23 ideas
20320 | Truth is what unites, and the profound truths create a community [Jaspers] |
10757 | Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg] |
10751 | Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg] |
10759 | There are at least seven possible systems of semantics for second-order logic [Rossberg] |
10753 | Logical consequence is intuitively semantic, and captured by model theory [Rossberg] |
10752 | Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg] |
10754 | In proof-theory, logical form is shown by the logical constants [Rossberg] |
10756 | A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg] |
10758 | If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg] |
10761 | Completeness can always be achieved by cunning model-design [Rossberg] |
10755 | A deductive system is only incomplete with respect to a formal semantics [Rossberg] |
20323 | Freedom needs knowledge, the possibility of arbitrariness, and law [Jaspers] |
20322 | I am aware that freedom is possible, and the freedom is not in theory, but in seeking freedom [Jaspers] |
20324 | My freedom increases as I broaden my vision of possiblities and motives [Jaspers] |
20318 | My helplessness in philosophising reveals my being, and begins its upsurge [Jaspers] |
20321 | The struggle for Existenz is between people who are equals, and are utterly honest [Jaspers] |
20325 | Once we grasp freedom 'from' things, then freedom 'for' things becomes urgent [Jaspers] |
20315 | 'Existenz' is the potential being, which I could have, and ought to have [Jaspers] |
20317 | Mundane existence is general, falling under universals, but Existens is unique to individuals [Jaspers] |
20319 | We want the correct grasp on being that is neither solipsism nor absorption in the crowd [Jaspers] |
20316 | Every decision I make moves towards or away from fulfilled Existenz [Jaspers] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |