21 ideas
18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
18789 | Intuitionist logic looks best as natural deduction [Mares] |
18790 | Intuitionism as natural deduction has no rule for negation [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] |
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] |
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] |
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] |
10938 | The extremes of essentialism are that all properties are essential, or only very trivial ones [Rami] |
10940 | An 'individual essence' is possessed uniquely by a particular object [Rami] |
10939 | 'Sortal essentialism' says being a particular kind is what is essential [Rami] |
10934 | Unlosable properties are not the same as essential properties [Rami] |
10933 | Physical possibility is part of metaphysical possibility which is part of logical possibility [Rami] |
10932 | If it is possible 'for all I know' then it is 'epistemically possible' [Rami] |
18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
1497 | For Anaximenes nature is air, which takes different forms by rarefaction and condensation [Anaximenes, by Simplicius] |