88 ideas
| 18495 | The best philosophers I know are the best people I know [Heil] |
| 18494 | Using a technical vocabulary actually prevents discussion of the presuppositions [Heil] |
| 18506 | Questions of explanation should not be confused with metaphyics [Heil] |
| 18535 | Without abstraction we couldn't think systematically [Heil] |
| 18534 | Truth relates truthbearers to truthmakers [Heil] |
| 18531 | Philosophers of the past took the truthmaking idea for granted [Heil] |
| 18509 | Not all truths need truthmakers - mathematics and logic seem to be just true [Heil] |
| 9738 | Each line of a truth table is a model [Fitting/Mendelsohn] |
| 9727 | Modal logic adds □ (necessarily) and ◊ (possibly) to classical logic [Fitting/Mendelsohn] |
| 9726 | We let 'R' be the accessibility relation: xRy is read 'y is accessible from x' [Fitting/Mendelsohn] |
| 9737 | The symbol ||- is the 'forcing' relation; 'Γ ||- P' means that P is true in world Γ [Fitting/Mendelsohn] |
| 13136 | The prefix σ names a possible world, and σ.n names a world accessible from that one [Fitting/Mendelsohn] |
| 9734 | Modern modal logic introduces 'accessibility', saying xRy means 'y is accessible from x' [Fitting/Mendelsohn] |
| 9736 | A 'model' is a frame plus specification of propositions true at worlds, written < G,R,||- > [Fitting/Mendelsohn] |
| 13727 | A 'constant' domain is the same for all worlds; 'varying' domains can be entirely separate [Fitting/Mendelsohn] |
| 9735 | A 'frame' is a set G of possible worlds, with an accessibility relation R, written < G,R > [Fitting/Mendelsohn] |
| 9741 | Accessibility relations can be 'reflexive' (self-referring), 'transitive' (carries over), or 'symmetric' (mutual) [Fitting/Mendelsohn] |
| 13137 | Conj: a) if σ X∧Y then σ X and σ Y b) if σ ¬(X∧Y) then σ ¬X or σ ¬Y [Fitting/Mendelsohn] |
| 13140 | Bicon: a)if σ(X↔Y) then σ(X→Y) and σ(Y→X) b) [not biconditional, one or other fails] [Fitting/Mendelsohn] |
| 13138 | Disj: a) if σ ¬(X∨Y) then σ ¬X and σ ¬Y b) if σ X∨Y then σ X or σ Y [Fitting/Mendelsohn] |
| 13143 | Universal: a) if σ ¬◊X then σ.m ¬X b) if σ □X then σ.m X [m exists] [Fitting/Mendelsohn] |
| 13142 | Existential: a) if σ ◊X then σ.n X b) if σ ¬□X then σ.n ¬X [n is new] [Fitting/Mendelsohn] |
| 13141 | Negation: if σ ¬¬X then σ X [Fitting/Mendelsohn] |
| 13139 | Implic: a) if σ ¬(X→Y) then σ X and σ ¬Y b) if σ X→Y then σ ¬X or σ Y [Fitting/Mendelsohn] |
| 13144 | T reflexive: a) if σ □X then σ X b) if σ ¬◊X then σ ¬X [Fitting/Mendelsohn] |
| 13148 | 4r rev-trans: a) if σ.n □X then σ □X b) if σ.n ¬◊X then σ ¬◊X [n occurs] [Fitting/Mendelsohn] |
| 13147 | 4 transitive: a) if σ □X then σ.n □X b) if σ ¬◊X then σ.n ¬◊X [n occurs] [Fitting/Mendelsohn] |
| 13146 | B symmetric: a) if σ.n □X then σ X b) if σ.n ¬◊X then σ ¬X [n occurs] [Fitting/Mendelsohn] |
| 13145 | D serial: a) if σ □X then σ ◊X b) if σ ¬◊X then σ ¬□X [Fitting/Mendelsohn] |
| 13149 | S5: a) if n ◊X then kX b) if n ¬□X then k ¬X c) if n □X then k X d) if n ¬◊X then k ¬X [Fitting/Mendelsohn] |
| 9740 | If a proposition is possibly true in a world, it is true in some world accessible from that world [Fitting/Mendelsohn] |
| 9739 | If a proposition is necessarily true in a world, it is true in all worlds accessible from that world [Fitting/Mendelsohn] |
| 9742 | The system K has no accessibility conditions [Fitting/Mendelsohn] |
| 13114 | □P → P is not valid in D (Deontic Logic), since an obligatory action may be not performed [Fitting/Mendelsohn] |
| 9743 | The system D has the 'serial' conditon imposed on its accessibility relation [Fitting/Mendelsohn] |
| 9744 | The system T has the 'reflexive' conditon imposed on its accessibility relation [Fitting/Mendelsohn] |
| 9746 | The system K4 has the 'transitive' condition on its accessibility relation [Fitting/Mendelsohn] |
| 9745 | The system B has the 'reflexive' and 'symmetric' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9747 | The system S4 has the 'reflexive' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9748 | System S5 has the 'reflexive', 'symmetric' and 'transitive' conditions on its accessibility relation [Fitting/Mendelsohn] |
| 9404 | Modality affects content, because P→◊P is valid, but ◊P→P isn't [Fitting/Mendelsohn] |
| 13111 | Read epistemic box as 'a knows/believes P' and diamond as 'for all a knows/believes, P' [Fitting/Mendelsohn] |
| 13112 | In epistemic logic knowers are logically omniscient, so they know that they know [Fitting/Mendelsohn] |
| 13113 | F: will sometime, P: was sometime, G: will always, H: was always [Fitting/Mendelsohn] |
| 13729 | The Barcan corresponds to anti-monotonicity, and the Converse to monotonicity [Fitting/Mendelsohn] |
| 13728 | The Barcan says nothing comes into existence; the Converse says nothing ceases; the pair imply stability [Fitting/Mendelsohn] |
| 9725 | 'Predicate abstraction' abstracts predicates from formulae, giving scope for constants and functions [Fitting/Mendelsohn] |
| 18518 | Infinite numbers are qualitatively different - they are not just very large numbers [Heil] |
| 18500 | How could structures be mathematical truthmakers? Maths is just true, without truthmakers [Heil] |
| 18539 | Our categories lack the neat arrangement needed for reduction [Heil] |
| 18505 | Fundamental ontology aims at the preconditions for any true theory [Heil] |
| 18499 | Our quantifications only reveal the truths we accept; the ontology and truthmakers are another matter [Heil] |
| 18512 | Ontology aims to give the fundamental categories of being [Heil] |
| 18508 | Most philosophers now (absurdly) believe that relations fully exist [Heil] |
| 18532 | If causal relations are power manifestations, that makes them internal relations [Heil] |
| 18510 | We need properties to explain how the world works [Heil] |
| 18522 | Categorical properties were introduced by philosophers as actual properties, not if-then properties [Heil] |
| 18513 | Emergent properties will need emergent substances to bear them [Heil] |
| 18540 | Predicates only match properties at the level of fundamentals [Heil] |
| 18533 | In Fa, F may not be a property of a, but a determinable, satisfied by some determinate [Heil] |
| 18511 | Properties have causal roles which sets can't possibly have [Heil] |
| 18523 | Are all properties powers, or are there also qualities, or do qualities have the powers? [Heil] |
| 18524 | Properties are both qualitative and dispositional - they are powerful qualities [Heil] |
| 18498 | Abstract objects wouldn't be very popular without the implicit idea of truthmakers [Heil] |
| 18507 | Substances bear properties, so must be simple, and not consist of further substances [Heil] |
| 18515 | Spatial parts are just regions, but objects depend on and are made up of substantial parts [Heil] |
| 18516 | A 'gunky' universe would literally have no parts at all [Heil] |
| 18514 | Many wholes can survive replacement of their parts [Heil] |
| 18517 | Dunes depend on sand grains, but line segments depend on the whole line [Heil] |
| 13730 | The Indiscernibility of Identicals has been a big problem for modal logic [Fitting/Mendelsohn] |
| 18502 | If basic physics has natures, then why not reality itself? That would then found the deepest necessities [Heil] |
| 18496 | If possible worlds are just fictions, they can't be truthmakers for modal judgements [Heil] |
| 13725 | □ must be sensitive as to whether it picks out an object by essential or by contingent properties [Fitting/Mendelsohn] |
| 13731 | Objects retain their possible properties across worlds, so a bundle theory of them seems best [Fitting/Mendelsohn] |
| 13726 | Counterpart relations are neither symmetric nor transitive, so there is no logic of equality for them [Fitting/Mendelsohn] |
| 18525 | Mental abstraction does not make what is abstracted mind-dependent [Heil] |
| 18504 | Only particulars exist, and generality is our mode of presentation [Heil] |
| 18503 | You can think of tomatoes without grasping what they are [Heil] |
| 18538 | Non-conscious thought may be unlike conscious thought [Heil] |
| 18537 | Linguistic thought is just as imagistic as non-linguistic thought [Heil] |
| 17722 | The concept 'red' is tied to what actually individuates red things [Peacocke] |
| 18536 | The subject-predicate form reflects reality [Heil] |
| 18497 | Many reject 'moral realism' because they can't see any truthmakers for normative judgements [Heil] |
| 18519 | If there were infinite electrons, they could vanish without affecting total mass-energy [Heil] |
| 18526 | We should focus on actual causings, rather than on laws and causal sequences [Heil] |
| 18527 | Probabilistic causation is not a weak type of cause; it is just a probability of there being a cause [Heil] |
| 18520 | Electrons are treated as particles, but they lose their individuality in relations [Heil] |
| 18501 | Maybe the universe is fine-tuned because it had to be, despite plans by God or Nature? [Heil] |