11 ideas
14970 | Normal system K has five axioms and rules [Cresswell] |
14971 | D is valid on every serial frame, but not where there are dead ends [Cresswell] |
14972 | S4 has 14 modalities, and always reduces to a maximum of three modal operators [Cresswell] |
14973 | In S5 all the long complex modalities reduce to just three, and their negations [Cresswell] |
14976 | Reject the Barcan if quantifiers are confined to worlds, and different things exist in other worlds [Cresswell] |
10304 | Very few things in set theory remain valid in intuitionist mathematics [Bernays] |
10303 | Restricted Platonism is just an ideal projection of a domain of thought [Bernays] |
10306 | Mathematical abstraction just goes in a different direction from logic [Bernays] |
14974 | A relation is 'Euclidean' if aRb and aRc imply bRc [Cresswell] |
14975 | A de dicto necessity is true in all worlds, but not necessarily of the same thing in each world [Cresswell] |
7417 | God can't have silly perfections, but how do we decide which ones are 'silly'? [Joslin] |