49 ideas
| 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] |
| 13520 | A 'tautology' must include connectives [Wolf,RS] |
| 13524 | Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS] |
| 13522 | Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [Wolf,RS] |
| 13521 | Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS] |
| 13523 | Existential Generalization (or 'proof by example'): if we can say P(t), then we can say something is P [Wolf,RS] |
| 13529 | Empty Set: ∃x∀y ¬(y∈x). The unique empty set exists [Wolf,RS] |
| 13526 | Comprehension Axiom: if a collection is clearly specified, it is a set [Wolf,RS] |
| 13534 | In first-order logic syntactic and semantic consequence (|- and |=) nicely coincide [Wolf,RS] |
| 13535 | First-order logic is weakly complete (valid sentences are provable); we can't prove every sentence or its negation [Wolf,RS] |
| 13531 | Model theory reveals the structures of mathematics [Wolf,RS] |
| 13532 | Model theory 'structures' have a 'universe', some 'relations', some 'functions', and some 'constants' [Wolf,RS] |
| 13519 | Model theory uses sets to show that mathematical deduction fits mathematical truth [Wolf,RS] |
| 13533 | First-order model theory rests on completeness, compactness, and the Löwenheim-Skolem-Tarski theorem [Wolf,RS] |
| 13537 | An 'isomorphism' is a bijection that preserves all structural components [Wolf,RS] |
| 13539 | The LST Theorem is a serious limitation of first-order logic [Wolf,RS] |
| 13538 | If a theory is complete, only a more powerful language can strengthen it [Wolf,RS] |
| 13525 | Most deductive logic (unlike ordinary reasoning) is 'monotonic' - we don't retract after new givens [Wolf,RS] |
| 13530 | An ordinal is an equivalence class of well-orderings, or a transitive set whose members are transitive [Wolf,RS] |
| 13518 | Modern mathematics has unified all of its objects within set theory [Wolf,RS] |
| 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] |
| 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] |
| 22745 | Pherecydes said the first principle and element is earth [Pherecydes, by Sext.Empiricus] |
| 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] |
| 5883 | Pherecydes was the first to say that the soul is eternal [Pherecydes, by Cicero] |