19 ideas
15527 | Defining terms either enables elimination, or shows that they don't require elimination [Lewis] |
11211 | If a sound conclusion comes from two errors that cancel out, the path of the argument must matter [Rumfitt] |
18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
11212 | The sense of a connective comes from primitively obvious rules of inference [Rumfitt] |
11210 | Standardly 'and' and 'but' are held to have the same sense by having the same truth table [Rumfitt] |
18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
18745 | A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew] |
18747 | The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew] |
18748 | Epistemic logic introduced impossible worlds [Horsten/Pettigrew] |
18746 | Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew] |
18750 | Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew] |
15530 | A logically determinate name names the same thing in every possible world [Lewis] |
15531 | The Ramsey sentence of a theory says that it has at least one realisation [Lewis] |
15528 | A Ramsey sentence just asserts that a theory can be realised, without saying by what [Lewis] |
15526 | There is a method for defining new scientific terms just using the terms we already understand [Lewis] |
15529 | It is better to have one realisation of a theory than many - but it may not always be possible [Lewis] |
11214 | We learn 'not' along with affirmation, by learning to either affirm or deny a sentence [Rumfitt] |