64 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] |
| 15413 | With four tense operators, all complex tenses reduce to fourteen basic cases [Burgess] |
| 15415 | The temporal Barcan formulas fix what exists, which seems absurd [Burgess] |
| 15430 | Is classical logic a part of intuitionist logic, or vice versa? [Burgess] |
| 15431 | It is still unsettled whether standard intuitionist logic is complete [Burgess] |
| 15429 | Relevance logic's → is perhaps expressible by 'if A, then B, for that reason' [Burgess] |
| 15404 | Technical people see logic as any formal system that can be studied, not a study of argument validity [Burgess] |
| 15405 | Classical logic neglects the non-mathematical, such as temporality or modality [Burgess] |
| 15427 | The Cut Rule expresses the classical idea that entailment is transitive [Burgess] |
| 15421 | Classical logic neglects counterfactuals, temporality and modality, because maths doesn't use them [Burgess] |
| 15403 | Philosophical logic is a branch of logic, and is now centred in computer science [Burgess] |
| 15407 | Formalising arguments favours lots of connectives; proving things favours having very few [Burgess] |
| 15424 | Asserting a disjunction from one disjunct seems odd, but can be sensible, and needed in maths [Burgess] |
| 15409 | All occurrences of variables in atomic formulas are free [Burgess] |
| 15414 | The denotation of a definite description is flexible, rather than rigid [Burgess] |
| 15406 | 'Induction' and 'recursion' on complexity prove by connecting a formula to its atomic components [Burgess] |
| 15425 | The sequent calculus makes it possible to have proof without transitivity of entailment [Burgess] |
| 15426 | We can build one expanding sequence, instead of a chain of deductions [Burgess] |
| 15408 | 'Tautologies' are valid formulas of classical sentential logic - or substitution instances in other logics [Burgess] |
| 15418 | Validity (for truth) and demonstrability (for proof) have correlates in satisfiability and consistency [Burgess] |
| 15412 | Models leave out meaning, and just focus on truth values [Burgess] |
| 15411 | We only need to study mathematical models, since all other models are isomorphic to these [Burgess] |
| 15416 | We aim to get the technical notion of truth in all models matching intuitive truth in all instances [Burgess] |
| 15428 | The Liar seems like a truth-value 'gap', but dialethists see it as a 'glut' [Burgess] |
| 10185 | Set theory is the standard background for modern mathematics [Burgess] |
| 10184 | Structuralists take the name 'R' of the reals to be a variable ranging over structures, not a structure [Burgess] |
| 10189 | There is no one relation for the real number 2, as relations differ in different models [Burgess] |
| 10186 | If set theory is used to define 'structure', we can't define set theory structurally [Burgess] |
| 10187 | Abstract algebra concerns relations between models, not common features of all the models [Burgess] |
| 10188 | How can mathematical relations be either internal, or external, or intrinsic? [Burgess] |
| 12887 | A whole must have one characteristic, an internal relation, and a structure [Rescher/Oppenheim] |
| 15420 | De re modality seems to apply to objects a concept intended for sentences [Burgess] |
| 15419 | General consensus is S5 for logical modality of validity, and S4 for proof [Burgess] |
| 15417 | Logical necessity has two sides - validity and demonstrability - which coincide in classical logic [Burgess] |
| 15422 | Three conditionals theories: Materialism (material conditional), Idealism (true=assertable), Nihilism (no truth) [Burgess] |
| 15423 | It is doubtful whether the negation of a conditional has any clear meaning [Burgess] |
| 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] |