The Importance of Hay

The technologies which have had the most profound effects on human life are usually simple. A good example of a simple technology with profound historical consequences is hay. Nobody knows who invented hay, the idea of cutting grass in the autumn and storing it in large enough quantities to keep horses and cows alive through the winter. All we know is that the technology of hay was unknown to the Roman Empire but was known to every village of medieval Europe. Like many other crucially importa...

 "Infinite in All Directions," Meaning of the Title

The title is now changed so as to focus more sharply upon the message I am preaching. Boiled down to one sentence, my message is the unbounded prodigality of life and the consequent unboundedness of human destiny. As a working hypothesis to explain the riddle of our existence, I propose that our universe is the most interesting of all possible universes, and our fate as human beings is to make it so.

 Religion and Science are Alike

When I talk about religion, I speak for myself alone. Any statement which attempted to express a consensus of scientists about religious and philosophical questions would miss the main point. There is no consensus among us. The voice of science is a Babel of diverse languages and cultures. That is to me the joy and charm of science. Science is a free creation of the human mind, and at the same time it is an international club cutting across barriers of race and nationality and creed. Many fir...

 Humanity is Not the Purpose of the Universe, It is Humani...

Another phrase which occurs frequently in the propaganda of Christian fundamentalists is "scientific humanism." Scientific humanism is supposed to be a philosophy standing in opposition to Christian faith. Fundamentalists like to pretend that we have only two alternatives, either scientific humanism or their version of Christianity. But scientific humanism has as many different meanings as scientific materialism. Roughly speaking, a scientific humanist is somebody who believes in science and ...

 The Need for Diversity and Empathy in Science and Religion

The diversity of science also finds a parallel in the diversity of religion. Once, when I was a child, walking with my mother through the English cathedral town of Winchester, I asked her: "Why are there so many different churches?" My mother gave me a wise answer: "Because God likes it that way. If he had wanted us all to worship him in one church, he would not have made so many different kinds of people." That was an answer invented on the spur of the moment to satisfy the curiosity of a fi...

 Superstring Theory

It is time now to try to describe what a superstring really is. Here I run into the same difficulty which the geometer Euclid encountered 2,200 years ago. Euclid was trying to convey to his readers his idea of a geometrical point. For this purpose he gave his famous definition of a point: "A point is that which has no parts, or which has no magnitude." This definition would not be very helpful to somebody who was ignorant of geometry and wanted to understand what a point was. Euclid's notion ...

 A Black Hole is a Star Forever Falling Inward

He talked to us about the new theory of black holes which he had then just worked out. The idea of a black hole was one of the most dramatic consequences of Einstein's theory of gravity. According to Einstein's equations, a massive star at the end of its life, when it has exhausted its nuclear fuel, continues to contract and grow smaller and denser under the influence of its own gravitation. After the nuclear fuel is used up, the star goes into a state of gravitational collapse. All parts of ...

 Plank's Constant

In the year 1900 Max Planck wrote down an equation, E = hv, where E is the energy of a light wave, v is its frequency, and h is a constant which we now call Planck's constant. Planck's equation was the beginning of quantum theory. It said that energy and {22} frequency are the same thing measured in different units. Energy is measured in ergs and frequency in cycles. Planck's constant gives you the rate of exchange for converting frequency into energy, namely, 6 × 10–27 ergs per cycle. But ...

 Hawking's Equation

awking has written down an equation which looks rather like Planck's equation. Hawking's equation is S = kA, where S is the entropy of a black hole, A is the area of its surface, and k is a constant which I call Hawking's constant. Entropy means roughly the same thing as the heat capacity of an object. It is measured in units of calories per degree. A is measured in square centimeters. Hawking's equation says that entropy is really the same thing as area. The exchange rate between area and en...

 Shotgun Seminar

At our Institute in Princeton we sometimes organize meetings which are announced as Shotgun Seminars. A Shotgun Seminar is a talk given by an Institute member to a volunteer audience. The subject of the talk is announced a week in advance, but the name of the speaker is not. Before the talk begins, the names of all people in the room are written on scraps of paper, the scraps are put into a box, the box is ceremoniously shaken and one name is picked out at random. The name picked out is the n...

 The Comet Loss Cone

To understand why comet showers occur, we go back to the Oort Cloud. The theory of comet showers was worked out by Jack Hills, an American physicist now at Los Alamos. He realized that the movements of the comets in the Oort Cloud are not entirely random. Comets in the cloud are generally moving in random directions, but if a comet happens to be moving in an orbit almost exactly toward the Sun, it will not survive for long. A comet in an orbit coming close to the Sun may get boiled away and d...

 Nemisis

Piet Hut, another Dutch astronomer fifty years younger than Jan Oort, decided to take seriously the possibility that comet showers are periodic. If they are periodic, the theory that they are caused by the random passing-by of alien stars cannot be right. If showers are periodic, they must be explained by a different theory. Piet Hut and his friend Rich Muller found an alternative theory to explain the periodicity in case it turns out to be real. The alternative theory is called Nemesis. Neme...

 Astronomers Inventing Planets Based on Circumstantial Evi...

It happened three times in the past that theoretical astronomers invented a new planet on the basis of indirect and circumstantial evidence. The first time was in 1845 when Adams and Leverrier independently deduced the existence of the planet Neptune from the perturbations which it had produced in the motion of Uranus. One year later, Neptune was duly discovered in the predicted region of the sky. The successful prediction of the presence of an unseen planet was one {31} of the great events...

 Manchester and the Birth of the Industrial Revolution

What was so exciting about Manchester? Disraeli with his acute political and historical instinct understood that Manchester had done something unique and revolutionary. Only he was wrong to call it science. What Manchester had done was to invent the Industrial Revolution, a new style of life and work which began in that little country town about two hundred years ago and inexorably grew and spread out from there until it had turned the whole world upside down. Disraeli was the first politicia...

 Broken Symmetry

The discoveries of recent decades in particle physics have led us to place great emphasis on the concept of broken symmetry. The development of the universe from its earliest beginnings is regarded as a succession of symmetry-breakings. As it emerges from the moment of creation in the Big Bang, the universe is completely symmetrical and featureless. As it cools to lower and lower temperatures, it breaks one symmetry after another, allowing more and more diversity of structure to come into exi...

 Science Unifiers

Now it is generally true that the very greatest scientists in each discipline are unifiers. This is especially true in physics. Newton and Einstein were supreme as unifiers. The great triumphs of physics have been triumphs of unification. We almost take it for granted that the road of progress in physics will be a wider and wider unification bringing more and more phenomena within the scope of a few fundamental principles. Einstein was so confident of the correctness of this road of unificati...

 Science Communication: Definitions VS Metaphors

A hundred years ago, Charles Darwin could write books discussing the central problems of biology in language which was scientifically precise and still accessible to the general public. In those days the subject matter of biology was plants and animals. The language of Darwin was intelligible to experts and non-experts alike. One did not need a degree in {55} botany to understand the difference between a fern and a flower. Darwin could assume that his readers were familiar with the world of...

 Computer Metaphors for Biochemistry

The metaphor of the computer represents in some crude fashion the chemistry of life. Nowadays one may assume that the average citizen of an industrialized country is at least as familiar with computers as with rain forests. The idea of using the computer as a metaphor is a natural one. A computer is a device for handling information according to a program which it is able to remember and execute. A living cell, to remain in control of its vital functions in a variable environment, must also p...

 Life with Metabolism VS Replication

It is logically possible to postulate organisms composed of pure hardware, capable of metabolism but incapable of replication. It is possible to postulate organisms composed of pure software, capable of replication but incapable of metabolism. And if the functions of life are separated in this fashion, it is to be expected that the latter type of organism will become an obligatory parasite upon the former. This logical analysis of the functions of life helps to explain and to correct the bias...

 Genetic Drift is More Important than Natural Selection

[Motoo Kimura] has been the chief advocate of the neutral theory of evolution. The neutral theory says that, through the history of life from beginning to end, random statistical fluctuations have been more important than Darwinian selection in causing species to evolve. Evolution by random statistical fluctuation is called genetic drift. Kimura says that genetic drift drives evolution more powerfully than natural selection.

 Error Catastrophe

The central problem for any theory of the origin of replication is the fact that a replicative apparatus has to function almost perfectly if it is to function at all. If it does not function perfectly, it will give rise to errors in replicating itself, and the errors will accumulate from generation to generation. The accumulation of errors will result in a progressive deterioration of the system until it is totally disorganized. This deterioration of the replicative apparatus is called the "e...

 Tangled Bank of the Primeval Cell

In our present state of ignorance, we have a choice between two contrasting images to represent our view of the possible structure of a creature newly emerged at the first threshold of life. One image is the replicator model of Eigen, a molecular structure tightly linked and centrally controlled, replicating itself with considerable precision, achieving ho-meostasis by strict adherence to a rigid pattern. The other image is the "tangled bank" of Darwin, an image which Darwin put at the end of...

 Tyranny of the Gene Tempered by Junk DNA

The analogies between the genetic evolution of biological species and the cultural evolution of human societies have been brilliantly explored by Richard Dawkins in his book The Selfish Gene. The book is mainly concerned with biological evolution; the cultural analogies are only pursued in the last chapter. Dawkins's main theme is the tyranny which the rigid demands of the replication apparatus have imposed upon all biological species throughout evolutionary history. Every species is the pris...

 Darwin and the Origins of Life

There is a curious parallelism between Darwin's twenty-year delay in publishing his theory of evolution and Newton's {102} twenty-year delay in publishing the Principia. And Newton's refusal to publish his cosmological speculations finds a parallel in Darwin's silence concerning the problem of the origin of life. If we are to understand in general terms the place of life in the universe, we must also understand life's origin. Darwin explicitly excluded the origin of life from the scope of ...

 Q

The hypothesis of {108} abstraction says that every living creature is characterized by a number Q which is a measure of the complexity of the creature. To measure Q, we do not need to know anything about the internal structure of the creature. Q can be measured by observing from the outside the behavior of the creature and its interaction with its environment. Q is simply the quantity of entropy produced by the creature's metabolism during the time it takes to perform an elementary respons...

 Life Favors a Cold, Expanding Universe

If, on the other hand, we live in an open universe, infinite in space and time and continuing to expand into a future without end, then life has to face a prospect of slow freezing {111} rather than quick frying. The universe grows constantly colder as it expands, and the supply of free energy is constantly dwindling. To many people this future of endless ice has seemed even more dismal than the future of cataclysmic fire. But the laws of cosmic ecology put these futures into a very differe...

 Energy Needed to Power Civilization

The numerical results of my calculations show that the quantities of energy required for permanent survival and communication are surprisingly modest. For a society with the same complexity as the present human society on Earth, starting from the present time and continuing forever, the total reserve of energy required is about equal to the energy now radiated by the Sun in eight hours. The total energy reserve contained in the Sun would be sufficient to support forever a society with a compl...

 The Mind

To me the most astounding fact in the universe, even more astounding than the flight of the Monarch butterfly, is the power of mind which drives my fingers as I write these words. Somehow, by natural processes still totally mysterious, a million butterfly brains working together in a human skull have the power to dream, to calculate, to see and to hear, to speak and to listen, to translate thoughts and feelings into marks on paper which other brains can interpret. Mind, through the long cours...

 Preachers and Prophets

Since I have had to pay college tuition for five daughters, I have chosen to play the role of preacher. I preach to all who will listen the gospel of manifest destiny. The destiny which I am preaching is not the expansion of a single nation or of a single species, but the spreading out of life in all its multifarious {134} forms from its confinement on the surface of our small planet to the freedom of a boundless universe. This unimaginably great and diverse universe, in which we occupy one...

 The Unspecialized Will Inherit the Earth

Why is it that our whole economic and political system has tended recently to become so sluggish and inflexible? Why have we become resigned to the idea that nothing substantial can ever be done in less than ten years? Obviously there are many reasons. But I believe the principal reason for this sluggishness is that our whole society has fallen into the same trap as our nuclear industry. Not only in the nuclear industry but in many other industries and public institutions, we have pursued eco...

 Science Fiction Genetic Engineering

It is difficult to speak of specific examples of things genetic engineering may do for us. Specific examples always sound like stories out of Astounding Science Fiction magazine. Here are three long-range possibilities. First, the energy tree, programmed to convert the products of photosynthesis into conveniently harvested liquid fuels instead of cellulose. Second, the mining worm, a creature like an earthworm, programmed to dig into any kind of clay or metalliferous ore and bring to the surf...

 Economic Forecasting VS Science Fiction Predictions

There are two ways to predict the progress of technology. One way is economic forecasting, the other way is science fiction. Economic forecasting makes predictions by extrapolating curves of growth from the past into the future. Science fiction makes a wild guess and leaves the judgment of its plausibility to the reader. Economic forecasting is useful for predicting the future up to about ten years ahead. Beyond ten years it rapidly becomes meaningless. Beyond ten years the quantitative chang...

 Von Neuman and Predicting the Weather

I remember a talk that Von Neumann gave at Princeton around 1950, describing the glorious future which he then saw for his computers. Most of the people that he hired for his computer project in the early days were meteorologists. Meteorology was the big thing on his horizon. He said, as soon as we have good computers, we shall be able to divide the phenomena of meteorology cleanly into two categories, the stable and the unstable. The unstable phenomena are those which are upset by small dist...

 The Soviet Union, Von Neuman Predictions, and Computers

I have a friend, a young American physicist, who spent a year doing theoretical physics in the Soviet Union. He likes to go to the Soviet Union, not because it is a good place to do physics, but because it is a good place to observe the human comedy. When he went back to Leningrad recently for a shorter visit, he received a proposal of marriage and was called in twice for questioning by the KGB, all within the first week. He speaks fluent Russian, and the KGB people find it difficult to belie...

 Astrochicken

The basic idea of Astrochicken is that the spacecraft will be small and quick. I do not believe that a fruitful future for space science lies along the path we are now following, with space missions growing larger and larger and fewer and fewer and slower and slower as the decades go by. I propose a radical step in the direction of smallness and quickness. Astrochicken will weigh a kilogram instead of Voyager's ton, and it will travel from Earth into orbit around Uranus in two years instead ...

 War is the Price of Diversity

The state of the world today is not essentially different from the state of the world in 1948. We are still faced with the same choices that we were facing in 1948. On the level of fundamental principles, we are faced with a choice between unity and diversity. The unity of mankind, or the diversity of nations and political institutions. National sovereignty is the contemporary expression of the ancient human tradition which divided us into {202} tribes, each jealously guarding its independe...

 Success of America is Due to Hamilton's Jaundiced View of...

The practical success and durability of the Constitution owe much to Hamilton's jaundiced view of human nature. The American Constitution is designed to be operated by crooks, just as the British constitution is designed to be operated by gentlemen. Because Hamilton believed that men are by nature crooks rather than gentlemen, he was able to help design a constitution that could deal effectively with President Nixon. If ever a World Government should come into existence, it had better be a go...

 Resistance to World Government

The case for World Government as Hamilton and Einstein presented it is logically compelling. Fortunately or unfortunately, World Government has a fatal defect. Nobody wants it. At the time when Einstein preached World Government most seriously, he was bitterly attacked by Soviet scientific colleagues as well as by patriotic American politicians. "By the irony of fate," the Soviet scientists proclaimed, "Einstein has virtually become a supporter of the schemes and ambitions of the bitterest fo...

 Dyson VS Sagan on Nuclear Winter

I do not wish here to get into a technical argument about the details of nuclear winter. I will merely summarize my own struggles with the technical issues. I spent a few weeks in 1985 trying to make nuclear winter go away. The phrase "go away" here is used in the sense customary among scientists. To destroy a new theory, you try to find a simple situation where the theory predicts that something happens and you can prove that the same something does not happen. Then you say that the thing pr...

 Technology is Information

The most revolutionary aspect of technology is its mobility. Anybody can learn it. It jumps easily over barriers of race and language. And its mobility is still increasing. The new technology of microchips and computer software is learned much faster than the old technology of coal and iron. It took three generations of misery for the older industrial countries to master the technology of coal and iron. The new industrial countries of East Asia, South Korea and Singapore and Taiwan, mastered ...

 Three Types of Artificial Intelligence

Lighthill begins by dividing artificial intelligence into three areas which he calls A, B, and C. A stands for advanced automation, the objective being to replace human beings by machines for specific purposes, for example, industrial assembly, military reconnaissance or scientific analysis. A large body of work in category A is concerned with pattern recognition, with the programming of computers to read documents or to recognize spoken words. C stands for computer-based central-nervous-syst...

 Profiting on Asteroids

Some of the first questions which come up in any practical discussion of space colonization are questions of economics. Suppose we go out and settle on a convenient asteroid with our little spaceship, what do we do when we get there? How do we make a living? What can we expect to export in order to pay for necessary imports? If space colonization makes any sense at all, these questions must have sensible answers. Unfortunately, we cannot hope to answer questions of economics until the asteroi...

 Steps to Colonizing Space

The third technological revolution which I see coming is the expansion of life's habitat from Earth into the solar system and beyond. This revolution may take a little longer than the other two. Perhaps it may take as long as a hundred years from now. In charting a possible course for this revolution, I take as my guide Ben Finney, an anthropologist at the University of Hawaii who has made a detailed study of the Polynesian navigators and their voyages of colonization from island to island ac...

 Elements of Humanity's Future

The next hundred years will be a period of transition between the metal-and-silicon technology of today and the enzyme-and-nerve technology of tomorrow. The enzyme-and-nerve technology will be the result of combining the tools of genetic engineering and artificial intelligence. We cannot hope to predict the concrete forms in which a mature enzyme-and-nerve technology would express itself. When I think of the space technology of tomorrow, I think of three concrete images in particular. First, ...

 H.G. Wells Time Machine and Evolution

Nobody has imagined the future of fate with greater artistry than H. G. Wells in his fantasy The Time Machine, published in 1895. Wells imagined the human species split in two, the spark of reason dulled and the sense of purpose extinguished. His two species, the degenerate descendants of the upper and lower classes of Victorian England, are caught in an evolutionary dead end without hope of escape. The lower class, living underground like rats, has retained enough manual dexterity to keep th...

 Diversification in the Cosmos

The last of the five philosophical problems is the problem of final aims. The problem here is to try to formulate some {298} statement of the ultimate purpose of the universe. In other words, the problem is to read God's mind. Previous attempts to read God's mind have not been notably successful. One of the more penetrating of such attempts is recorded in the Book of Job. God's answer to Job out of the whirlwind was not encouraging. Nevertheless I stand in good company when I ask again the ...

 Warm-Blooded Plants: Zero-g, Zero-T, and Zero-P

There are three principal obstacles to be overcome in adapting a terrestrial species to life in space. It must learn to live and be happy in zero-g, zero-T, and zero-P, that is to say, zero-gravity, zero-temperature, and zero-pressure. Of these, zero-g is probably the easiest to cope with, although we are still ignorant of the nature of the physiological hazards which it imposes. To deal with zero-T is simple in principle although it may be complicated and awkward in practice. Fur and feather...

 The Dilemma of Human Diversity Across the Cosmos

When life spreads out and diversifies in the universe, adapting itself to a spectrum of environments far wider than any one planet can encompass, the human species will one day find itself faced with the most momentous choice that we have had to make since the days when our ancestors came down from the trees in Africa and left their cousins the chimpanzees behind. We will have to choose, either to remain one species united by a common bodily shape as well as by a common history, or to let our...

 Technology is Preserving Our Ghosts

Our technology is giving us progressively greater power to keep alive our ancestors' ghosts. First the invention of writing allowed us to preserve their words. Painting and photography allowed us to preserve their faces. The phonograph preserves their voices and the videotape recorder preserves their movement and gestures. But this is only the beginning. Soon we shall acquire the technology to preserve a permanent record of the sequence of bases in the DNA of their cells. This means that we s...

 Intellectual Exploration as Geographical Exploration

My own field of physics is passing today through a phase of exuberant freedom, a phase of passionate prodigality. Sometimes as I listen to the conversation of my young colleagues at Princeton, I feel as if I am lost in a rain forest, with insects and birds and flowers growing all around me in intricate profusion, growing too abundantly for my sixty-year-old brain to comprehend. But the young people are at home in the rain forest and walk confidently along trails which to me are almost invisib...