45 ideas
| 20678 | The Scientific Revolution was the discovery of our own ignorance [Harari] |
| Full Idea: The great discovery of the Scientific Revolution was that humans do not know the answers to their most important question. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 14 'Ignoramus') | |
| A reaction: I think of that revolution as raising the bar in epistemology, but this idea gives a motivation for doing so. Why the discovery then, and not before? |
| 20686 | For millenia people didn't know how to convert one type of energy into another [Harari] |
| Full Idea: For millenia people didn't know how to convert one type of energy into another, …and the only machine capable of performing energy conversion was the body. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 17 'Intro') | |
| A reaction: Hence the huge and revolutionary importance of the steam engine and the electricity generator. |
| 18781 | Inconsistency doesn't prevent us reasoning about some system [Mares] |
| Full Idea: We are able to reason about inconsistent beliefs, stories, and theories in useful and important ways | |
| From: Edwin D. Mares (Negation [2014], 1) |
| 18789 | Intuitionist logic looks best as natural deduction [Mares] |
| Full Idea: Intuitionist logic appears most attractive in the form of a natural deduction system. | |
| From: Edwin D. Mares (Negation [2014], 5.5) |
| 18790 | Intuitionism as natural deduction has no rule for negation [Mares] |
| Full Idea: In intuitionist logic each connective has one introduction and one elimination rule attached to it, but in the classical system we have to add an extra rule for negation. | |
| From: Edwin D. Mares (Negation [2014], 5.5) | |
| A reaction: How very intriguing. Mares says there are other ways to achieve classical logic, but they all seem rather cumbersome. |
| 18787 | Three-valued logic is useful for a theory of presupposition [Mares] |
| Full Idea: One reason for wanting a three-valued logic is to act as a basis of a theory of presupposition. | |
| From: Edwin D. Mares (Negation [2014], 3.1) | |
| A reaction: [He cites Strawson 1950] The point is that you can get a result when the presupposition does not apply, as in talk of the 'present King of France'. |
| 18793 | Material implication (and classical logic) considers nothing but truth values for implications [Mares] |
| Full Idea: The problem with material implication, and classical logic more generally, is that it considers only the truth value of formulas in deciding whether to make an implication stand between them. It ignores everything else. | |
| From: Edwin D. Mares (Negation [2014], 7.1) | |
| A reaction: The obvious problem case is conditionals, and relevance is an obvious extra principle that comes to mind. |
| 18784 | In classical logic the connectives can be related elegantly, as in De Morgan's laws [Mares] |
| Full Idea: Among the virtues of classical logic is the fact that the connectives are related to one another in elegant ways that often involved negation. For example, De Morgan's Laws, which involve negation, disjunction and conjunction. | |
| From: Edwin D. Mares (Negation [2014], 2.2) | |
| A reaction: Mares says these enable us to take disjunction or conjunction as primitive, and then define one in terms of the other, using negation as the tool. |
| 18786 | Excluded middle standardly implies bivalence; attacks use non-contradiction, De M 3, or double negation [Mares] |
| Full Idea: On its standard reading, excluded middle tells us that bivalence holds. To reject excluded middle, we must reject either non-contradiction, or ¬(A∧B) ↔ (¬A∨¬B) [De Morgan 3], or the principle of double negation. All have been tried. | |
| From: Edwin D. Mares (Negation [2014], 2.2) |
| 18780 | Standard disjunction and negation force us to accept the principle of bivalence [Mares] |
| Full Idea: If we treat disjunction in the standard way and take the negation of a statement A to mean that A is false, accepting excluded middle forces us also to accept the principle of bivalence, which is the dictum that every statement is either true or false. | |
| From: Edwin D. Mares (Negation [2014], 1) | |
| A reaction: Mates's point is to show that passively taking the normal account of negation for granted has important implications. |
| 18782 | The connectives are studied either through model theory or through proof theory [Mares] |
| Full Idea: In studying the logical connectives, philosophers of logic typically adopt the perspective of either model theory (givng truth conditions of various parts of the language), or of proof theory (where use in a proof system gives the connective's meaning). | |
| From: Edwin D. Mares (Negation [2014], 1) | |
| A reaction: [compressed] The commonest proof theory is natural deduction, giving rules for introduction and elimination. Mates suggests moving between the two views is illuminating. |
| 18783 | Many-valued logics lack a natural deduction system [Mares] |
| Full Idea: Many-valued logics do not have reasonable natural deduction systems. | |
| From: Edwin D. Mares (Negation [2014], 1) |
| 18792 | Situation semantics for logics: not possible worlds, but information in situations [Mares] |
| Full Idea: Situation semantics for logics consider not what is true in worlds, but what information is contained in situations. | |
| From: Edwin D. Mares (Negation [2014], 6.2) | |
| A reaction: Since many theoretical physicists seem to think that 'information' might be the most basic concept of a natural ontology, this proposal is obviously rather appealing. Barwise and Perry are the authors of the theory. |
| 18785 | Consistency is semantic, but non-contradiction is syntactic [Mares] |
| Full Idea: The difference between the principle of consistency and the principle of non-contradiction is that the former must be stated in a semantic metalanguage, whereas the latter is a thesis of logical systems. | |
| From: Edwin D. Mares (Negation [2014], 2.2) |
| 18788 | For intuitionists there are not numbers and sets, but processes of counting and collecting [Mares] |
| Full Idea: For the intuitionist, talk of mathematical objects is rather misleading. For them, there really isn't anything that we should call the natural numbers, but instead there is counting. What intuitionists study are processes, such as counting and collecting. | |
| From: Edwin D. Mares (Negation [2014], 5.1) | |
| A reaction: That is the first time I have seen mathematical intuitionism described in a way that made it seem attractive. One might compare it to a metaphysics based on processes. Apparently intuitionists struggle with infinite sets and real numbers. |
| 18791 | In 'situation semantics' our main concepts are abstracted from situations [Mares] |
| Full Idea: In 'situation semantics' individuals, properties, facts, and events are treated as abstractions from situations. | |
| From: Edwin D. Mares (Negation [2014], 6.1) | |
| A reaction: [Barwise and Perry 1983 are cited] Since I take the process of abstraction to be basic to thought, I am delighted to learn that someone has developed a formal theory based on it. I am immediately sympathetic to situation semantics. |
| 20692 | Money does produce happiness, but only up to a point [Harari] |
| Full Idea: An interesting conclusion (from questionnaires) is that money does indeed bring happiness. But only up to a point, and beyond that point it has little significance. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 19 'Counting') | |
| A reaction: The question is whether that flattening-off point is relative to those around us, or absolute, according to the needs of living. Though these two may not be separate. |
| 20663 | If a group is bound by gossip, the natural size is 150 people [Harari] |
| Full Idea: Sociological research has shown that the maximum 'natural' size of a group bound by gossip is about 150 individuals. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 02 'Legend') | |
| A reaction: On the other hand, most of us can learn the names of a group of about 450. Maybe the 'known' group and the 'gossip' group are equally significant. Not much use for a modern state, but of interest to communitarians. |
| 20677 | Since 1500 human population has increased fourteenfold, and consumption far more [Harari] |
| Full Idea: In the year 1500 there were about 500 million Homo sapiens in the world. Today there are 7 billion. …Human population has increased fourteenfold, our production 240-fold, and energy consumption 115-fold. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 14 'Discovery') | |
| A reaction: We really need to grasp how extraordinary this is. |
| 20688 | People 300m tons; domesticated animals 700m tons; larger wild animals 100m tons [Harari] |
| Full Idea: The combined mass of homo sapiens is about 300 million tons; the mass of all domesticated farmyard animals is about 700 million tons; the mass of the surviving larger wild animals (from porcupines up) is less than 100 million tons. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 18 'Permanent') | |
| A reaction: These really are figures that deserve much wider currency. Every school entrance hall needs a board with a few of the basic dramatic statistics about human life on Earth. |
| 20674 | The Nazi aim was to encourage progressive evolution, and avoid degeneration [Harari] |
| Full Idea: The main ambition of the Nazis was to protect humankind from degeneration and encourage its progressive evolution. …Given the state of scientific knowledge in 1933, Nazi beliefs were hardly outside the pale. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Worship') | |
| A reaction: It still sounds a fairly worthy ambition, close to the heart of educationalists everywhere. The problems start with the definition of 'degeneration' and 'progress'. |
| 20679 | We stabilise societies with dogmas, either of dubious science, or of non-scientific values [Harari] |
| Full Idea: Modern attempts to stabilise the sociopolitical order either declare a scientific theory (such as racial theories for Nazis, or economic ones for Communists) to be an absolute truths, or declare non-scientific dogmas (such as liberal values) | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 14 'Ignoramus') | |
| A reaction: [compressed] |
| 20690 | The state fostered individualism, to break the power of family and community [Harari] |
| Full Idea: States and markets use their growing power to weaken the bonds of family and community. They made an offer that couldn't be refused - 'become individuals' (over marriage, jobs and residence). The 'romantic individual' is not a rebel against the state. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 18 'Collapse') | |
| A reaction: [compressed] See the film 'Breaking the Waves'. An interesting slant on the Romantic movement. See Wordsworth's 'Michael'. Capitalism needs shoppers with their own money, and a mobile workforce. |
| 20689 | In 1750 losing your family and community meant death [Harari] |
| Full Idea: A person who lost her family and community around 1750 was as good as dead. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 18 'Collapse') | |
| A reaction: This is a very good advert for liberal individualism, and marks the downside of 'too much community'. |
| 20681 | The sacred command of capitalism is that profits must be used to increase production [Harari] |
| Full Idea: In the new capitalist creed, the first and most sacred commandment is: The profits of production must be reinvested in increasing production. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 16 'Growing') | |
| A reaction: In this sense, capitalism is less greedy than its predecessors. 17th century aristocratic monopolists simply spent the profits of their activities. See the gorgeous clothes then (and pyramids and palaces), and the quiet suits of capitalists. |
| 20682 | The main rule of capitalism is that all other goods depend on economic growth [Harari] |
| Full Idea: The principle tenet of capitalism is that economic growth is the supreme good, or at least a proxy for it, because justice, freedom, and even happiness all depend on economic growth. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 16 'Growing') | |
| A reaction: In this respect, the main opponent of captitalism is green politics, rather than marxism. |
| 20683 | The progress of capitalism depends entirely on the new discoveries and gadgets of science [Harari] |
| Full Idea: The history of capitalism is unintelligible without taking science into account. …The human economy has managed to keep on going only thanks to the fact that scientists come up with a new discovery or gadget every few years. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 16 'Growing') | |
| A reaction: For example, the desperate but unconvincing attempts to persuade us of the novelty of new models of car. Built-in obsolescence is needed once a design becomes static. |
| 20687 | In capitalism the rich invest, and the rest of us go shopping [Harari] |
| Full Idea: The supreme commandment of the rich is 'invest!', and the supreme commandment of the rest of us is 'buy!' | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 17 'Age') | |
| A reaction: Hence not only do the rich get much richer, while most of us remain roughly where we were, but there is a huge gulf between the investors and the non-investors. Encouraging small investors is a step forward. |
| 20685 | No market is free of political bias, and markets need protection of their freedoms [Harari] |
| Full Idea: There is no such thing as a market free of all political bias, …and markets by themselves offer no protection against fraud, theft and violence. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 16 'Cult') | |
| A reaction: Is this in theory, or in practice? In Sicily the free market has been a tool of the mafia. |
| 20693 | Freedom may work against us, as individuals can choose to leave, and make fewer commitments [Harari] |
| Full Idea: The freedom we value so highly may work against us. We can choose our spouses, friends and neighbours, but they can choose to leave us. With the individual wielding unprecedented power to decide her own path, we find it ever harder to make commitments. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 19 'Counting') | |
| A reaction: This is the worry of the communitarian. I take freedom to be a great social virtue - but an overrated one. |
| 20691 | Real peace is the implausibility of war (and not just its absence) [Harari] |
| Full Idea: Real peace is not the mere absence of war. Real peace is the implausibility of war. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 18 'Pax') | |
| A reaction: I have a nasty feeling that war only becomes implausible because it hasn't happened for a long time. War looked implausible for Britain in 1890. War certainly now looks implausible in western Europe. |
| 20684 | Financing is increasingly through credit rather than taxes; people prefer investing to taxation [Harari] |
| Full Idea: The European conquest of the world was increasingly financed through credit rather than taxes. …Nobody wants to pay taxes, but everyone is happy to invest. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 16 'Columbus') | |
| A reaction: This is presumably the mechanism that drives the unstoppable increase of the gulf between the rich and the poor in modern times. With investment, the rich get richer. |
| 13304 | Learned men gain more in one day than others do in a lifetime [Posidonius] |
| Full Idea: In a single day there lies open to men of learning more than there ever does to the unenlightened in the longest of lifetimes. | |
| From: Posidonius (fragments/reports [c.95 BCE]), quoted by Seneca the Younger - Letters from a Stoic 078 | |
| A reaction: These remarks endorsing the infinite superiority of the educated to the uneducated seem to have been popular in late antiquity. It tends to be the religions which discourage great learning, especially in their emphasis on a single book. |
| 20675 | The more you know about history, the harder it becomes to explain [Harari] |
| Full Idea: A distinguishing mark of history is that the better you know a historical period, the harder it becomes to explain why things happened one way and not another. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 13 'Hindsight') | |
| A reaction: Presumaby that means it resembles statistics. Each individual reading is perplexing, but some patterns emerge on the large scale. |
| 20676 | History teaches us that the present was not inevitable, and shows us the possibilities [Harari] |
| Full Idea: We study history not to know the future but to widen our horizons, to understand that our present situation is neither natural nor inevitable, and the we consequently have many more possibilities before us than we can imagine. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 13 'Hindsight') | |
| A reaction: On the whole winners forget history, and losers are branded through and through with it. If you don't know history, you can never understand the latter group. |
| 20820 | Time is an interval of motion, or the measure of speed [Posidonius, by Stobaeus] |
| Full Idea: Posidonius defined time thus: it is an interval of motion, or the measure of speed and slowness. | |
| From: report of Posidonius (fragments/reports [c.95 BCE]) by John Stobaeus - Anthology 1.08.42 | |
| A reaction: Hm. Can we define motion or speed without alluding to time? Looks like we have to define them as a conjoined pair, which means we cannot fully understand either of them. |
| 20671 | In order to explain both order and evil, a single evil creator is best, but no one favours that [Harari] |
| Full Idea: Monotheism explains order but not evil, and dualist religion explains evil but not order. One logical solution is a single omnipotent God who created the universe, and is evil - but nobody in history has had much stomach for that belief. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Battle') | |
| A reaction: Eh? Is there not also good, which also needs explaining? And there is some chaos to be explained too. Hume offers the best explanations. An inexperienced god, a team of squabbling gods, a god with shifting moods…. Study the facts first. |
| 20664 | Animism is belief that every part of nature is aware and feeling, and can communicate [Harari] |
| Full Idea: Animism is the belief that almost every place, every animal, every plant and every natural phenomenon has awareness and feelings, and can communicated direct with humans. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 03 'Talking') | |
| A reaction: So does this count as a 'supernatural' belief system? It seems not, if the awareness is integral to the natural feature, and dies with it. Panpsychism is not supernatural either. A problem for anyone trying to define Naturalism. |
| 20666 | Most polytheist recognise one supreme power or law, behind the various gods [Harari] |
| Full Idea: Polytheism does not necessarily dispute the existence of a single power or law governing the entire universe. Most poytheist and even animist religions recognised such a supreme power that stands behind all the different gods, demons and holy rocks. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Benefits') | |
| A reaction: Presumably this one supreme power was always taken to be too remote for communication or worship. Are the other gods seen as slaves, or friends, or ambassadors of the Supreme One? |
| 20667 | Polytheism is open-minded, and rarely persecutes opponents [Harari] |
| Full Idea: Polytheism is inherently open-minded, and rarely persecutes 'heretics' and 'infidels'. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Benefits') | |
| A reaction: The Old Testament tells of the Jews turning on local pagans, and India was presumably tolerant Hindus encountering less tolerant Muslims. Then there's Christians in Africa. Dreadful bunch, the monotheists. Romans killed very few Christians. |
| 20665 | Mythologies are usual contracts with the gods, exchanging devotion for control of nature [Harari] |
| Full Idea: Much of ancient mythology is a legal contract in which humans promise everlasting devotion to the gods in exchange for mastery over plants and animals. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Silencing') | |
| A reaction: [He cites the first book of Genesis] So how readily do you swith allegiance, if someone else's gods are more successful? Why be loyal a loser. It should be like shopping - but I bet it wasn't. |
| 20669 | Dualist religions see everything as a battleground of good and evil forces [Harari] |
| Full Idea: Polytheism gave birth to monotheism, and to dualistic religions. Dualism explains that the entire universe is a battleground between good and evil forces, and everything that happens is part of that struggle. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Battle') | |
| A reaction: Presumably we are supposed to support the good guys, so the gods are not equals. God v Satan seems the right model, but Satan has to be beyond God's control, or else the problem of evil has to be solved. Empedocles held something like this. |
| 20670 | Dualist religions say the cosmos is a battleground, so can’t explain its order [Harari] |
| Full Idea: Dualist religions solve the problem of evil, but are unnerved by the Problem of Order. …If Good and Evil battle for control of the world, who enforces the laws governing this cosmic war? | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Battle') | |
| A reaction: You might explain it if one side was persistently winning, which is roughly God v Satan. |
| 20673 | Manichaeans and Gnostics: good made spirit, evil made flesh [Harari] |
| Full Idea: Manichaeans and Gnostics argued that the good god created the spirit and the soul, whereas matter and bodes are the creation of the evil god. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'Battle') | |
| A reaction: Hm. What motivated the evil god to do that? The evil god's achievement looks a lot more impressive. |
| 20668 | Monotheism appeared in Egypt in 1350 BCE, when the god Aten was declared supreme [Harari] |
| Full Idea: The first monotheist religion known to us appeared in Egypt c.1350 BCE, when Pharaoh Akenaten declared that one of minor deities of the Egyptian pantheon, the god Aten, was in fact the supreme power ruling the universe. | |
| From: Yuval Noah Harari (Sapiens: brief history of humankind [2014], 12 'God') | |
| A reaction: Zeus seems to have started like a tribal chief, and eventually turned into something like God. |