66 ideas
| 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] |
| 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] |
| 10185 | Set theory is the standard background for modern mathematics [Burgess] |
| 10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
| 10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
| 10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
| 10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
| 10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
| 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] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 20589 | Maybe a person's true self is their second-order desires [Tuckness/Wolf] |
| 20583 | If maximising pleasure needs measurement, so does fulfilling desires [Tuckness/Wolf] |
| 20584 | Desire satisfaction as the ideal is confused, because we desire what we judge to be good [Tuckness/Wolf] |
| 20598 | In a democracy, which 'people' are included in the decision process? [Tuckness/Wolf] |
| 20614 | People often have greater attachment to ethnic or tribal groups than to the state [Tuckness/Wolf] |
| 20596 | For global justice, adopt rules without knowing which country you will inhabit [Tuckness/Wolf] |
| 20593 | The veil of ignorance ensures both fairness and unanimity [Tuckness/Wolf] |
| 20608 | Unjust institutions may be seen as just; are they legitimate if just but seen as unjust? [Tuckness/Wolf] |
| 20597 | If winning elections depends on wealth, we have plutocracy instead of democracy [Tuckness/Wolf] |
| 20606 | Epistemic theories defend democracy as more likely to produce the right answer [Tuckness/Wolf] |
| 20600 | Which areas of public concern should be decided democratically, and which not? [Tuckness/Wolf] |
| 20609 | If several losing groups would win if they combine, a runoff seems called for [Tuckness/Wolf] |
| 20605 | Rights as interests (unlike rights as autonomy) supports mandatory voting [Tuckness/Wolf] |
| 20599 | How should democratic votes be aggregated? Can some person's votes count for more? [Tuckness/Wolf] |
| 20601 | Discussion before voting should be an essential part of democracy [Tuckness/Wolf] |
| 20613 | We have obligations to our family, even though we didn't choose its members [Tuckness/Wolf] |
| 20586 | Free speech does not include the right to shout 'Fire!' in a crowded theatre [Tuckness/Wolf] |
| 20587 | Most people want equality because they want a flourishing life [Tuckness/Wolf] |
| 20591 | If there is no suffering, wealth inequalities don't matter much [Tuckness/Wolf] |
| 20602 | Some rights are 'claims' that other people should act in a certain way [Tuckness/Wolf] |
| 20604 | Choice theory says protecting individual autonomy is basic (but needs to cover infants and animals) [Tuckness/Wolf] |
| 20603 | One theory (fairly utilitarian) says rights protect interests (but it needs to cover trivial interests) [Tuckness/Wolf] |
| 20607 | Having a right does not entail further rights needed to implement it [Tuckness/Wolf] |
| 20612 | If being subject to the law resembles a promise, we are morally obliged to obey it [Tuckness/Wolf] |
| 20611 | If others must obey laws that we like, we must obey laws that they like? [Tuckness/Wolf] |
| 20610 | Instead of against natural law, we might assess unjust laws against the values of the culture [Tuckness/Wolf] |
| 20617 | How should the punishment fit the crime (for stealing chickens?) [Tuckness/Wolf] |
| 20615 | Just wars: resist aggression, done on just cause, proportionate, last resort, not futile, legal [Tuckness/Wolf] |
| 20616 | During wars: proportional force, fair targets, fair weapons, safe prisoners, no reprisals [Tuckness/Wolf] |
| 20620 | If minority views are accepted in debate, then religious views must be accepted [Tuckness/Wolf] |
| 20619 | Is abortion the ending of a life, or a decision not to start one? [Tuckness/Wolf] |