinus] |
21825 | The soul is outside of all of space, and has no connection to the bodily order [Plotinus] |
21826 | The Soul reasons about the Right, so there must be some permanent Right about which it reasons [Plotinus] |
6922 | Ecstasy is for the neo-Platonist the highest psychological state of man [Plotinus, by Feuerbach] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
21816 | Soul is the logos of Nous, just as Nous is the logos of the One [Plotinus] |
21815 | Because the One is immobile, it must create by radiation, light the sun producing light [Plotinus] |
21814 | How can multiple existence arise from the unified One? [Plotinus] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |
21808 | Soul is author of all of life, and of the stars, and it gives them law and movement [Plotinus] |
21811 | Even the soul is secondary to the Intellectual-Principle [Nous], of which soul is an utterance [Plotinus] |