4 ideas
13342 | Carnap defined consequence by contradiction, but this is unintuitive and changes with substitution [Tarski on Carnap] |
13251 | Each person is free to build their own logic, just by specifying a syntax [Carnap] |
22456 | Maybe virtues conflict with each other, if some virtue needs a vice for its achievement [Foot] |
651 | Eurytus showed that numbers underlie things by making pictures of creatures out of pebbles [Eurytus, by Aristotle] |