30 ideas
| 8092 | Logic was merely a branch of rhetoric until the scientific 17th century [Devlin] |
| 8081 | 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin] |
| 8085 | Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin] |
| 8086 | Predicate logic retains the axioms of propositional logic [Devlin] |
| 8091 | Situation theory is logic that takes account of context [Devlin] |
| 8089 | Montague's intensional logic incorporated the notion of meaning [Devlin] |
| 8087 | Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin] |
| 8082 | Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin] |
| 8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
| 8075 | Space and time are atomic in the arrow, and divisible in the tortoise [Devlin] |
| 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] |
| 8088 | People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin] |
| 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] |
| 8073 | How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin] |
| 8076 | The distinction between sentences and abstract propositions is crucial in logic [Devlin] |
| 468 | Musical performance can reveal a range of virtues [Damon of Ath.] |
| 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] |