January 8, 2002

The renowned physicist Stephen Hawking speculates on the future of the human race

THE reason Star Trek is so popular is because it is a safe and comforting vision of the future. I’m a bit of a Star Trek fan myself, so I was easily persuaded to take part in an episode in which I played poker with Newton, Einstein, and Commander Data. I beat them all, but unfortunately there was a red alert, so I never collected my winnings.

Star Trek shows a society that is far in advance of ours in science, in technology, and in political organization. (The last might not be difficult.) There must have been great changes, with their accompanying tensions and upsets, in the time between now and then, but in the period we are shown, science, technology, and the organization of society are supposed to have achieved a level of near perfection.

I want to question this picture and ask if we will ever reach a final steady state in science and technology. At no time in the ten thousand years or so since the last ice age has the human race been in a state of constant knowledge and fixed technology. There have been a few setbacks, like the Dark Ages after the fall of the Roman Empire. But the world’s population, which is a measure of our technological ability to preserve life and feed ourselves, has risen steadily, with only a few hiccups such as the Black Death.

In the last 200 years, population growth has become exponential, that is, the population grows by the same percentage each year. Currently, the rate is about 1.9 per cent a year. That may not sound like very much, but it means that the world population doubles every forty years.

Other measures of technological development in recent times are electricity consumption and the number of scientific articles. They too show exponential growth, with doubling times of less than forty years. There is no sign that scientific and technological development will slow down and stop in the near future — certainly not by the time of Star Trek, which is supposed to be not that far in the future. But if the population growth and the increase in the consumption of electricity continue at their current rates, by 2600 the world’s population will be standing shoulder to shoulder, and electricity use will make the Earth glow red-hot.

If you stacked all the new books being published next to each other, you would have to move at ninety miles an hour just to keep up with the end of the line. Of course, by 2600 new artistic and scientific work will come in electronic forms, rather than as physical books and papers. Nevertheless, if the exponential growth continued, there would be ten papers a second in my kind of theoretical physics, and no time to read them.

Clearly, the present exponential growth cannot continue indefinitely. So what will happen? One possibility is that we will wipe ourselves out completely by some disaster, such as a nuclear war. There is a sick joke that the reason we have not been contacted by extraterrestrials is that when a civilization reaches our stage of development, it becomes unstable and destroys itself. However, I’m an optimist. I don’t believe the human race has come so far just to snuff itself out when things are getting interesting.

The Star Trek vision of the future — that we achieve an advanced but essentially static level — may come true in respect of our knowledge of the basic laws that govern the universe. There may be an ultimate theory that we will discover in the not-too-distant future. This ultimate theory, if it exists, will determine whether the Star Trek dream of warp drive can be realized. According to present ideas, we shall have to explore the galaxy in a slow and tedious manner, using spaceships travelling slower than light, but since we don’t yet have a complete unified theory, we can’t quite rule out warp drive.

On the other hand, we already know the laws that hold in all but the most extreme situations: the laws that govern the crew of the Enterprise, if not the spaceship itself. Yet it doesn’t seem that we will ever reach a steady state in the uses we make of these laws or in the complexity of the systems that we can produce with them.

By far the most complex systems that we have are our own bodies. Life seems to have originated in the primordial oceans that covered the Earth four billion years ago. How this happened we don’t know. It may be that random collisions between atoms built up macromolecules that could reproduce themselves and assemble themselves into more complicated structures. What we do know is that by three and a half billion years ago, the highly complicated DNA molecule had emerged.

DNA is the basis for all life on Earth. It has a double helix structure, like a spiral staircase, which was discovered by Francis Crick and James Watson in the Cavendish lab at Cambridge in 1953. The two strands of the double helix are linked by pairs of bases, like the treads in a spiral staircase. There are four bases in DNA: adenine, guanine, thymine, and cytosine. The order in which they occur along the spiral staircase carries the genetic information that enables the DNA to assemble an organism around it and reproduce itself. As it makes copies of itself, there are occasional errors in the proportion or order of the bases along the spiral. In most cases, the mistakes in copying make the DNA either unable or less likely to reproduce itself, meaning that such genetic errors, or mutations, as they are called, will die out. But in a few cases, the error or mutation will increase the chances of the DNA surviving and reproducing. Such changes in the genetic code will be favoured. This is how the information contained in the sequence of DNA gradually evolves and increases in complexity.

Because biological evolution is basically a random walk in the space of all genetic possibilities, it has been very slow. The complexity, or number or bits of information, that is coded in DNA is roughly the number of bases in the molecule. For the first two billion years or so, the rate of increase in complexity must have been of the order of one bit of information every hundred years. The rate of increase of DNA complexity gradually rose to about one bit a year over the last few million years. But then, about six or eight thousand years ago, a major new development occurred. We developed written language. This meant that information could be passed from one generation to the next without having to wait for the very slow process of random mutations and natural selection to code it into the DNA sequence. The amount of complexity increased enormously. A single paperback romance could hold as much information as the difference in DNA between apes and humans, and a thirty-volume encyclopaedia could describe the entire sequence of human DNA.

Even more important, the information in books can be updated rapidly. The current rate at which human DNA is being updated by biological evolution is about one bit a year. But there are two hundred thousand new books published each year, a new information rate of over a million bits a second. Of course, most of this information is garbage, but even if only one bit in a million is useful, that is still a hundred thousand times faster than biological evolution.

This transmission of data through external, nonbiological means has led the human race to dominate the world and to have an exponentially increasing population. But now we are at the beginning of a new era, in which we will be able to increase the complexity of our internal record, the DNA, without having to wait for the slow process of biological evolution. There has been no significant change in human DNA in the last ten thousand years, but it is likely that we will be able to completely redesign it in the next thousand. Of course, many people will say that genetic engineering of humans should be banned, but it is doubtful we will be able to prevent it. Genetic engineering of plants and animals will be allowed for economic reasons, and someone is bound to try it on humans. Unless we have a totalitarian world order, someone somewhere will design improved humans.

Clearly, creating improved humans will create great social and political problems with respect to unimproved humans. My intention is not to defend human genetic engineering as a desirable development, but just to say it is likely to happen whether we want it or not. This is the reason why I don’t believe science fiction like Star Trek, where people 400 years into the future are essentially the same as we are today. I think the human race, and its DNA, will increase its complexity quite rapidly. We should recognize that this is likely to happen and consider how we will deal with it.

In a way, the human race needs to improve its mental and physical qualities if it is to deal with the increasingly complex world around it and meet new challenges such as space travel. Humans also need to increase their complexity if biological systems are to keep ahead of electronic ones. At the moment, computers have the advantage of speed, but they show no sign of intelligence. This is not surprising, because our present computers are less complex than the brain of an earthworm, a species not noted for its intellectual powers.

But computers obey what is known as Moore’s law: their speed and complexity double every eighteen months. It is one of those exponential growths that clearly cannot continue indefinitely. However, it will probably continue until computers have a complexity similar to that of the human brain. Some people say that computers can never show true intelligence, whatever that may be. But it seems to me that if very complicated chemical molecules can operate in humans to make them intelligent, then equally complicated electronic circuits can also make computers act in an intelligent way. And if they are intelligent, they can presumably design computers that have even greater complexity and intelligence.

Will this increase of biological and electronic complexity go on forever, or is there a natural limit? On the biological side, the limit on human intelligence up to now has been set by the size of the brain that will pass through the birth canal. Having watched my three children being born, I know how difficult it is for the head to get out. But within the next hundred years, I expect we will be able to grow babies outside the human body, so this limitation will be removed. Ultimately, however, increases in the size of the human brain through genetic engineering will come up against the problem that the body’s’ chemical messengers responsible for our mental activity are relatively slow-moving. This means that further increases in the complexity of the brain will be at the expense of speed. We can be quick-witted or very intelligent, but not both. Still, I think we can become a lot more intelligent than most of the people in Star Trek, not that that might be difficult.

Electronic circuits have the same complexity-versus-speed problem as the human brain. In this case, however, the signals are electrical, not chemical, and travel at the speed of light, which is much higher. Nevertheless, the speed of light is already a practical limit on the design of faster computers. One can improve the situation by making the circuits smaller, but ultimately there will be a limit set by the atomic nature of matter. Still, we have some way to go before we meet that barrier.

Another way in which electronic circuits can increase their complexity while maintaining speed is to copy the human brain. The brain does not have a single CPU — central processing unit — that processes each command in sequence. Rather, it has millions of processors working together at the same time. Such massively parallel processing will be the future for electronic intelligence as well.

Assuming we don’t destroy ourselves in the next hundred years, it is likely that we will spread out first to the planets in the solar system and then to the nearby stars. But it won’t be like Star Trek or Babylon 5, with a new race of nearly human beings in almost every stellar system. The human race has been in its present form for only two million years out of the fifteen billion years or so since the big bang.

So even if life develops in other stellar systems, the chances of catching it at a recognizably human stage are very small. Any alien life we encounter will likely be either much more primitive or much more advanced. If it is more advanced, why hasn’t it spread through the galaxy and visited Earth? If aliens had come here, it should have been obvious: more like the film Independence Day than ETx.

So how does one account for our lack of extraterrestrial visitors? It could be that there is an advanced race out there which is aware of our existence but is leaving us to stew in our own primitive juices. However, it is doubtful it would be so considerate to a lower life-form: do most of us worry how many insects and earthworms we squash underfoot? A more reasonable explanation is that there is a very low probability either of life developing on other planets or of that life developing intelligence. Because we claim to be intelligent, though perhaps without much ground, we tend to see intelligence as an inevitable consequence of evolution. However, one can question that. It is not clear that intelligence has much survival value. Bacteria do very well without intelligence and will survive us if our so-called intelligence causes us to wipe ourselves out in a nuclear war. So as we explore the galaxy we may find primitive life, but we are not likely to find beings like us.

The future of science won’t be like the comforting picture painted in Star Trek: a universe populated by many humanoid races, with an advanced but essentially static science and technology. Instead, I think we will be on our own, but rapidly developing in biological and electronic complexity. Not much of this will happen in the next hundred years, which is all we can reliably predict. But by the end of the next millennium, if we get there, the difference from Star Trek will be fundamental.

 

Excerpts from

The universe in a nutshell

By Stephen Hawking

Bantam Press, London Distributed in Pakistan by Paramount Books, 152/O, Block 2, PECH Society, Karachi-75400 Tel: 021-4310030.

Email: paramount@cyber.net.pk

ISBN 0593 048156 216pp. Rs1495

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