18 ideas
| 343 | The unexamined life is not worth living for men [Socrates] |
| 14249 | Boolos reinterprets second-order logic as plural logic [Boolos, by Oliver/Smiley] |
| 10830 | Second-order logic metatheory is set-theoretic, and second-order validity has set-theoretic problems [Boolos] |
| 10829 | A sentence can't be a truth of logic if it asserts the existence of certain sets [Boolos] |
| 10832 | '∀x x=x' only means 'everything is identical to itself' if the range of 'everything' is fixed [Boolos] |
| 10834 | Weak completeness: if it is valid, it is provable. Strong: it is provable from a set of sentences [Boolos] |
| 13841 | Why should compactness be definitive of logic? [Boolos, by Hacking] |
| 10833 | Many concepts can only be expressed by second-order logic [Boolos] |
| 339 | Men fear death as a great evil when it may be a great blessing [Socrates] |
| 344 | If death is like a night of dreamless sleep, such nights are very pleasant [Socrates] |
| 2 | We should not even harm someone who harms us [Socrates] |
| 345 | A good man cannot be harmed, either in life or in death [Socrates] |
| 346 | One ought not to return a wrong or injury to any person, whatever the provocation [Socrates] |
| 341 | Wealth is good if it is accompanied by virtue [Socrates] |
| 347 | Will I stand up against the law, simply because I have been unjustly judged? [Socrates] |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| 338 | Socrates is accused of denying the gods, saying sun is stone and moon is earth [Socrates, by Plato] |