40 ideas
| 20678 | The Scientific Revolution was the discovery of our own ignorance [Harari] |
| 20686 | For millenia people didn't know how to convert one type of energy into another [Harari] |
| 10751 | Second-order logic needs the sets, and its consequence has epistemological problems [Rossberg] |
| 10757 | Henkin semantics has a second domain of predicates and relations (in upper case) [Rossberg] |
| 10759 | There are at least seven possible systems of semantics for second-order logic [Rossberg] |
| 10753 | Logical consequence is intuitively semantic, and captured by model theory [Rossberg] |
| 10752 | Γ |- S says S can be deduced from Γ; Γ |= S says a good model for Γ makes S true [Rossberg] |
| 10754 | In proof-theory, logical form is shown by the logical constants [Rossberg] |
| 10756 | A model is a domain, and an interpretation assigning objects, predicates, relations etc. [Rossberg] |
| 10758 | If models of a mathematical theory are all isomorphic, it is 'categorical', with essentially one model [Rossberg] |
| 10761 | Completeness can always be achieved by cunning model-design [Rossberg] |
| 10755 | A deductive system is only incomplete with respect to a formal semantics [Rossberg] |
| 3061 | Anaxarchus said that he was not even sure that he knew nothing [Anaxarchus, by Diog. Laertius] |
| 20692 | Money does produce happiness, but only up to a point [Harari] |
| 20663 | If a group is bound by gossip, the natural size is 150 people [Harari] |
| 20677 | Since 1500 human population has increased fourteenfold, and consumption far more [Harari] |
| 20688 | People 300m tons; domesticated animals 700m tons; larger wild animals 100m tons [Harari] |
| 20674 | The Nazi aim was to encourage progressive evolution, and avoid degeneration [Harari] |
| 20679 | We stabilise societies with dogmas, either of dubious science, or of non-scientific values [Harari] |
| 20690 | The state fostered individualism, to break the power of family and community [Harari] |
| 20689 | In 1750 losing your family and community meant death [Harari] |
| 20681 | The sacred command of capitalism is that profits must be used to increase production [Harari] |
| 20682 | The main rule of capitalism is that all other goods depend on economic growth [Harari] |
| 20683 | The progress of capitalism depends entirely on the new discoveries and gadgets of science [Harari] |
| 20687 | In capitalism the rich invest, and the rest of us go shopping [Harari] |
| 20685 | No market is free of political bias, and markets need protection of their freedoms [Harari] |
| 20693 | Freedom may work against us, as individuals can choose to leave, and make fewer commitments [Harari] |
| 20691 | Real peace is the implausibility of war (and not just its absence) [Harari] |
| 20684 | Financing is increasingly through credit rather than taxes; people prefer investing to taxation [Harari] |
| 20675 | The more you know about history, the harder it becomes to explain [Harari] |
| 20676 | History teaches us that the present was not inevitable, and shows us the possibilities [Harari] |
| 20671 | In order to explain both order and evil, a single evil creator is best, but no one favours that [Harari] |
| 20664 | Animism is belief that every part of nature is aware and feeling, and can communicate [Harari] |
| 20666 | Most polytheist recognise one supreme power or law, behind the various gods [Harari] |
| 20667 | Polytheism is open-minded, and rarely persecutes opponents [Harari] |
| 20665 | Mythologies are usual contracts with the gods, exchanging devotion for control of nature [Harari] |
| 20669 | Dualist religions see everything as a battleground of good and evil forces [Harari] |
| 20670 | Dualist religions say the cosmos is a battleground, so can’t explain its order [Harari] |
| 20673 | Manichaeans and Gnostics: good made spirit, evil made flesh [Harari] |
| 20668 | Monotheism appeared in Egypt in 1350 BCE, when the god Aten was declared supreme [Harari] |