13 ideas
| 8083 | Boole applied normal algebra to logic, aiming at an algebra of thought [Boole, by Devlin] |
| 7727 | Boole's notation can represent syllogisms and propositional arguments, but not both at once [Boole, by Weiner] |
| 9406 | A class is natural when everybody can spot further members of it [Quinton] |
| 8686 | Boole made logic more mathematical, with algebra, quantifiers and probability [Boole, by Friend] |
| 22277 | Boole's method was axiomatic, achieving economy, plus multiple interpretations [Boole, by Potter] |
| 15730 | Extreme nominalists say all classification is arbitrary convention [Quinton] |
| 15728 | The naturalness of a class depends as much on the observers as on the objects [Quinton] |
| 9407 | Properties imply natural classes which can be picked out by everybody [Quinton] |
| 15729 | Uninstantiated properties must be defined using the instantiated ones [Quinton] |
| 8520 | An individual is a union of a group of qualities and a position [Quinton, by Campbell,K] |
| 335 | Do the gods also hold different opinions about what is right and honourable? [Plato] |
| 336 | Is what is pious loved by the gods because it is pious, or is it pious because they love it? (the 'Euthyphro Question') [Plato] |
| 337 | It seems that the gods love things because they are pious, rather than making them pious by loving them [Plato] |