40 ideas
| 7490 | Because of Darwin, wisdom as a definite attainable state has faded [Watson] |
| 7461 | The three key ideas are the soul, Europe, and the experiment [Watson] |
| 7464 | The big idea: imitation, the soul, experiments, God, heliocentric universe, evolution? [Watson] |
| 7465 | Babylonian thinking used analogy, rather than deduction or induction [Watson] |
| 10888 | Sets can be defined by 'enumeration', or by 'abstraction' (based on a property) [Zalabardo] |
| 10889 | The 'Cartesian Product' of two sets relates them by pairing every element with every element [Zalabardo] |
| 10890 | A 'partial ordering' is reflexive, antisymmetric and transitive [Zalabardo] |
| 10886 | Determinacy: an object is either in a set, or it isn't [Zalabardo] |
| 10887 | Specification: Determinate totals of objects always make a set [Zalabardo] |
| 10897 | A first-order 'sentence' is a formula with no free variables [Zalabardo] |
| 10893 | Γ |= φ for sentences if φ is true when all of Γ is true [Zalabardo] |
| 10899 | Γ |= φ if φ is true when all of Γ is true, for all structures and interpretations [Zalabardo] |
| 10896 | Propositional logic just needs ¬, and one of ∧, ∨ and → [Zalabardo] |
| 10898 | The semantics shows how truth values depend on instantiations of properties and relations [Zalabardo] |
| 10902 | We can do semantics by looking at given propositions, or by building new ones [Zalabardo] |
| 10892 | We make a truth assignment to T and F, which may be true and false, but merely differ from one another [Zalabardo] |
| 10895 | 'Logically true' (|= φ) is true for every truth-assignment [Zalabardo] |
| 10900 | Logically true sentences are true in all structures [Zalabardo] |
| 10894 | A sentence-set is 'satisfiable' if at least one truth-assignment makes them all true [Zalabardo] |
| 10901 | Some formulas are 'satisfiable' if there is a structure and interpretation that makes them true [Zalabardo] |
| 10903 | A structure models a sentence if it is true in the model, and a set of sentences if they are all true in the model [Zalabardo] |
| 7466 | Mesopotamian numbers applied to specific things, and then became abstract [Watson] |
| 10891 | If a set is defined by induction, then proof by induction can be applied to it [Zalabardo] |
| 7477 | Modern democracy is actually elective oligarchy [Watson] |
| 7478 | Greek philosophers invented the concept of 'nature' as their special subject [Watson] |
| 5994 | Is the cosmos open or closed, mechanical or teleological, alive or inanimate, and created or eternal? [Robinson,TM, by PG] |
| 7462 | DNA mutation suggests humans and chimpanzees diverged 6.6 million years ago [Watson] |
| 7470 | During the rise of civilizations, the main gods changed from female to male [Watson] |
| 7474 | Hinduism has no founder, or prophet, or creed, or ecclesiastical structure [Watson] |
| 7479 | Modern Judaism became stabilised in 200 CE [Watson] |
| 7481 | The Israelites may have asserted the uniqueness of Yahweh to justify land claims [Watson] |
| 7480 | Monotheism was a uniquely Israelite creation within the Middle East [Watson] |
| 7471 | The Gathas (hymns) of Zoroastrianism date from about 1000 BCE [Watson] |
| 7473 | Zoroaster conceived the afterlife, judgement, heaven and hell, and the devil [Watson] |
| 7484 | Jesus never intended to start a new religion [Watson] |
| 7483 | Paul's early writings mention few striking episodes from Jesus' life [Watson] |
| 7475 | Confucius revered the spiritual world, but not the supernatural, or a personal god, or the afterlife [Watson] |
| 7476 | Taoism aims at freedom from the world, the body, the mind, and nature [Watson] |
| 7463 | The three basic ingredients of religion are: the soul, seers or priests, and ritual [Watson] |
| 7468 | In ancient Athens the souls of the dead are received by the 'upper air' [Watson] |