43 ideas
| 19695 | The devil was wise as an angel, and lost no knowledge when he rebelled [Whitcomb] |
| 10308 | Questions about objects are questions about certain non-vacuous singular terms [Hale] |
| 10314 | An expression is a genuine singular term if it resists elimination by paraphrase [Hale] |
| 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] |
| 10316 | We should decide whether singular terms are genuine by their usage [Hale] |
| 10312 | Often the same singular term does not ensure reliable inference [Hale] |
| 10313 | Plenty of clear examples have singular terms with no ontological commitment [Hale] |
| 10322 | If singular terms can't be language-neutral, then we face a relativity about their objects [Hale] |
| 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] |
| 13531 | Model theory reveals the structures of mathematics [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] |
| 10512 | The abstract/concrete distinction is based on what is perceivable, causal and located [Hale] |
| 10517 | Colours and points seem to be both concrete and abstract [Hale] |
| 10519 | The abstract/concrete distinction is in the relations in the identity-criteria of object-names [Hale] |
| 10520 | Token-letters and token-words are concrete objects, type-letters and type-words abstract [Hale] |
| 10524 | There is a hierarchy of abstraction, based on steps taken by equivalence relations [Hale] |
| 10521 | If F can't have location, there is no problem of things having F in different locations [Hale] |
| 10511 | It is doubtful if one entity, a universal, can be picked out by both predicates and abstract nouns [Hale] |
| 10318 | Realists take universals to be the referrents of both adjectives and of nouns [Hale] |
| 10310 | Objections to Frege: abstracta are unknowable, non-independent, unstatable, unindividuated [Hale] |
| 10518 | Shapes and directions are of something, but games and musical compositions are not [Hale] |
| 10513 | Many abstract objects, such as chess, seem non-spatial, but are not atemporal [Hale] |
| 10514 | If the mental is non-spatial but temporal, then it must be classified as abstract [Hale] |
| 10523 | Being abstract is based on a relation between things which are spatially separated [Hale] |
| 10307 | The modern Fregean use of the term 'object' is much broader than the ordinary usage [Hale] |
| 10315 | We can't believe in a 'whereabouts' because we ask 'what kind of object is it?' [Hale] |
| 10522 | The relations featured in criteria of identity are always equivalence relations [Hale] |
| 10321 | We sometimes apply identity without having a real criterion [Hale] |