66 ideas
23770 | Reductive analysis makes a concept clearer, by giving an alternative simpler set [Williams,NE] |
23769 | Promoting an ontology by its implied good metaphysic is an 'argument-by-display' [Williams,NE] |
15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
8729 | Intuitionists deny excluded middle, because it is committed to transcendent truth or objects [Shapiro] |
15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
15409 | All occurrences of variables in atomic formulas are free [Burgess] |
15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
15412 | Models leave out meaning, and just focus on truth values [Burgess] |
15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
8763 | The number 3 is presumably identical as a natural, an integer, a rational, a real, and complex [Shapiro] |
18249 | Cauchy gave a formal definition of a converging sequence. [Shapiro] |
8764 | Categories are the best foundation for mathematics [Shapiro] |
8762 | Two definitions of 3 in terms of sets disagree over whether 1 is a member of 3 [Shapiro] |
8760 | Numbers do not exist independently; the essence of a number is its relations to other numbers [Shapiro] |
8761 | A 'system' is related objects; a 'pattern' or 'structure' abstracts the pure relations from them [Shapiro] |
8744 | Logicism seems to be a non-starter if (as is widely held) logic has no ontology of its own [Shapiro] |
8749 | Term Formalism says mathematics is just about symbols - but real numbers have no names [Shapiro] |
8750 | Game Formalism is just a matter of rules, like chess - but then why is it useful in science? [Shapiro] |
8752 | Deductivism says mathematics is logical consequences of uninterpreted axioms [Shapiro] |
8753 | Critics resent the way intuitionism cripples mathematics, but it allows new important distinctions [Shapiro] |
8731 | Conceptualist are just realists or idealist or nominalists, depending on their view of concepts [Shapiro] |
8730 | 'Impredicative' definitions refer to the thing being described [Shapiro] |
23783 | Change exists, it is causal, and it needs an explanation [Williams,NE] |
23784 | Processes don't begin or end; they just change direction unexpectedly [Williams,NE] |
23790 | Processes are either strings of short unchanging states, or continuous and unreducible events [Williams,NE] |
23786 | The status quo is part of what exists, and so needs metaphysical explanation [Williams,NE] |
23768 | A metaphysic is a set of wider explanations derived from a basic ontology [Williams,NE] |
23773 | Humeans say properties are passive, possibility is vast, laws are descriptions, causation is weak [Williams,NE] |
23779 | We shouldn't posit the existence of anything we have a word for [Williams,NE] |
23780 | Every possible state of affairs is written into its originating powers [Williams,NE] |
23789 | Naming powers is unwise, because that it usually done by a single manifestation [Williams,NE] |
23775 | Powers are 'multi-track' if they can produce a variety of manifestations [Williams,NE] |
23771 | Fundamental physics describes everything in terms of powers [Williams,NE] |
23776 | Rather than pure powers or pure categoricals, I favour basics which are both at once [Williams,NE] |
23777 | Powers are more complicated than properties which are always on display [Williams,NE] |
23774 | There are basic powers, which underlie dispositions, potentialities, capacities etc [Williams,NE] |
23791 | Dispositions are just useful descriptions, which are explained by underlying powers [Williams,NE] |
23772 | If objects are property bundles, the properties need combining powers [Williams,NE] |
23788 | Four-Dimensional is Perdurantism (temporal parts), plus Eternalism [Williams,NE] |
15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
8725 | Rationalism tries to apply mathematical methodology to all of knowledge [Shapiro] |
23785 | Causation needs to explain stasis, as well as change [Williams,NE] |
23782 | Causation is the exercise of powers [Williams,NE] |
23787 | If causes and effects overlap, that makes changes impossible [Williams,NE] |
23778 | Powers contain lawlike features, pointing to possible future states [Williams,NE] |