60 ideas
12249 | 'Animal' is a genus and 'rational' is a specific difference [Oderberg] |
12242 | Definition distinguishes one kind from another, and individuation picks out members of the kind [Oderberg] |
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] |
12238 | The Aristotelian view is that numbers depend on (and are abstracted from) other things [Oderberg] |
12254 | Being is substantial/accidental, complete/incomplete, necessary/contingent, possible, relative, intrinsic.. [Oderberg] |
12253 | If tropes are in space and time, in what sense are they abstract? [Oderberg] |
12256 | We need to distinguish the essential from the non-essential powers [Oderberg] |
12252 | Empiricists gave up 'substance', as unknowable substratum, or reducible to a bundle [Oderberg] |
12241 | Essences are real, about being, knowable, definable and classifiable [Oderberg, by PG] |
12244 | Nominalism is consistent with individual but not with universal essences [Oderberg] |
12240 | Essentialism is the main account of the unity of objects [Oderberg] |
12247 | Essence is not explanatory but constitutive [Oderberg] |
12258 | Properties are not part of an essence, but they flow from it [Oderberg] |
12257 | Could we replace essence with collections of powers? [Oderberg] |
12236 | Leibniz's Law is an essentialist truth [Oderberg] |
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] |
12250 | Bodies have act and potency, the latter explaining new kinds of existence [Oderberg] |
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] |
12234 | Realism about possible worlds is circular, since it needs a criterion of 'possible' [Oderberg] |
12235 | Necessity of identity seems trivial, because it leaves out the real essence [Oderberg] |
12237 | Rigid designation has at least three essentialist presuppositions [Oderberg] |
2705 | How can intuitionists distinguish universal convictions from local cultural ones? [Hare] |
2712 | You can't use intuitions to decide which intuitions you should cultivate [Hare] |
2706 | Emotivists mistakenly think all disagreements are about facts, and so there are no moral reasons [Hare] |
2709 | Prescriptivism sees 'ought' statements as imperatives which are universalisable [Hare] |
2704 | If morality is just a natural or intuitive description, that leads to relativism [Hare] |
2703 | Descriptivism say ethical meaning is just truth-conditions; prescriptivism adds an evaluation [Hare] |
2707 | If there can be contradictory prescriptions, then reasoning must be involved [Hare] |
2708 | An 'ought' statement implies universal application [Hare] |
2711 | Prescriptivism implies a commitment, but descriptivism doesn't [Hare] |
2710 | Moral judgements must invoke some sort of principle [Hare] |
12245 | Essence is the source of a thing's characteristic behaviour [Oderberg] |
12246 | What makes Parmenidean reality a One rather than a Many? [Oderberg] |
12239 | The real essentialist is not merely a scientist [Oderberg] |
12243 | The reductionism found in scientific essentialism is mistaken [Oderberg] |