69 ideas
| 6851 | We overvalue whether arguments are valid, and undervalue whether they are interesting [Monk] |
| 15477 | Ontology is highly abstract physics, containing placeholders and exclusions [Martin,CB] |
| 15471 | Truth is a relation between a representation ('bearer') and part of the world ('truthmaker') [Martin,CB] |
| 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] |
| 13201 | ∈ says the whole set is in the other; ⊆ says the members of the subset are in the other [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] |
| 13204 | The 'ordered pair' <x,y> is defined to be {{x}, {x,y}} [Enderton] |
| 13206 | A 'linear or total ordering' must be transitive and satisfy trichotomy [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] |
| 13200 | Note that {Φ} =/= Φ, because Φ ∈ {Φ} but Φ ∉ Φ [Enderton] |
| 13199 | The empty set may look pointless, but many sets can be constructed from it [Enderton] |
| 13203 | The singleton is defined using the pairing axiom (as {x,x}) [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] |
| 13202 | Fraenkel added Replacement, to give a theory of ordinal numbers [Enderton] |
| 13205 | We can only define functions if Choice tells us which items are involved [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] |
| 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] |
| 15484 | A property is a combination of a disposition and a quality [Martin,CB] |
| 15478 | Properties are the respects in which objects resemble, which places them in classes [Martin,CB] |
| 15483 | Properties are ways particular things are, and so they are tied to the identity of their possessor [Martin,CB] |
| 15480 | Objects are not bundles of tropes (which are ways things are, not parts of things) [Martin,CB] |
| 15489 | A property that cannot interact is worse than inert - it isn't there at all [Martin,CB] |
| 15487 | If unmanifested partnerless dispositions are still real, and are not just qualities, they can explain properties [Martin,CB] |
| 15479 | Properties endow a ball with qualities, and with powers or dispositions [Martin,CB] |
| 15488 | Qualities and dispositions are aspects of properties - what it exhibits, and what it does [Martin,CB] |
| 15469 | Dispositions in action can be destroyed, be recovered, or remain unchanged [Martin,CB] |
| 15467 | Powers depend on circumstances, so can't be given a conditional analysis [Martin,CB] |
| 15466 | 'The wire is live' can't be analysed as a conditional, because a wire can change its powers [Martin,CB] |
| 15476 | Structural properties involve dispositionality, so cannot be used to explain it [Martin,CB] |
| 15465 | Structures don't explain dispositions, because they consist of dispositions [Martin,CB] |
| 15481 | I favour the idea of a substratum for properties; spacetime seems to be just a bearer of properties [Martin,CB] |
| 15474 | Properly understood, wholes do no more causal work than their parts [Martin,CB] |
| 15486 | Only abstract things can have specific and full identity specifications [Martin,CB] |
| 15475 | The concept of 'identity' must allow for some changes in properties or parts [Martin,CB] |
| 9723 | Sentences with 'if' are only conditionals if they can read as A-implies-B [Enderton] |
| 15472 | It is pointless to say possible worlds are truthmakers, and then deny that possible worlds exist [Martin,CB] |
| 15492 | Explanations are mind-dependent, theory-laden, and interest-relative [Martin,CB] |
| 15495 | Analogy works, as when we eat food which others seem to be relishing [Martin,CB] |
| 15493 | Memory requires abstraction, as reminders of what cannot be fully remembered [Martin,CB] |
| 7535 | If all beliefs are propositional, then belief and judgement are the same thing [Monk] |
| 6850 | Wittgenstein pared his life down in his search for decency [Monk] |
| 15485 | Instead of a cause followed by an effect, we have dispositions in reciprocal manifestation [Martin,CB] |
| 15491 | Causation should be explained in terms of dispositions and manifestations [Martin,CB] |
| 15468 | Causal counterfactuals are just clumsy linguistic attempts to indicate dispositions [Martin,CB] |
| 15470 | Causal laws are summaries of powers [Martin,CB] |
| 15482 | We can't think of space-time as empty and propertyless, and it seems to be a substratum [Martin,CB] |