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] |
12697 | Indivisibles are not parts, but the extrema of parts [Leibniz] |
490 | Everything happens by reason and necessity [Leucippus] |