72 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] |
10987 | Three traditional names of rules are 'Simplification', 'Addition' and 'Disjunctive Syllogism' [Read] |
11004 | Necessity is provability in S4, and true in all worlds in S5 [Read] |
11018 | There are fuzzy predicates (and sets), and fuzzy quantifiers and modifiers [Read] |
11011 | Same say there are positive, negative and neuter free logics [Read] |
11020 | Realisms like the full Comprehension Principle, that all good concepts determine sets [Read] |
10986 | Not all validity is captured in first-order logic [Read] |
10972 | The non-emptiness of the domain is characteristic of classical logic [Read] |
11024 | Semantics must precede proof in higher-order logics, since they are incomplete [Read] |
10985 | We should exclude second-order logic, precisely because it captures arithmetic [Read] |
10970 | A theory of logical consequence is a conceptual analysis, and a set of validity techniques [Read] |
10984 | Logical consequence isn't just a matter of form; it depends on connections like round-square [Read] |
10973 | A theory is logically closed, which means infinite premisses [Read] |
11007 | Quantifiers are second-order predicates [Read] |
10978 | In second-order logic the higher-order variables range over all the properties of the objects [Read] |
10971 | A logical truth is the conclusion of a valid inference with no premisses [Read] |
10988 | Any first-order theory of sets is inadequate [Read] |
10975 | Compactness does not deny that an inference can have infinitely many premisses [Read] |
10974 | Compactness is when any consequence of infinite propositions is the consequence of a finite subset [Read] |
10977 | Compactness blocks the proof of 'for every n, A(n)' (as the proof would be infinite) [Read] |
10976 | Compactness makes consequence manageable, but restricts expressive power [Read] |
11014 | Self-reference paradoxes seem to arise only when falsity is involved [Read] |
11025 | Infinite cuts and successors seems to suggest an actual infinity there waiting for us [Read] |
10979 | Although second-order arithmetic is incomplete, it can fully model normal arithmetic [Read] |
10980 | Second-order arithmetic covers all properties, ensuring categoricity [Read] |
10997 | Von Neumann numbers are helpful, but don't correctly describe numbers [Read] |
11016 | Would a language without vagueness be usable at all? [Read] |
11019 | Supervaluations say there is a cut-off somewhere, but at no particular place [Read] |
11012 | A 'supervaluation' gives a proposition consistent truth-value for classical assignments [Read] |
11013 | Identities and the Indiscernibility of Identicals don't work with supervaluations [Read] |
10995 | A haecceity is a set of individual properties, essential to each thing [Read] |
11001 | Equating necessity with truth in every possible world is the S5 conception of necessity [Read] |
10989 | The standard view of conditionals is that they are truth-functional [Read] |
10992 | The point of conditionals is to show that one will accept modus ponens [Read] |
11017 | Some people even claim that conditionals do not express propositions [Read] |
10983 | Knowledge of possible worlds is not causal, but is an ontology entailed by semantics [Read] |
10982 | How can modal Platonists know the truth of a modal proposition? [Read] |
10996 | Actualism is reductionist (to parts of actuality), or moderate realist (accepting real abstractions) [Read] |
10981 | A possible world is a determination of the truth-values of all propositions of a domain [Read] |
11000 | If worlds are concrete, objects can't be present in more than one, and can only have counterparts [Read] |
3622 | The Cogito is not a syllogism but a self-evident intuition [Descartes] |
10998 | The mind abstracts ways things might be, which are nonetheless real [Read] |
11005 | Negative existentials with compositionality make the whole sentence meaningless [Read] |
10966 | A proposition objectifies what a sentence says, as indicative, with secure references [Read] |
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] |