66 ideas
7950 | Philosophy tries to explain how the actual is possible, given that it seems impossible [Macdonald,C] |
7923 | 'Did it for the sake of x' doesn't involve a sake, so how can ontological commitments be inferred? [Macdonald,C] |
7933 | Don't assume that a thing has all the properties of its parts [Macdonald,C] |
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] |
17963 | The facts of geometry, arithmetic or statics order themselves into theories [Hilbert] |
17966 | Axioms must reveal their dependence (or not), and must be consistent [Hilbert] |
15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
17967 | To decide some questions, we must study the essence of mathematical proof itself [Hilbert] |
17965 | The whole of Euclidean geometry derives from a basic equation and transformations [Hilbert] |
17964 | Number theory just needs calculation laws and rules for integers [Hilbert] |
7944 | Reduce by bridge laws (plus property identities?), by elimination, or by reducing talk [Macdonald,C] |
7938 | Relational properties are clearly not essential to substances [Macdonald,C] |
7967 | Being taller is an external relation, but properties and substances have internal relations [Macdonald,C] |
7965 | Does the knowledge of each property require an infinity of accompanying knowledge? [Macdonald,C] |
7934 | Tropes are abstract (two can occupy the same place), but not universals (they have locations) [Macdonald,C] |
7958 | Properties are sets of exactly resembling property-particulars [Macdonald,C] |
7972 | Tropes are abstract particulars, not concrete particulars, so the theory is not nominalist [Macdonald,C] |
7959 | How do a group of resembling tropes all resemble one another in the same way? [Macdonald,C] |
7960 | Trope Nominalism is the only nominalism to introduce new entities, inviting Ockham's Razor [Macdonald,C] |
7951 | Numerical sameness is explained by theories of identity, but what explains qualitative identity? [Macdonald,C] |
7964 | How can universals connect instances, if they are nothing like them? [Macdonald,C] |
7971 | Real Nominalism is only committed to concrete particulars, word-tokens, and (possibly) sets [Macdonald,C] |
7955 | Resemblance Nominalism cannot explain either new resemblances, or absence of resemblances [Macdonald,C] |
7961 | A 'thing' cannot be in two places at once, and two things cannot be in the same place at once [Macdonald,C] |
7926 | We 'individuate' kinds of object, and 'identify' particular specimens [Macdonald,C] |
7936 | Unlike bundles of properties, substances have an intrinsic unity [Macdonald,C] |
7930 | The bundle theory of substance implies the identity of indiscernibles [Macdonald,C] |
7932 | A phenomenalist cannot distinguish substance from attribute, so must accept the bundle view [Macdonald,C] |
7937 | When we ascribe a property to a substance, the bundle theory will make that a tautology [Macdonald,C] |
7939 | Substances persist through change, but the bundle theory says they can't [Macdonald,C] |
7940 | A substance might be a sequence of bundles, rather than a single bundle [Macdonald,C] |
7948 | A statue and its matter have different persistence conditions, so they are not identical [Macdonald,C] |
7929 | A substance is either a bundle of properties, or a bare substratum, or an essence [Macdonald,C] |
7941 | Each substance contains a non-property, which is its substratum or bare particular [Macdonald,C] |
7942 | The substratum theory explains the unity of substances, and their survival through change [Macdonald,C] |
7943 | A substratum has the quality of being bare, and they are useless because indiscernible [Macdonald,C] |
7927 | At different times Leibniz articulated three different versions of his so-called Law [Macdonald,C] |
7928 | The Identity of Indiscernibles is false, because it is not necessarily true [Macdonald,C] |
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] |
7947 | In continuity, what matters is not just the beginning and end states, but the process itself [Macdonald,C] |
17968 | By digging deeper into the axioms we approach the essence of sciences, and unity of knowedge [Hilbert] |