52 ideas
| 2956 | There is nothing so obvious that a philosopher cannot be found to deny it [Lockwood] |
| 2963 | There may only be necessary and sufficient conditions (and counterfactuals) because we intervene in the world [Lockwood] |
| 2958 | No one has ever succeeded in producing an acceptable non-trivial analysis of anything [Lockwood] |
| 2959 | If something is described in two different ways, is that two facts, or one fact presented in two ways? [Lockwood] |
| 9724 | Until the 1960s the only semantics was truth-tables [Enderton] |
| 9703 | 'dom R' indicates the 'domain' of objects having a relation [Enderton] |
| 9705 | 'fld R' indicates the 'field' of all objects in the relation [Enderton] |
| 9704 | 'ran R' indicates the 'range' of objects being related to [Enderton] |
| 9710 | We write F:A→B to indicate that A maps into B (the output of F on A is in B) [Enderton] |
| 9707 | 'F(x)' is the unique value which F assumes for a value of x [Enderton] |
| 9712 | A relation is 'symmetric' on a set if every ordered pair has the relation in both directions [Enderton] |
| 9713 | A relation is 'transitive' if it can be carried over from two ordered pairs to a third [Enderton] |
| 9699 | The 'powerset' of a set is all the subsets of a given set [Enderton] |
| 9700 | Two sets are 'disjoint' iff their intersection is empty [Enderton] |
| 9702 | A 'domain' of a relation is the set of members of ordered pairs in the relation [Enderton] |
| 9701 | A 'relation' is a set of ordered pairs [Enderton] |
| 9706 | A 'function' is a relation in which each object is related to just one other object [Enderton] |
| 9708 | A function 'maps A into B' if the relating things are set A, and the things related to are all in B [Enderton] |
| 9709 | A function 'maps A onto B' if the relating things are set A, and the things related to are set B [Enderton] |
| 9711 | A relation is 'reflexive' on a set if every member bears the relation to itself [Enderton] |
| 9714 | A relation satisfies 'trichotomy' if all pairs are either relations, or contain identical objects [Enderton] |
| 9717 | A set is 'dominated' by another if a one-to-one function maps the first set into a subset of the second [Enderton] |
| 9715 | An 'equivalence relation' is a reflexive, symmetric and transitive binary relation [Enderton] |
| 9716 | We 'partition' a set into distinct subsets, according to each relation on its objects [Enderton] |
| 9722 | Inference not from content, but from the fact that it was said, is 'conversational implicature' [Enderton] |
| 9718 | Validity is either semantic (what preserves truth), or proof-theoretic (following procedures) [Enderton] |
| 16974 | The nature of each logical concept is given by a collection of inference rules [Correia] |
| 9721 | A logical truth or tautology is a logical consequence of the empty set [Enderton] |
| 9994 | A truth assignment to the components of a wff 'satisfy' it if the wff is then True [Enderton] |
| 9719 | A proof theory is 'sound' if its valid inferences entail semantic validity [Enderton] |
| 9720 | A proof theory is 'complete' if semantically valid inferences entail proof-theoretic validity [Enderton] |
| 9995 | Proof in finite subsets is sufficient for proof in an infinite set [Enderton] |
| 9996 | Expressions are 'decidable' if inclusion in them (or not) can be proved [Enderton] |
| 9997 | For a reasonable language, the set of valid wff's can always be enumerated [Enderton] |
| 2969 | How does a direct realist distinguish a building from Buckingham Palace? [Lockwood] |
| 16973 | Explain logical necessity by logical consequence, or the other way around? [Correia] |
| 9723 | Sentences with 'if' are only conditionals if they can read as A-implies-B [Enderton] |
| 2970 | Dogs seem to have beliefs, and beliefs require concepts [Lockwood] |
| 2961 | Empiricism is a theory of meaning as well as of knowledge [Lockwood] |
| 2960 | Commonsense realism must account for the similarity of genuine perceptions and known illusions [Lockwood] |
| 2952 | A 1988 estimate gave the brain 3 x 10-to-the-14 synaptic junctions [Lockwood] |
| 2964 | How come unconscious states also cause behaviour? [Lockwood] |
| 2951 | Could there be unconscious beliefs and desires? [Lockwood] |
| 2953 | Fish may operate by blindsight [Lockwood] |
| 2967 | We might even learn some fundamental physics from introspection [Lockwood] |
| 2966 | Can phenomenal qualities exist unsensed? [Lockwood] |
| 2955 | If mental events occur in time, then relativity says they are in space [Lockwood] |
| 2950 | Only logical positivists ever believed behaviourism [Lockwood] |
| 2954 | Identity theory likes the identity of lightning and electrical discharges [Lockwood] |
| 2971 | Perhaps logical positivism showed that there is no dividing line between science and metaphysics [Lockwood] |
| 2962 | Maybe causation is a form of rational explanation, not an observation or a state of mind [Lockwood] |
| 2949 | We have the confused idea that time is a process of change [Lockwood] |