53 ideas
| 22309 | An idea can only be like another idea [Berkeley] |
| 13520 | A 'tautology' must include connectives [Wolf,RS] |
| 13524 | Deduction Theorem: T∪{P}|-Q, then T|-(P→Q), which justifies Conditional Proof [Wolf,RS] |
| 13521 | Universal Specification: ∀xP(x) implies P(t). True for all? Then true for an instance [Wolf,RS] |
| 13522 | Universal Generalization: If we prove P(x) with no special assumptions, we can conclude ∀xP(x) [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] |
| 13519 | Model theory uses sets to show that mathematical deduction fits mathematical truth [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] |
| 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] |
| 6717 | Abstract ideas are impossible [Berkeley] |
| 18876 | Berkeley does believe in trees, but is confused about what trees are [Berkeley, by Cameron] |
| 6715 | Universals do not have single meaning, but attach to many different particulars [Berkeley] |
| 6719 | No one will think of abstractions if they only have particular ideas [Berkeley] |
| 6714 | Universals do not have any intrinsic properties, but only relations to particulars [Berkeley] |
| 6729 | Material substance is just general existence which can have properties [Berkeley] |
| 16636 | A die has no distinct subject, but is merely a name for its modes or accidents [Berkeley] |
| 6722 | Perception is existence for my table, but also possible perception, by me or a spirit [Berkeley] |
| 6723 | The 'esse' of objects is 'percipi', and they can only exist in minds [Berkeley] |
| 6732 | When I shut my eyes, the things I saw may still exist, but in another mind [Berkeley] |
| 6724 | The only substance is spirit, or that which perceives [Berkeley] |
| 6726 | No one can, by abstraction, conceive extension and motion of bodies without sensible qualities [Berkeley] |
| 6728 | Motion is in the mind, since swifter ideas produce an appearance of slower motion [Berkeley] |
| 6727 | Figure and extension seem just as dependent on the observer as heat and cold [Berkeley] |
| 6495 | Berkeley's idealism resulted from fear of scepticism in representative realism [Robinson,H on Berkeley] |
| 6720 | Knowledge is of ideas from senses, or ideas of the mind, or operations on sensations [Berkeley] |
| 23636 | Berkeley's idealism gives no grounds for believing in other minds [Reid on Berkeley] |
| 6736 | I know other minds by ideas which are referred by me to other agents, as their effects [Berkeley] |
| 6713 | If animals have ideas, and are not machines, they must have some reason [Berkeley] |
| 6491 | Berkeley replaced intentionality with an anti-abstractionist imagist theory of thought [Berkeley, by Robinson,H] |
| 6711 | The mind creates abstract ideas by considering qualities separated from their objects [Berkeley] |
| 10581 | I can only combine particulars in imagination; I can't create 'abstract' ideas [Berkeley] |
| 6721 | Ideas are perceived by the mind, soul or self [Berkeley] |
| 6716 | Language is presumably for communication, and names stand for ideas [Berkeley] |
| 6718 | I can't really go wrong if I stick to wordless thought [Berkeley] |
| 7903 | The six perfections are giving, morality, patience, vigour, meditation, and wisdom [Nagarjuna] |
| 6731 | No one can explain how matter affects mind, so matter is redundant in philosophy [Berkeley] |
| 6730 | We discover natural behaviour by observing settled laws of nature, not necessary connections [Berkeley] |
| 15861 | The laws of nature are mental regularities which we learn by experience [Berkeley] |
| 6734 | If properties and qualities arise from an inward essence, we will remain ignorant of nature [Berkeley] |
| 6735 | All motion is relative, so a single body cannot move [Berkeley] |
| 6733 | I cannot imagine time apart from the flow of ideas in my mind [Berkeley] |
| 6737 | Particular evils are really good when linked to the whole system of beings [Berkeley] |