36 ideas
| 7786 | Propositional logic handles negation, disjunction, conjunction; predicate logic adds quantifiers, predicates, relations [Girle] |
| 7798 | There are three axiom schemas for propositional logic [Girle] |
| 7799 | Proposition logic has definitions for its three operators: or, and, and identical [Girle] |
| 7797 | Axiom systems of logic contain axioms, inference rules, and definitions of proof and theorems [Girle] |
| 7794 | There are seven modalities in S4, each with its negation [Girle] |
| 7793 | ◊p → □◊p is the hallmark of S5 [Girle] |
| 7795 | S5 has just six modalities, and all strings can be reduced to those [Girle] |
| 7787 | Possible worlds logics use true-in-a-world rather than true [Girle] |
| 7788 | Modal logic has four basic modal negation equivalences [Girle] |
| 7796 | Modal logics were studied in terms of axioms, but now possible worlds semantics is added [Girle] |
| 7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
| 7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
| 19400 | Possibles demand existence, so as many of them as possible must actually exist [Leibniz] |
| 19401 | God's sufficient reason for choosing reality is in the fitness or perfection of possibilities [Leibniz] |
| 6472 | Continuity is a sufficient criterion for the identity of a rock, but not for part of a smooth fluid [Russell] |
| 6473 | Physical things are series of appearances whose matter obeys physical laws [Russell] |
| 6465 | We need not deny substance, but there seems no reason to assert it [Russell] |
| 6471 | The assumption by physicists of permanent substance is not metaphysically legitimate [Russell] |
| 7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
| 7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
| 19402 | The actual universe is the richest composite of what is possible [Leibniz] |
| 7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
| 6466 | Where possible, logical constructions are to be substituted for inferred entities [Russell] |
| 6467 | No sensibile is ever a datum to two people at once [Russell] |
| 6483 | Russell held that we are aware of states of our own brain [Russell, by Robinson,H] |
| 8244 | Sense-data are qualities devoid of subjectivity, which are the basis of science [Russell, by Deleuze/Guattari] |
| 6462 | Sense-data are not mental, but are part of the subject-matter of physics [Russell] |
| 6463 | Sense-data are objects, and do not contain the subject as part, the way beliefs do [Russell] |
| 6464 | Sense-data are usually objects within the body, but are not part of the subject [Russell] |
| 6459 | We do not know whether sense-data exist as objects when they are not data [Russell] |
| 6460 | 'Sensibilia' are identical to sense-data, without actually being data for any mind [Russell] |
| 6461 | Ungiven sense-data can no more exist than unmarried husbands [Russell] |
| 6458 | Individuating sense-data is difficult, because they divide when closely attended to [Russell] |
| 6469 | Sense-data may be subjective, if closing our eyes can change them [Russell] |
| 6470 | Matter is the limit of appearances as distance from the object diminishes [Russell] |
| 6468 | There is 'private space', and there is also the 'space of perspectives' [Russell] |