8 ideas
10163 | Propositional modal logic has been proved to be complete [Kripke, by Feferman/Feferman] |
10760 | With possible worlds, S4 and S5 are sound and complete, but S1-S3 are not even sound [Kripke, by Rossberg] |
16189 | The variable domain approach to quantified modal logic invalidates the Barcan Formula [Kripke, by Simchen] |
15132 | The Barcan formulas fail in models with varying domains [Kripke, by Williamson] |
16736 | Explanation is generally to deduce it from something better known, which comes in degrees [Boyle] |
16737 | The best explanations get down to primary basics, but others go less deep [Boyle] |
1474 | Moral evil may be acceptable to God because it allows free will (even though we don't see why this is necessary) [Plantinga, by PG] |
1475 | It is logically possible that natural evil like earthquakes is caused by Satan [Plantinga, by PG] |