68 ideas
| 18835 | Logic doesn't have a metaphysical basis, but nor can logic give rise to the metaphysics [Rumfitt] |
| 6887 | Linguistic philosophy approaches problems by attending to actual linguistic usage [Mautner] |
| 6881 | Analytic philosophy studies the unimportant, and sharpens tools instead of using them [Mautner] |
| 5439 | The 'hermeneutic circle' says parts and wholes are interdependent, and so cannot be interpreted [Mautner] |
| 9959 | 'Real' definitions give the essential properties of things under a concept [Mautner] |
| 9961 | 'Contextual definitions' replace whole statements, not just expressions [Mautner] |
| 9958 | Recursive definition defines each instance from a previous instance [Mautner] |
| 9960 | A stipulative definition lays down that an expression is to have a certain meaning [Mautner] |
| 9957 | Ostensive definitions point to an object which an expression denotes [Mautner] |
| 6219 | The fallacy of composition is the assumption that what is true of the parts is true of the whole [Mautner] |
| 18819 | The idea that there are unrecognised truths is basic to our concept of truth [Rumfitt] |
| 18826 | 'True at a possibility' means necessarily true if what is said had obtained [Rumfitt] |
| 18803 | Semantics for propositions: 1) validity preserves truth 2) non-contradition 3) bivalence 4) truth tables [Rumfitt] |
| 18814 | 'Absolute necessity' would have to rest on S5 [Rumfitt] |
| 18798 | It is the second-order part of intuitionistic logic which actually negates some classical theorems [Rumfitt] |
| 18799 | Intuitionists can accept Double Negation Elimination for decidable propositions [Rumfitt] |
| 6888 | Fuzzy logic is based on the notion that there can be membership of a set to some degree [Mautner] |
| 18830 | Most set theorists doubt bivalence for the Continuum Hypothesis, but still use classical logic [Rumfitt] |
| 18843 | The iterated conception of set requires continual increase in axiom strength [Rumfitt] |
| 18836 | A set may well not consist of its members; the empty set, for example, is a problem [Rumfitt] |
| 18837 | A set can be determinate, because of its concept, and still have vague membership [Rumfitt] |
| 18845 | If the totality of sets is not well-defined, there must be doubt about the Power Set Axiom [Rumfitt] |
| 18815 | Logic is higher-order laws which can expand the range of any sort of deduction [Rumfitt] |
| 18804 | The case for classical logic rests on its rules, much more than on the Principle of Bivalence [Rumfitt] |
| 18805 | Classical logic rules cannot be proved, but various lines of attack can be repelled [Rumfitt] |
| 18827 | If truth-tables specify the connectives, classical logic must rely on Bivalence [Rumfitt] |
| 18813 | Logical consequence is a relation that can extended into further statements [Rumfitt] |
| 18808 | Normal deduction presupposes the Cut Law [Rumfitt] |
| 6877 | Entailment is logical requirement; it may be not(p and not-q), but that has problems [Mautner] |
| 6880 | Strict implication says false propositions imply everything, and everything implies true propositions [Mautner] |
| 6879 | 'Material implication' is defined as 'not(p and not-q)', but seems to imply a connection between p and q [Mautner] |
| 6878 | A person who 'infers' draws the conclusion, but a person who 'implies' leaves it to the audience [Mautner] |
| 6889 | Vagueness seems to be inconsistent with the view that every proposition is true or false [Mautner] |
| 18840 | When faced with vague statements, Bivalence is not a compelling principle [Rumfitt] |
| 18802 | In specifying a logical constant, use of that constant is quite unavoidable [Rumfitt] |
| 6890 | Quantifiers turn an open sentence into one to which a truth-value can be assigned [Mautner] |
| 18800 | Introduction rules give deduction conditions, and Elimination says what can be deduced [Rumfitt] |
| 18809 | Logical truths are just the assumption-free by-products of logical rules [Rumfitt] |
| 18807 | Monotonicity means there is a guarantee, rather than mere inductive support [Rumfitt] |
| 18842 | Maybe an ordinal is a property of isomorphic well-ordered sets, and not itself a set [Rumfitt] |
| 18834 | Infinitesimals do not stand in a determinate order relation to zero [Rumfitt] |
| 18846 | Cantor and Dedekind aimed to give analysis a foundation in set theory (rather than geometry) [Rumfitt] |
| 18839 | An object that is not clearly red or orange can still be red-or-orange, which sweeps up problem cases [Rumfitt] |
| 18838 | The extension of a colour is decided by a concept's place in a network of contraries [Rumfitt] |
| 18816 | Metaphysical modalities respect the actual identities of things [Rumfitt] |
| 18825 | S5 is the logic of logical necessity [Rumfitt] |
| 18824 | Since possibilities are properties of the world, calling 'red' the determination of a determinable seems right [Rumfitt] |
| 18828 | If two possibilities can't share a determiner, they are incompatible [Rumfitt] |
| 6882 | Counterfactuals presuppose a belief (or a fact) that the condition is false [Mautner] |
| 6886 | Counterfactuals are not true, they are merely valid [Mautner] |
| 6885 | Counterfactuals are true if in every world close to actual where p is the case, q is also the case [Mautner] |
| 6884 | Counterfactuals say 'If it had been, or were, p, then it would be q' [Mautner] |
| 6883 | Maybe counterfactuals are only true if they contain valid inference from premisses [Mautner] |
| 5449 | Essentialism is often identified with belief in 'de re' necessary truths [Mautner] |
| 18821 | Possibilities are like possible worlds, but not fully determinate or complete [Rumfitt] |
| 18831 | Medieval logicians said understanding A also involved understanding not-A [Rumfitt] |
| 6898 | Fallibilism is the view that all knowledge-claims are provisional [Mautner] |
| 6452 | 'Sense-data' arrived in 1910, but it denotes ideas in Locke, Berkeley and Hume [Mautner] |
| 18820 | In English 'evidence' is a mass term, qualified by 'little' and 'more' [Rumfitt] |
| 4783 | Observing lots of green x can confirm 'all x are green' or 'all x are grue', where 'grue' is arbitrary [Mautner, by PG] |
| 4782 | 'All x are y' is equivalent to 'all non-y are non-x', so observing paper is white confirms 'ravens are black' [Mautner, by PG] |
| 18817 | We understand conditionals, but disagree over their truth-conditions [Rumfitt] |
| 6899 | The references of indexicals ('there', 'now', 'I') depend on the circumstances of utterance [Mautner] |
| 18829 | The truth grounds for 'not A' are the possibilities incompatible with truth grounds for A [Rumfitt] |
| 6896 | Double effect is the distinction between what is foreseen and what is intended [Mautner] |
| 6897 | Double effect acts need goodness, unintended evil, good not caused by evil, and outweighing [Mautner] |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| 5452 | 'Essentialism' is opposed to existentialism, and claims there is a human nature [Mautner] |