40 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] |
18739 | Three stages of philosophical logic: syntactic (1905-55), possible worlds (1963-85), widening (1990-) [Horsten/Pettigrew] |
7789 | Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle] |
18741 | Logical formalization makes concepts precise, and also shows their interrelation [Horsten/Pettigrew] |
7790 | If an argument is invalid, a truth tree will indicate a counter-example [Girle] |
18744 | Models are sets with functions and relations, and truth built up from the components [Horsten/Pettigrew] |
18740 | If 'exist' doesn't express a property, we can hardly ask for its essence [Horsten/Pettigrew] |
21812 | Being is the product of pure intellect [Plotinus] |
21817 | The One does not exist, but is the source of all existence [Plotinus] |
21824 | The One is a principle which transcends Being [Plotinus] |
21813 | Number determines individual being [Plotinus] |
7800 | Analytic truths are divided into logically and conceptually necessary [Girle] |
7801 | Possibilities can be logical, theoretical, physical, economic or human [Girle] |
7792 | A world has 'access' to a world it generates, which is important in possible worlds semantics [Girle] |
18745 | A Tarskian model can be seen as a possible state of affairs [Horsten/Pettigrew] |
18747 | The 'spheres model' was added to possible worlds, to cope with counterfactuals [Horsten/Pettigrew] |
18748 | Epistemic logic introduced impossible worlds [Horsten/Pettigrew] |
18746 | Possible worlds models contain sets of possible worlds; this is a large metaphysical commitment [Horsten/Pettigrew] |
18750 | Using possible worlds for knowledge and morality may be a step too far [Horsten/Pettigrew] |
5506 | If soul was like body, its parts would be separate, without communication [Plotinus] |
21827 | The movement of Soul is continuous, but we are only aware of the parts of it that are sensed [Plotinus] |
21828 | A person is the whole of their soul [Plotinus] |
21809 | Our soul has the same ideal nature as the oldest god, and is honourable above the body [Plotinus] |
21825 | The soul is outside of all of space, and has no connection to the bodily order [Plotinus] |
21826 | The Soul reasons about the Right, so there must be some permanent Right about which it reasons [Plotinus] |
6922 | Ecstasy is for the neo-Platonist the highest psychological state of man [Plotinus, by Feuerbach] |
21814 | How can multiple existence arise from the unified One? [Plotinus] |
21815 | Because the One is immobile, it must create by radiation, light the sun producing light [Plotinus] |
21816 | Soul is the logos of Nous, just as Nous is the logos of the One [Plotinus] |
21808 | Soul is author of all of life, and of the stars, and it gives them law and movement [Plotinus] |
21811 | Even the soul is secondary to the Intellectual-Principle [Nous], of which soul is an utterance [Plotinus] |