20 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] |
15375 | If terms change their designations in different states, they are functions from states to objects [Fitting] |
15376 | Intensional logic adds a second type of quantification, over intensional objects, or individual concepts [Fitting] |
15378 | Awareness logic adds the restriction of an awareness function to epistemic logic [Fitting] |
15379 | Justication logics make explicit the reasons for mathematical truth in proofs [Fitting] |
11026 | Classical logic is deliberately extensional, in order to model mathematics [Fitting] |
11028 | λ-abstraction disambiguates the scope of modal operators [Fitting] |
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] |
15377 | Definite descriptions pick out different objects in different possible worlds [Fitting] |
17065 | 2: An explanation must wholly cohere internally, and with the new fact [Thagard, by Smart] |
17066 | 3: If an analogous pair explain another analogous pair, then they all cohere [Thagard, by Smart] |
17064 | 1: Coherence is a symmetrical relation between two propositions [Thagard, by Smart] |
17067 | 4: For coherence, observation reports have a degree of intrinsic acceptability [Thagard, by Smart] |
17068 | 5: Contradictory propositions incohere [Thagard, by Smart] |
17069 | 6: A proposition's acceptability depends on its coherence with a system [Thagard, by Smart] |