7 ideas
19404 | Necessities rest on contradiction, and contingencies on sufficient reason [Leibniz] |
13831 | Logic is based on transitions between sentences [Prawitz] |
13825 | Natural deduction introduction rules may represent 'definitions' of logical connectives [Prawitz] |
13823 | In natural deduction, inferences are atomic steps involving just one logical constant [Prawitz] |
1748 | Archelaus was the first person to say that the universe is boundless [Archelaus, by Diog. Laertius] |
19403 | Each of the infinite possible worlds has its own laws, and the individuals contain those laws [Leibniz] |
5989 | Archelaus said life began in a primeval slime [Archelaus, by Schofield] |