32 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] |
8195 | Undecidable statements result from quantifying over infinites, subjunctive conditionals, and the past tense [Dummett] |
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] |
8194 | Surely there is no exact single grain that brings a heap into existence [Dummett] |
8190 | Intuitionists rely on the proof of mathematical statements, not their truth [Dummett] |
18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
8198 | A 'Cambridge Change' is like saying 'the landscape changes as you travel east' [Dummett] |
8192 | I no longer think what a statement about the past says is just what can justify it [Dummett] |
8199 | The existence of a universe without sentience or intelligence is an unintelligible fantasy [Dummett] |
5163 | Basic propositions refer to a single experience, are incorrigible, and conclusively verifiable [Ayer] |
5167 | The argument from analogy fails, so the best account of other minds is behaviouristic [Ayer] |
5164 | A statement is meaningful if observation statements can be deduced from it [Ayer] |
8193 | Verification is not an individual but a collective activity [Dummett] |
5165 | Directly verifiable statements must entail at least one new observation statement [Ayer] |
5166 | The principle of verification is not an empirical hypothesis, but a definition [Ayer] |
18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
8189 | Truth-condition theorists must argue use can only be described by appeal to conditions of truth [Dummett] |
8191 | The truth-conditions theory must get agreement on a conception of truth [Dummett] |
5162 | Sentences only express propositions if they are meaningful; otherwise they are 'statements' [Ayer] |
5168 | Moral approval and disapproval concerns classes of actions, rather than particular actions [Ayer] |
8197 | Maybe past (which affects us) and future (which we can affect) are both real [Dummett] |
8196 | The present cannot exist alone as a mere boundary; past and future truths are rendered meaningless [Dummett] |