27 ideas
18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
18789 | Intuitionist logic looks best as natural deduction [Mares] |
18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
18782 | The connectives are studied either through model theory or through proof theory [Mares] |
18783 | Many-valued logics lack a natural deduction system [Mares] |
18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
12699 | A body would be endless disunited parts, if it did not have a unifying form or soul [Leibniz] |
12700 | Form or soul gives unity and duration; matter gives multiplicity and change [Leibniz] |
12736 | If we understand God and his choices, we have a priori knowledge of contingent truths [Leibniz, by Garber] |
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] |
12698 | Every body contains a kind of sense and appetite, or a soul [Leibniz] |
18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |