THE ASCENT OF MAN

 JACOB BROWNOWSKI

MACDONALD FUTURA PUBLISHERS                        1973

PART VII

 

Chapter 7: The Majestic Clockwork

By the year 1650, the center of gravity of the civilized world had shifted from Italy to Northern Europe. The obvious reason is that the trade routes of the world were different since the discovery and exploitation of America. No longer was the Mediterranean what its name implies, the middle of the world. The middle of the world had shifted north as Galileo had warned, to the fringe of the Atlantic. And with a different trade came a different political outlook, while Italy and the Mediterranean were still ruled by autocracies.

• New ideas and new principles now moved forward in the Protestant seafaring nations of the north, England and the Netherlands.
• The two years after Newton graduated at Cambridge, 1665 and 1666, were years of Plague, spent at home. From his notebooks it is clear that he had not been well taught, and that he proved most of the mathematics he knew for himself.
• He invented fluxions, what we now call the calculus, discovering his results with it but writing them out in conventional mathematics. He conceived the idea of universal gravitation and calculated the motion of the moon around the earth to be 27¼ days.
• When the figures come out right like that, you know as Pythagoras did, that a secret of nature is open in the palm of your hand.
• It is odd to find that a man whom we regard as the master of explanation of the material universe should have begun with light. We see matter by light; we are aware of the presence of light by the interruption by matter. That thought makes up the world of every great physicist, who finds that he cannot deepen his understanding of one without the other.
• By the time Newton was in his 70s, little real scientific work was done in the Royal Society. England was preoccupied with money (these are the years of the South Sea Bubble), with politics, and with scandal. Nimble businessmen floated companies to exploit fictitious inventions.
• Time is the other absolute in Newton’s system, crucial for mapping the heavens. The mariner’s world called for two sets of instruments: telescopes and clocks.
• The universe of Newton ticked on without a hitch for 200 years, until, just after 1900, Einstein asked what our experience would look like seen from the point of view of light.
• The genius of men like Newton and Einstein is that they ask transparent, innocent questions which turn out to have catastrophic answers.

I go to the bottom of the clocktower, and get into the tram he used to take every day on his way to work as a clerk in the Swiss Patent Office.

The thought that Einstein had had in his teens was this: ‘What would the world look like if I rode on a beam of light?’ Suppose this tram were moving away from that clock on the very beam with which we see what the clock says. Then, of course, the clock would be frozen. I, the tram, this box riding on the beam of light would be fixed in time. Time would have a stop.

Let me spell that out. Suppose the clock behind me says ‘noon’ when I leave. I now travel 186,000 miles away from it at the speed of light; that ought to take me one second. But the time on the clock, as I see it, still says ‘noon’, because it takes the beam of light from the clock exactly as long as it has taken me. So far as the clock as I see it, so far as the universe inside the tram is concerned, in keeping up with the speed of light I have cut myself off from the passage of time.

• If I rode on a beam of light, time would suddenly come to an end for me. And that must mean that, as I approach the speed of light (which is what I am going to simulate in this tram), I am alone in my box of time and space, which is more and more departing from the norms round me.

Such paradoxes make two things clear. An obvious one: there is no universal time. But a more subtle one: that experience runs very differently for the traveller and the stay-at-home – and so for each of us on his own path. My experiences within the tram are consistent: I discover the same laws, the same relations between time, distance, speed, mass and force, that every other observer discovers. But the actual values that I get for time, distance, and so on, are not the same that the man on the pavement gets.

That is the core of the Principle of Relativity. But the obvious question is ‘Well, what holds his box and mine together?’ The passage of light: light is the carrier of information that binds us. And that is why the crucial experimental fact is the one that puzzled people since 1881: that when we exchange signals, then we discover that information passes between us always at the same pace. We always get the same value for the speed of light. And then naturally time and space and mass must be different for each of us, because they have to give the same laws for me here in the tram and for the man outside, consistently – yet the same value for the speed of light.

We will take the tram up towards the speed of light to see what the appearances look like. The relativity effect is that things change shape. (There are also changes in colour, but they are not due to relativity.) The tops of the buildings seem to bend inwards and forwards. The buildings also seem crowded together. I am traveling horizontally, so horizontal distances seem shorter; but the heights remain the same. Cars and people are distorted in the same way: thin and tall. And what is true for me looking out is true for the man outside looking in. The Alice in Wonderland world of relativity is symmetrical.

Evidently this is an altogether different picture of the world from that which Newton had. For Newton, time and space formed an absolute framework, within which the material events of the world ran their course in imperturbable order. His is a God’s eye view of the world: it looks the same to every observer, wherever he is and however he travels. By contrast, Einstein’s is a man’s eye view, in which what you see and what I see is relative to each of us, that is, to our place and speed. And this relativity cannot be removed. We cannot know what the world is like in itself, we can only compare what it looks like to each of us, by the practical procedure of exchanging messages. I in my tram and you reading this can share no divine and instant view of events – we can only communicate our own views to one another. And communication is not instant; we cannot remove from it the basic time-lag of all signals, which is set by the speed of light.

• Einstein was a man who thought for himself, going to the heart of the question ‘How do human beings communicate with one another? How do we reach knowledge?’ And that is the crux of all his papers, this unfolding of the heart of knowledge, almost petal by petal.
• The great paper of 1905 is not just about light or, as the title says, The Electrodynamics of Moving Bodies, but simply a part of drawing the world together, coming from a profound insight into the relations between man, knowledge, and nature.
• Einstein died in 1955 when time could be measured to a thousand millionth of a second. It was possible to look at the odd proposal to ‘think of two men on earth, one at the North Pole and one at the Equator. The one at the Equator is going round faster than the one at the North Pole; therefore his watch will lose’. And that is just how it turned out.
• Einstein had a genius for finding philosophical ideas that gave a new view of practical experience. He did not look at nature like a God but like a pathfinder, a man inside the chaos of her phenomena who believed that there is a common pattern visible in them all if we look with fresh eyes.
• In a lifetime Einstein joined light to time, and time to space; energy to matter, matter to space, and space to gravitation. At the end of his life he was still seeking a unity between gravitation and the forces of electricity and magnetism.
• And that is how I remember him, lecturing in the Senate House at Cambridge in an old sweater and carpet slippers with no socks, to tell us what kind of a link he was trying to find there, and what difficulties he was running his head against.
• He was quite unconcerned about worldly success, or respectability, or conformity. He hated war, cruelty, and hypocrisy, and above all he hated dogma.
• It is almost impertinent to talk of the ascent of man in the presence of two men, Newton and Einstein, who stride like Gods. Newton is the Old Testament God while Einstein is the New Testament figure. He was full of humanity, pity, a sense of enormous sympathy.
• His vision of nature herself was that of a man being in the presence of something god-like. ‘God does not play dice. God is not malicious.’ Einstein was a man who could ask immensely simple questions. And what his life showed, and his work, is that when the answers are simple too, then you hear God thinking.

 

Chapter 8: The Drive for Power