“The sole light fell from a smokehole in the ceiling and the woman knelt there at a low clay brasero and turned tortillas on a cracked and ancient clay comal while the thin smoke rose up the blackened wall and vanished overhead.”—Cormac McCarthy, The Crossing
“Suppose you ask where a particular comet will be seen in the sky in fifty years time, given where it is now. Well, the prevailing conception [of physics] will probably do, for that. It will make a prediction and it can only be in one place: only one thing will happen, and anything that doesn’t happen, couldn’t have. But ask a slightly different question, ask where we could make the comet go—we—and it’s no good replying that we will make it go wherever the laws of motion tell us to make it go, because the question is about what is possible, and it requires the mode of explanation that makes the concept of possibility legitimate.”—David Deutsch
“I think that this fashionable reductionism is just a mistake. I’m sure that free will exists. However, I think that free will is one of a constellation of emergent, abstract (we’re not exactly sure what proportion free will is abstract or emergent) properties, that are not yet understood. Things like consciousness, creativity, choice, free will, and so on—we do have good explanations about them at the emergent level, but we don’t understand them well enough to make artificial ones. I say in the book that my criterion for judging any theory of consciousness, free will, and so on, is: can you program it? If you can’t program it, then I cannot take seriously your theory of it. Now, I don’t have a theory of it, I only have a theory that it exists. If someone says that it doesn’t exist because we can explain everything without invoking it, then I want to see those explanations.”—David Deutsch
“Easy to see that naught save sorrow could bring a man to such a view of things. And yet a sorrow for which there can be no help is no sorrow. It is some dark sister traveling in sorrow’s clothing. Men do not turn from God so easily you see. Not so easily. Deep in each man is the knowledge that something knows of his existence. Something knows, and cannot be fled nor hid from. To imagine otherwise is to imagine the unspeakable. It was never that this man ceased to believe in God. No. It was rather that he came to believe terrible things of Him.”—Cormac McCarthy, The Crossing
“Many ideas may be excellent as parts of a great whole, which, when violently torn from their connection, will not only cease to be excellent, but may in some cases become positively injurious.”—William Godwin (1793:121)
“But on principle it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.”—Einstein to Heisenberg
“It’s a beautiful theory, but more to the point, it’s how the world is: you and I are collections of, not just particles at particular positions at each instant, but of matrices, walking around, performing measurements, perceiving the world and ourselves. You may not want to be a bunch of matrices; I quite like the idea. But either way we have no choice: if we want to understand the physical world at the deepest level currently known to human beings, it has to be via quantum theory.”—David Deutsch
“Rudimentary organs may be compared with the letters in a word still retained in the spelling but become useless in pronunciation, but which serve as a clue in seeking for its derivation.”—Darwin 1859 432
“The Greeks always thought of personality as actively related to the world (in fact, to two worlds, the world of nature and the world of human society) and not as isolated from it. Therefore Greek expressions of personal emotion and thought have nothing purely and exclusively subjective in them: it might rather be said that a poet like Archilochus has learnt how to express in his own personality the whole objective world and its laws—to represent them in himself. Personality, for the Greeks, gains its liberty and its consciousness of selfhood not by abandoning itself to subjective thought and feeling, but by making itself an objective thing; and, as it realizes that it is a separate world opposed to the external law, it discovers its own inner laws.”—Werner Jaeger, Paideia 1.117
“It’s true that you worry about the fact that they’ll be able to store information better, and have more information about people, and whether that will produce a Big Brother. That depends on the attitude of the leaders of society. Rather interestingly, the country which is more democratic, and which is less interested in all the information about what everybody is doing, to make sure they’re not doing something wrong, is where the computers are developed the most. And the place where’d you think the government would find the computer the greatest use, because you can file all the information about everybody—they don’t develop the computer very much and they don’t know how to use them.”—Feynman (1985)
The Washington Post printed an interesting argument from a new book by former Supreme Court Justice John Paul Stevens:
The Second Amendment expressly endorsed the substantive common-law rule that protected the citizen’s right (and duty) to keep and bear arms when serving in a state militia. In its decision in Heller, however, the majority interpreted the amendment as though its draftsmen were primarily motivated by an interest in protecting the common-law right of self-defense. But that common-law right is a procedural right that has always been available to the defendant in criminal proceedings in every state. The notion that the states were concerned about possible infringement of that right by the federal government is really quite absurd.
As a result of the rulings in Heller and McDonald, the Second Amendment, which was adopted to protect the states from federal interference with their power to ensure that their militias were “well regulated,” has given federal judges the ultimate power to determine the validity of state regulations of both civilian and militia-related uses of arms. That anomalous result can be avoided by adding five words to the text of the Second Amendment to make it unambiguously conform to the original intent of its draftsmen. As so amended, it would read:
“A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms when serving in the Militia shall not be infringed.”
I look forward to reading his book. The Supreme Court serves the important scholarly function of interpreting what the constitution means—what knowledge its language was meant to encode and how we might say it more clearly—but our job as citizens is to take its results and ask further: is that what we want it to say? That’s the genius of it, not that it contains infallible knowledge waiting to be correctly deciphered, but that it provides for its own improvement. This political experiment was part of a larger intellectual struggle (which we call the Enlightenment) to reject the very idea of infallibility or authority, not merely in politics or religion, but in knowledge generally.
“With anything you think you know a bit about, you’re probably tempted to rely on your own experience to make an inductive generalization. That can work if you really know what you’re talking about, but it doesn’t work if you’re just using that way of doing it, on another context, where your knowledge is not so secure.”—This comes from the lectures of Marianne Talbot, Critical Reasoning for Beginners, at Oxford (lecture 4 approx. 30:50), which are otherwise very good lectures introducing the principles of argumentation. Induction is a type of commonsense, and so when Hume explained why it was wrong in principle, even he continued to treat it as if it were true, rather like we still speak about the sun rising. If you understand inductive logic as a fallacy, rather than a weaker branch of logic, and reject it entirely, its absence seems elegant, and the inductive sections of philosophy lectures are humorous, not because the professors are stupid, but precisely because they are so smart. Talbot invariably has to equivocate whenever analyzing inductive arguments, and her distaste for them is clear to the audience, but I think not really to herself. This quote is the highlight of that cognitive dissonance. She has just suddenly abandoned an example as bad, before completely expounding it, and proceeds in these sentences to explain that induction is false, even as she seems satisfied that she has justified it, and moves on to the next topic.
“Most information, if it were instantiated in some physical object, would not have the property that when it acts on something it is conserved. So, for example, a book with a misprint, in the following edition of the book, the misprint is corrected; if the book is a good book, then the version without misprints is capable of surviving. So, it’s rather like genes: regions of DNA which are junk DNA, which are not used for anything, are just information, and the rest are genes. Similarly, most information does not consist of knowledge, because it doesn’t satisfy the fundamental property of a constructor, that it can produce something and then be able to reproduce it again, without limit.”—David Deutsch on distinguishing information and knowledge.
“It is indeed very strange, but I think inescapable, that human beings—or rather people, creative entities—have a special place in nature, because the overwhelming majority of processes that are possible are possible only when people are involved. This is a break with the Galilean tradition, which said that there’s nothing important about people; but in fact the thing that is important about people is the very thing that back 400 years ago was important to deny about people: that is, people are not supernatural, they’re part of the physical world, and they’re the most important part of the physical world. I’ve focused in my talk about what people can do (that is, almost everything requires people to do), but there’s also the converse question, what can the world make people do, that is, how would you predict the behavior of human beings? Well, if you think about scientists performing experiments and celebrating when they succeed and make a discovery and so on, you couldn’t predict the set of all such things unless you knew all the laws of physics. So human beings, uniquely, are entities which you can’t predict the behavior of without knowing everything about the universe.”—David Deutsch
“What Darwin showed us was that the mechanism of natural selection can, in principle, simulate the actions of the Creator, and His purpose and design, and that it can also simulate rational human action directed towards a purpose or aim.”—Karl Popper, Evolution and the Tree of Knowledge
“The soap bubble consists of two subsystems which are both clouds and which control each other: without the air, the soapy film would collapse, and we should have only a drop of soapy water. Without the soapy film, the air would be uncontrolled: it would diffuse, ceasing to exist as a system. Thus the control is mutual; it is plastic, and of a feed-back character. Yet it is possible to make a distinction between the controlled system (the air) and the controlling system (the film): the enclosed air is not only more cloudy than the enclosing film, but it also ceases to be a physical (self-interacting) system if the film is removed. As against this, the film, after the removal of air, will form a droplet which, though of a different shape, may still be said to be a physical system.”—Karl Popper, Of Clouds and Clocks
“One of the first items sold on [eBay] was a broken laser pointer for $14.83. Astonished, Omidyar contacted the winning bidder to ask if he understood that the laser pointer was broken. In his responding email, the buyer explained: ‘I’m a collector of broken laser pointers.’”—
When we moved out of the greater New York City area for the Catskill mountains when I was half-way through kindergarten, my father bought a personal computer and taught himself how to program. He made a living doing “desktop publishing,” which was a thing that happened between the advent of personal computing and its ubiquitization. After the Windows revolution, when people started doing their own desktop publishing, he was asked to beta test dial-up internet service, and so we became one of the first households in our area with access. When they didn’t heed any of his criticisms, he decided to start his own ISP, since he was looking for a new line of work anyway.
In those beta-testing days, he would log on briefly and download messages from various groups of other nerds who shared his programming interests, and then read them offline, before logging in again to reply. It was always a mysterious apparatus to me and my father wasn’t keen on explanations: he usually thought it more prudent to just fix my computer problems. To some degree I think I was rebelling when I was offline for the most part between 2001-2005.
What happened in 2005? I discovered that I could be in touch with people all over the world who were also studying Greek either professionally or for their own amusement like me. My progress increased rapidly immediately with access to quality feedback on my work and explanations for the notes in my school texts. It was unimaginably easy to share not only ideas but resources compared with the groups my father frequented. I suspect there are more amateur Hellenists than broken-laser-pointer collectors online, but probably not very many. The internet was made for us.
A journey of a thousand miles begins, obviously, with a single step. But isn’t it equally obvious that a step of a single metre must begin with a single millimetre? And before you can begin the last micron of that millimetre, don’t you have to get through 999 other microns first? And so ad infinitum? That “ad infinitum” bit is what worried the philosopher Zeno of Elea. Can our every action really consist of sub-actions each consisting of sub-sub-actions … so that before we can move at all, we have to perform a literally infinite number of distinct, consecutive actions?
Zeno’s paradox is the earliest known critique of the common-sense idea that we live in a “continuum” — an infinitely divisible, smoothly structured space. It highlights one of several awkward problems with that concept, which would be considered fatal flaws if there were a reasonable alternative. But the only alternative is that space is not infinitely divisible but discrete, and the flaw in that is a killer too: if there are only finitely many points — actions, changes, or whatever — between one place and another, how can you ever get from one to the next? There is, by definition, nothing in between, nowhere to be while you cross the gap. You start having not yet crossed; then you have crossed. Period.
This dilemma kept coming up in various guises: does matter consist of atoms? how many angels can stand on the head of a pin? In the nineteenth century the continuum seemed to have won, with the triumph of the wave theory of light — though Darwin knew that there was a problem with evolution if, as he thought, inherited traits are continuously variable. He needn’t have worried. When Max Planck solved the black body problem by postulating that atoms could absorb or emit energy only in discrete amounts, the quantum age began. The idea of quantization — the discreteness of physical quantities — turned out to be immensely fruitful. Niels Bohr used it to construct the first successful model of the internal structure of atoms. Albert Einstein used it to analyse the photoelectric effect. However, escaping from the infinities of continuous motion again raised the question “how do you get from A to B?” Modern quantum theory gives an answer of sorts. Remarkably, it describes a reality in which observable quantities do indeed take discrete values, yet motion and change are nevertheless continuous.
How can that be? Regrettably, the standard answer taught to subsequent generations of physics students was nonsense: “It’s a particle and a wave — discrete and continuous — simultaneously”. Or: “It isn’t really localised or spread out until you see the result of your experiment”. The fact that scientists could take such positions — and students accept them — marks an embarrassing period in the history of physics. A resolution compelling enough to satisfy Zeno is not yet available, but quantum theory brings us substantially closer. I believe that the resolution depends on an implication of quantum theory yet to be widely accepted: the existence of parallel universes. In short, within each universe all observable quantities are discrete, but the multiverse as a whole is a continuum. When the equations of quantum theory describe a continuous but not-directly-observable transition between two values of a discrete quantity, what they are telling us is that the transition does not take place entirely within one universe. So perhaps the price of continuous motion is not an infinity of consecutive actions, but an infinity of concurrent actions taking place across the multiverse. A kind of progress, surely.
Nowadays we rely on quantum theory to explain every last counter-intuitive nuance of the behaviour of matter at atomic scales. One of the objectives in my own field is to build quantum computers — devices that will be capable of qualitatively new types of information processing. Only the very simplest have been built so far: quantum cryptographic devices whose security depends not, as all current systems do, on transient assumptions about how much computer power or mathematical ingenuity is available to potential eavesdroppers, but on the timeless laws of quantum mechanics. It will probably be decades before even more spectacular applications, such as cracking the best existing cryptographic systems, become feasible. It is an extremely challenging task. Many different technologies have been proposed. Some doubt that it can be done, but no one seriously disputes that if these computers can be built, they will possess those capabilities. For the predictions of quantum theory are superbly corroborated in every known test. In 1900, Max Planck wasn’t sure what he had discovered. He didn’t like it, but he knew that somehow it had to contain the explanation for the observed phenomena — so he ran with it. He was right. Later generations discovered what it meant; and the longer we live with it, the more sense it makes.
“When abundant matter is ready, when space is to hand, and no thing and no cause hinders, things must assuredly be done and completed. And if there is at this moment both so great store of seeds as all the time of living existence could not suffice to tell, and if the same power and the same nature abides, able to throw the seeds of things together in any place in the same way as they have been thrown together into this place, then you are bound to confess that there are other worlds in other regions and different races of men and generations of wild beasts.”—
Lucretius DRN 2.1067-1076
All things not prevented by the laws of physics “must assuredly be done and completed.”