Freeman Dyson

The laws of nature are constructed in such a way as to make the universe as interesting as possible.

Thirty-one years ago, Dick Feynman told me about his "sum over histories" version of quantum mechanics. "The electron does anything it likes," he said. "It just goes in any direction at any speed, forward or backward in time, however it likes, and then you add up the amplitudes and it gives you the wave-function." I said to him, "You're crazy." But he wasn't.

All the books that I have seen about the science and the economics of global warming, including the two books under review, miss the main point. The main point is religious rather than scientific. There is a worldwide secular religion which we may call environmentalism, holding that we are stewards of the earth, that despoiling the planet with waste products of our luxurious living is a sin, and that the path of righteousness is to live as frugally as possible. ... Environmentalism has replaced socialism as the leading secular religion.

To talk about the end of science is just as foolish as to talk about the end of religion. Science and religion are both still close to their beginnings, with no ends in sight. Science and religion are both destined to grow and change in the millennia that lie ahead of us, perhaps solving some old mysteries, certainly discovering new mysteries of which we yet have no inkling.

The great question for our time is, how to make sure that the continuing scientific revolution brings benefits to everybody rather than widening the gap between rich and poor. To lift up poor countries, and poor people in rich countries, from poverty, to give them a chance of a decent life, technology is not enough. Technology must be guided and driven by ethics if it is to do more than provide new toys for the rich.

I have felt it myself. The glitter of nuclear weapons. It is irresistible if you come to them as a scientist. To feel it's there in your hands, to release this energy that fuels the stars, to let it do your bidding. To perform these miracles, to lift a million tons of rock into the sky. It is something that gives people an illusion of illimitable power, and it is, in some ways, responsible for all our troubles — this, what you might call technical arrogance, that overcomes people when they see what they can do with their minds.

You'll have received an application from Mr Freeman Dyson to come to work with you as a graduate student. I hope that you will accept him. Although he is only 23 he is in my view the best mathematician in England.

As we look out into the Universe and identify the many accidents of physics and astronomy that have worked together to our benefit, it almost seems as if the Universe must in some sense have known that we were coming.

I am neither a saint nor a theologian. To me, good works are more important than theology. We all know that religion has been historically, and still is today, a cause of great evil as well as great good in human affairs. We have seen terrible wars and terrible persecutions conducted in the name of religion. We have also seen large numbers of people inspired by religion to lives of heroic virtue, bringing education and medical care to the poor, helping to abolish slavery and spread peace among nations. Religion amplifies the good and evil tendencies of individual souls.

There is a great satisfaction in building good tools for other people to use.

The progress of science requires the growth of understanding in both directions, downward from the whole to the parts and upward from the parts to the whole. A reductionist philosophy, arbitrarily proclaiming that the growth of understanding must go only in one direction, makes no scientific sense. Indeed, dogmatic philosophical beliefs of any kind have no place in science.

God is what mind becomes when it has passed beyond the scale of our comprehension.

Our grey technology of machines and computers will not disappear, but green technology will be moving ahead even faster. Green technology can be cleaner, more flexible and less wasteful, than our existing chemical industries. A great variety of manufactured objects could be grown instead of made. Green technology could supply human needs with far less damage to the natural environment. And green technology could be a great equalizer, bringing wealth to the tropical areas of the world which have most of the sunshine, most of the human population, and most of the poverty. I am saying that green technology could do all these good things, bringing wealth to the tropics, bringing economic opportunity to the villages, narrowing the gap between rich and poor. I am not saying that green technology will do all these good things. "Could" is not the same as "will". To make these good things happen, we need not only the new technology but the political and economic conditions that will give people all over the world a chance to use it. To make these things happen, we need a powerful push from ethics. We need a consensus of public opinion around the world that the existing gross inequalities in the distribution of wealth are intolerable. In reaching such a consensus, religions must play an essential role. Neither technology alone nor religion alone is powerful enough to bring social justice to human societies, but technology and religion working together might do the job.

If we had a reliable way to label our toys good and bad, it would be easy to regulate technology wisely. But we can rarely see far enough ahead to know which road leads to damnation. Whoever concerns himself with big technology, either to push it forward or to stop it, is gambling in human lives.

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 important technologies, hay emerged anonymously during the so-called Dark Ages. According to the Hay Theory of History, the invention of hay was the decisive event which moved the center of gravity of urban civilization from the Mediterranean basin to Northern and Western Europe. The Roman Empire did not need hay because in a Mediterranean climate the grass grows well enough in winter for animals to graze. North of the Alps, great cities dependent on horses and oxen for motive power could not exist without hay. So it was hay that allowed populations to grow and civilizations to flourish among the forests of Northern Europe. Hay moved the greatness of Rome to Paris and London, and later to Berlin and Moscow and New York.

The gospel of St. Matthew told of the angry Jesus driving the merchants and money-changers out of the temple, knocking over the tables of the money-changers and spilling their coins on the floor. Jesus was not opposed to capitalism and the profit motive, so long as economic activities were carried on outside the temple. In the parable of the talents, he praises the servant who used his master's money to make a profitable investment, and condemns the servant who was too timid to invest. But he draws a clear line at the temple door. Inside the temple, the ground belongs to God and profit-making must stop.

The bottom line for mathematicians is that the architecture has to be right. In all the mathematics that I did, the essential point was to find the right architecture. It's like building a bridge. Once the main lines of the structure are right, then the details miraculously fit. The problem is the overall design.

I have five minutes left to give you a message to take home. The message is simple. "God forbid that we should give out a dream of our own imagination for a pattern of the world". This was said by Francis Bacon, one of the founding fathers of modern science, almost four hundred years ago. Bacon was the smartest man of his time, with the possible exception of William Shakespeare.

Science and religion are two windows that people look through, trying to understand the big universe outside, trying to understand why we are here. The two windows give different views, but they look out at the same universe. Both views are one-sided, neither is complete. Both leave out essential features of the real world. And both are worthy of respect.

In the little town of Princeton where I live, we have more than twenty churches and at least one synagogue, providing different forms of worship and belief for different kinds of people. They do more than any other organizations in the town to hold the community together. Within this community of people, held together by religious traditions of human brotherhood and sharing of burdens, a smaller community of professional scientists also flourishes.