About the answer to the first question, most of the leaders hadn't much doubt. The history of the fission bomb had made them technologically confident. What was possible in theory, had proved to be workable in practice. At first inspection, there didn't look to be quite the number of critical problems that they had had to grapple with between 1941 and 1945. (In actual fact, there turned out to be some of extreme difficulty.) As for the second question should the bomb be made? everyone knew what the answer was going to be. This was a weapon of war, different in kind, more lethal by a thousand times than any in existence. Has any advance, even a tiny one, in a weapon of war ever been abnegated in the whole of human history? Because of the demands of human conscience, that is. Many such advances have been missed because of miscalculation or stupidity, but that is a somewhat less interesting matter.

Still, though the issue was a foregone conclusion, there were scruples, doubts, hesitations, such as there hadn't been about the first nuclear bomb. Then so it had seemed it could mean immediate life or death. This time the dangers were harder to foresee and in any case were much longer-term. Oppenheimer was in a state of moral anxiety. He lived closer to his own experience than most decision-makers, and he was in contact with what others thought about him and what he thought about himself. He would have liked a good reason, technical or military, why the hydrogen bomb shouldn't be proceeded with. He didn't find one. He was for once unable to explain his doubts with precision. Previously, though he was too sensitive for an ideal man of action, he had been able to command his own will. Now, it seems that he couldn't.

In Moscow there was a dilemma which had some family resemblances. Kapitsa decided that he could not work on the hydrogen bomb. The American and Soviet discussions and plans were proceeding almost simultaneously. Kapitsa's reasons for wanting to contract out were not the same as Oppenheimer's. Kapitsa was a civilized and enlightened man, a descendant of the professional (not landed) Russian upper cla.s.s, for so long in Tsarist times the guardians of liberal hopes. His father and paternal grandfather had both been distinguished generals in the Tsarist army, but that didn't prevent them sharing those hopes. On the other hand, a military family, however enlightened, is impelled to put the safety of the country first and foremost. Certainly Stalin thought so, and never, and rightly, had any suspicions about Kapitsa's fundamental loyalty which was fortunate for the hundred or more scientists, mainly Jewish, whom Kapitsa saved in the worst days of the purges, from 1937 to 1940, which Russians call the Yezhovshchina. Kapitsa took many risks, but, as he'd had with Rutherford, he could have some influence with Stalin. He was later known to say that those two were the only men who ever loved him.

It is unlikely that Kapitsa's main motive in refusing to collaborate on the hydrogen bomb was, in the narrow sense, humanitarian. He was a much tougher-minded man than Oppenheimer, and it is far more probable that he would have argued that if one superpower possessed this super-bomb, the other had better have it too. He always had a deep, almost sensual, Russian patriotism. It would be wrong, perhaps, to eliminate all thoughts of revulsion at ma.s.s slaughter on a world scale brought about by scientific means. A good many scientists felt that revulsion, at the time, and since. Kapitsa seems, however, to have had a more professional reason for absenting himself. His inst.i.tute, he himself, would be important figures in the H-bomb programme. The officials presumably the technical officers at the Ministry of Defence proposed to tell him what to do. That he couldn't and wouldn't take. He knew that on this kind of job he was as valuable as any man in the Soviet Union. He wanted his own way.

He remained obdurate. All that happened to him was a mild form of house-arrest. Since his house was a hundred yards across a kind of college court from his own inst.i.tute, that didn't cut him off from his own research. Scientific publications flowed in as usual. He brooded in a cla.s.sical Russian fashion. As soon as the house-arrest was called off, all acted as though it hadn't been. He received a n.o.bel prize twenty years later, in his eighties.

Large teams in the United States and the Soviet Union busied themselves with the hydrogen bomb. Some of the partic.i.p.ants in the fission bomb programme were in this project also, such as the still young John Wheeler. Not much is known of the Soviet scientists actively involved, with one exception.

In both countries two men who became, in rather different ways, world figures, had commanding responsibility for the hydrogen bomb. Both had great technical (scientific and technological) daring and exceptionally strong wills. In America Edward Teller, in the popular view, later became the chief scientific spokesman of the conservative right, and was known, rather more justly, as the father of the H-bomb. In the Soviet Union a much younger man, still in his twenties when he achieved his major work, fulfilled something close to the same function. The details are not yet known, but his achievement may have been similar to Teller's. The young man was Andrei Sakharov, whom more worldly Russians described as a pure soul rather like Dirac, and who in middle age spoke in Moscow as the most intellectually creditable of dissidents.

It doesn't need saying that the H-bomb was duly made. From start to finish, it took the American scientists just under four years and the Soviet scientists a few months longer. Once again, this was something like what cool-minded observers had reckoned on.

The H-bomb was the last dramatic contribution of high science to the world's military situation. In the 1950s it brought a sense of doom to many men of good sense and good will. It did so to Einstein, who died in 1956. He spent some of his final energies warning humanity about its dangers. He didn't do that sentimentally, for, as has been said, he was the least sentimental of men. His heart does not bleed, his eyes do not weep, said someone who idolized him. He took it as a final duty, having ceased to expect much sensible behaviour from humankind. He faced his own death with majestic and impersonal composure, saying that on this earth he had done his job. Few men could have said that with more justification.

There was one job, however, that he hadn't finished. He hadn't discovered the 'unified field theory', the search for which had occupied the second half of his life.

After his brilliant explanation of gravitation in his General Theory of Relativity back in 1915, Einstein had spent the rest of his life in an attempt to formulate a theory which would cover all the forces of nature at once. At first his unified field theory needed to combine gravitation and electromagnetism under the same set of equations. By the 1930s there was the nuclear force to include. In the 1950s, the physicists knew there were two types of nuclear force, very different in character and strength. A unified theory must cope with four forces.

For all his efforts, Einstein had no success. Having little truck with quantum mechanics, he attempted to model the other forces along the lines of General Relativity. They wouldn't go. In recent years, physicists actually have had some success in combining the theories of the two nuclear forces and electromagnetism. They have succeeded where Einstein failed because they have taken the road of quantum mechanics, not relativity. Einstein's tremendous instinct for physics had sadly gone astray, and led him up a blind alley for the last forty years of his life. When he died, he also hadn't concluded the decades-long debate with Bohr about chance and causality. He hadn't prevailed, though he was still immovable, certain that he was right. No one else was. But nothing would persuade Einstein that G.o.d played at dice.

It was a fitting departure for one of the two greatest minds that natural science has ever known. There had not been a scientist of that stature since Newton's death in 1727. Perhaps to lesser and frailer mortals it brings Einstein nearer to common earth to know that in those last years he once lost his temper. Not about the profoundest problems of physics and philosophy; not about the possibilities of ma.s.s annihilation; but about something much closer to a personal quarrel.

He was very angry, abusively angry, when Max Born, one of his oldest and most cherished colleagues, said that he intended to return to Germany for his years of retirement. Einstein couldn't understand or tolerate this. To go and live among those murderers who had slaughtered millions of 'our people'!

For the only time traceable in all Einstein's correspondence, his magnanimity, kindness, even his courtesy deserted him. He had once said that he had no ties at all, not to a nationality, a state, an inst.i.tution, even a group of friends or family. He was a solitary and all he belonged to was the human race. In old age there was an exception, but one which was discernible much earlier. It is necessary to repeat he wasn't a believing Jew. He had no G.o.d except perhaps Spinoza's impersonal G.o.d of the cosmos: but in some sense deeper than reason he had come to belong to his people, that is the Jewish people.

Born was upset by the tone of those letters, since he revered Einstein above all men. Einstein would not relent. Nothing in this life, or in the s.p.a.ce-time of the universe, would make him forget or forgive the 'final solution'.

It was in his old humane spirit that he issued his warning about world peril, and went on working at his equations the day before he died. (He had an aneurysm, had known for years that death was imminent and thought nothing of it what was mortality in this universe?) Others, not so far above the battle as Einstein, accepted more pa.s.sionately that he was right about the H-bomb. Science had made it possible for the human race to commit suicide. How wide this feeling of fatality spread, no one really knew. But it was there.

9: The Younger Masters.

MEANWHILE, particle physics to a new generation of pract.i.tioners still the central subject in physics was negating the prophecies of its decline. The war had transformed the scale of nuclear experiments. When c.o.c.kcroft built his first accelerator, in 1932, it could fit into a small laboratory. Ten years later, the tracks needed to accelerate particles could barely be fitted into an Olympic stadium. That was only the beginning. The cost of experimental research in particle physics rose beyond the financial powers of any European university. The Cavendish gave up the nuclear research which had won it fame. Only government inst.i.tutes, such as Dubna in Russia, Harwell in England, could afford the new equipment. Rutherford's apparatus had cost a few hundred pounds, c.o.c.kcroft's not much more: now the budgets ran into many millions. Experimental nuclear research, and more than half of all the experimental research in the world, of any kind whatever, could be done only in America.

In pure science, America had become by far the greatest force on earth. Great universities, including Stanford, Berkeley, MIT and Princeton, could combine with government agencies to build major nuclear apparatuses. Young scientists went to America as once they had gone to the three European plinths of physics, Cambridge, Gttingen, Copenhagen.

That change, though, was more logistic than vital. Scientists go where they can do their work, and don't repine much about the locality. It is possible that there was a slight loss in the intimate exchange of ideas, though as long as Niels Bohr lived theoreticians still spent longish spells in the cosiness of Copenhagen, and the tradition lasted when his son Aage took over. Otherwise physicists became extravagantly mobile, and their old-fashioned seniors grumbled that they were usually in the air literally rather than figuratively. No one minded. The subject had its own dynamics, and the young were indifferent to the old customs. They were taking over, and science has always been ruthless with the old.

The old, the great men of the 1920s and 1930s, were in fact pa.s.sing from the scene. Rutherford had died of a curious medical accident at sixty-six, in 1937. Einstein survived until 1956, Bohr till 1962, both dying in their late seventies. Like many of their near contemporaries, they didn't cease from trying to promote international agreements about the nuclear bomb not to much avail, except for scientific debates in organizations like Pugwash. Fermi died of cancer in his fifties, a major loss, his splendid mind unimpaired and now taking a world view. He died a modern scientist's version of a stoical Roman death, taking notes about his disease until very near the end. Oppenheimer also died relatively young at sixty-two and also of cancer. Pauli, Schrdinger, Broglie, didn't live into old age. Heinsenberg, who had become head of what once had been called the Kaiser Wilhelm Inst.i.tute, reached his seventies, as did the Cavendish stars, c.o.c.kcroft and Blackett.

Extreme longevity, though, was not an occupational feature of major scientists, as it has often been of visual artists and musicians. Of the heroic era of the 1930s the most eminent pract.i.tioners now living (1980) are Kapitsa in his middle eighties, and Dirac relatively juvenile at seventy-eight. There are, of course, plenty of men who were quite young but influential in the making of the first fission bombs, and still actively at work.

The roll-call of mortality, however, hasn't affected the march of physics. It would be astonishing if it had. Some great men seem irreplaceable. There has been only one Einstein, perhaps only one Bohr. They defy the statistical laws. But in general, the amount of scientific talent in the world must be about the same in any period, and the same applies to anything short of the most abnormal genius. As scientific education spreads to larger numbers of the world's population, as now in China, the number of available talents will increase. The only question is whether the intellectual situation (and other situations too) will give those talents the fullest possible opportunity to flourish. It may be that the circ.u.mstances of the 1920s and 1930s were abnormally propitious. Physicists today may not have the same extraordinary opportunity, and it may not have happened before in the history of science. That has been argued by observers of detachment and historical sense.

The argument is well meant; there may be a little in it, but not much. No one would think of doubting that contemporary theoreticians such as Richard Feynman, Murray Gell-Mann, Abdus Salam, Yuval Ne-eman, Freeman Dyson, would have done spectacular work if born just before 1900 and in their prime in the mid 1920s. All that is certain. It is also possible, or even probable, that they might have found it slightly easier to arrive at major conceptions, and formulations, overnight. That is open to reflection. Having said that, one has said about all that is valid on the good or bad luck of being born in 1940 rather than 1900.

The test is, what is felt inside the situation by the contemporary theorists themselves. They show the same creative satisfaction as their forerunners half a century ago. They are as confident. The great problems are showing themselves more difficult than was once thought all the better. As Rutherford in one letter encouraged Bohr, no one can expect to clear up the whole of physics in a week, and one ought to feel grateful that the enterprise looks like going on for ever.

That has been the view of the toughest-minded physicists of the century. They have enjoyed recalling that Lord Kelvin, the great nineteenth-century cla.s.sical physicist, announced around 1904 that physics had now come to an end presumably with himself. Whereas Rabi, asked recently what branch of science he would now devote himself to, if starting today as a young man (the answer expected was probably molecular biology), said with his customary robustness, 'Nuclear physics, of course.'

The present leaders would cheerfully say the same. The theoreticians might add that their recent work hasn't yet been widely a.s.similated, even among fellow professionals. There has been a longer time-lag than in the a.s.similation of quantum mechanics. That doesn't matter. Their juniors will make the exposition clearer. All scientific exposition comes to look straightforward within a generation. Richard Feynman is a major scientific figure and that is already recognized.

Feynman has performed one of the great intellectual syntheses, which lives under the general t.i.tle of quantum electrodynamics. With scientists' addiction to hilarity, it is usually called QED. It is perhaps not an accident that Einstein's paper on the Special Theory of Relativity was originally called 'On the Electrodynamics of Moving Bodies'. Feynman's is a generalization on the same scale but looking at the subject from a different point of view.

Einstein had used Maxwell's laws of electromagnetism to investigate the properties of a moving body. He found the well-known bizarre effects of relativity: a moving body becomes shortened; its ma.s.s increases; its clocks run slower. Feynman was interested in the details of electromagnetic force itself. In QED, the electric repulsion is not caused by 'action at a distance', or by a 'field' distorting s.p.a.ce and time the path that Einstein was trying to follow in his later years. Electrical and magnetic forces are the result of charged particles exchanging ent.i.ties called photons. These are in fact none other than the units of radiation, the quanta, that Planck and Einstein had discovered at the turn of the century. Here, however, they are not acting as particles of radiation. They are exchanged so quickly that scientists cannot ever detect them pa.s.sing from one body to another Heisenberg's Uncertainty Principle ensures that. But they do produce a force.

Feynman extended this concept until the theory could explain all the remaining puzzles in electricity and magnetism. QED, for example, predicts with amazing accuracy the strength of the electron's magnetic field, a quant.i.ty that simpler theories had invariably got wrong. The theory needed much heavier mathematical machinery than anything in the Special Theory of Relativity, some contributed by one of Feynman's collaborators, Freeman Dyson. Dyson is English-born, a man of formidable mathematical powers combined with a whirling imagination. Englishmen might like to say that he is a credit to English education: but he would have been a credit to any education anywhere, that kind of gift being too irrepressible to subdue.

The full importance of quantum electrodynamics has not yet been seen in perspective. The statements are accepted, but at present they look bizarre. Feynman himself looks a little bizarre by comparison with his immediate seniors. Most of them, not all, gave an external appearance of gravitas. Kapitsa, with cheek and psychological subtlety, penetrated Rutherford's facade, but no one else dared to. Bohr was not only a paterfamilias at home but a father figure to anyone around him. Nearly all the others were reasonably stately personages. Of course, some of them had their private troubles and frailties, s.e.xual, even financial, but those didn't obtrude as with a similar a.s.sembly of artists. The percentage of stable marriages among scientists has been abnormally high.

Feynman has his own style, and a very different one from Rutherford's or Bohr's. To an extent, it is a style shared by some of his contemporaries. But essentially it is Feynman's own. He would grin at himself if guilty of stately behaviour. He is a showman, and enjoys it. Since he enjoys it, he is not inclined to suppress it. He is a dashing performer. There have been a number of fine and eloquent expositors of science. W L Bragg was a splendid lecturer. Feynman is also a splendid lecturer, but in a distinctly different tone, rather as though Groucho Marx was suddenly standing in for a great scientist.

Here we ought to remember that sober-minded observers, such as the philosopher Samuel Alexander, knowing both Rutherford and Einstein when young though already world-famous, decided that Rutherford behaved like a rowdy boy and Einstein like a merry boy. The latter statement is the more interesting, in view of the moral weight that Einstein carried in later life. It may have accrued to him as life darkened him, though even in old age he could burst into bouts of jollity. It will be interesting for young men to meet Feynman in his later years.

All those capable of judging say that the theory of quantum electrodynamics is beautiful a favourite term of theoreticians' praise. In the same spirit, the present theory of sub-atomic particles strikes those inside the situation as beautiful. Outsiders, with appropriate humility, might suggest that it is a fairly rococo kind of beauty.

The memory returns to Heisenberg, in the early 1920s, going for a solitary stroll through the grounds of Bohr's inst.i.tute, and brooding over the question can nature be all that absurd? Thirty or forty years later, Heisenberg's successors could have been thinking that nature might not be all that absurd but was singularly lacking in economy. The great new particle accelerators in the United States giant descendants of c.o.c.kcroft's accelerator propelled sub-atomic particles to higher and higher energies. (Although none can travel as fast as light, the closer they get to that limiting speed, the more energy they have.) These high energy bullets were creating many new, different species of sub-atomic particles when they hit any kind of target. The comparative simplicity of a universe consisting of only three types of particles, protons, electrons, neutrons, had disappeared. These new-found particles existed only for a fraction of a second, but their existence was incontrovertible. All were heavier than the electron, most heavier even than the proton, and they came with different ma.s.ses and with different charges. Nearly all physicists believed and still believe as a matter of intuition or faith, that there must, in the very long run, be elegance and harmony in nature. A few heretics, like the immensely talented Edward Bullard, have always been convinced that this is a man-made or anthropomorphic delusion. For nearly everyone else, though, there had in the end, so they felt, to be elegance and harmony. In this new medley of particles, where had the elegance and harmony gone?

Some of the most powerful of the new generation of theoreticians weren't defeated, notably Murray Gell-Mann and his colleague Yuval Ne-eman. Yes, there was an underlying harmony and an underlying beauty, but it needed new concepts and new mathematics to read it. The new mathematics which Gell-Mann introduced was more unfamiliar than the matrix algebra which had founded quantum mechanics, and was more difficult for physicists to domesticate. If experience is any guide, that domestication will duly happen.

The new mathematical tool that Gell-Mann introduced to physics was called 'group theory'. As had happened with quantum mechanics and matrix theory, the mathematical structure had been around for a century. It had been formulated by a young French mathematician, Evariste Galois, who wrote out his ideas the night before he was due to take part in a duel. Galois was killed. But his ideas lived on, eventually to form the basis of our current understanding of the particles from which the universe is built up.

Gell-Mann noticed certain patterns amongst the newly discovered particles, when their properties were displayed on a graph. They seemed to fall into certain families, or groups. Galois' group theory applied exactly to this kind of mathematical set-up. Although other physicists were sceptical about Gell-Mann's patterns, he pointed out that the theory indicated a hole, a place in the pattern which should be occupied by a particle with certain properties. In 1964, experimenters at Brookhaven National Laboratory discovered this particle. Gell-Mann was right. The fundamental particles do form families.

Group theory was a stronger tool than this, though. It laid down rules governing the relationships in the family groups: how you would need to alter one particle to turn it into another of the same family or pattern. Gell-Mann found that this mathematical device, which evidently worked so well, corresponded to a simple physical interpretation. The 'fundamental particles' produced in the particle accelerators are composite. They are made up of smaller ent.i.ties, which Gell-Mann called 'quarks' apparently before he detected that peculiarly unsuitable word in Finnegan's Wake. Gell-Mann is deeply cultivated, an enthusiastic linguist, one of the cleverest men of the century as well as one of the deepest conceptual thinkers; but like nature itself he hasn't much taste for cla.s.sical austerity.

Quarks are very curious ent.i.ties, if ent.i.ty is the right word. They come either in twos or threes, the latter cutting across the grain of nearly all natural phenomena. Three quarks make up one proton. Quarks are not individually detectable by experimental means: they exist, but in the formal world of the new equations. They exhibit various phases of behaviour in those equations, to which theoreticians have attached terms of discrimination, such as colour, flavour, charm. These terms mean nothing except as labels in the equations themselves.

There has been nothing quite like this array of concepts in theoretical physics, or in any other branch of science before. It presents some absorbing problems in epistemology. If Einstein and Bohr were still alive, that great debate of theirs would take on another lease of existence. Theory has reached a climactic point this is the present climax, and not the final one, of a series of revolutions which began in 1900 with Planck and his quantum of radiation, climbed up to the heights of Einstein and Bohr, consolidated itself with Dirac and Heisenberg, as always in science drawing in many minds along the way, and is now expressed by Gell-Mann, Ne-eman, Salam, and a dozen others.

Those who have contributed to this intellectual edifice it is not a rhetorical flourish to say with a cool mind that it is the major intellectual achievement of our century, and will be so regarded by our successors have come from nearly all countries, different forms of society, different ethnic stocks. The names in this account tell their own story. There have been Americans, Russians, Germans, French, Italians, British, j.a.panese. A statistically disproportionate number are of Jewish origin.

There is someone who ranks with the most eminent who should be mentioned. This is Abdus Salam, who has over the past twenty-five years been a leader in the theoretical developments just discussed. Salam was born in a peasant home in a Pakistani village. He managed to get a place in the government college at Lah.o.r.e. Conceptual and mathematical ability is easy to detect at a very early age, and in Salam's case some enlightened administrator apparently did so. After Lah.o.r.e, he was despatched to Cambridge, studied with Dirac, and since then has had a creative career of continuous brilliance.

He is a citizen of the world and has devoted much of his influence and energy to help educate young scientists who come from provenances as underprivileged as his own. To this end he established the International Centre for Theoretical Physics, an inst.i.tute which has its home in Trieste, thanks to the goodwill of the Italian authorities, and Salam has vigorously commuted between the Adriatic and his home and professorship at King's College in London. The Centre has had many successes in developing the progress of scientists of all races. Few men have done more good than Salam for the talented poor.

It happens that Salam is a devout Moslem, believing pa.s.sionately in the highest axiom of Islam, the essential brotherhood of man. It is good for us to be reminded that men like Salam can translate this axiom into action.

Incidentally, Salam is probably the only committed religious believer, in the doctrinal sense, among all the great theoreticians. Many have had deep religious feelings, as Einstein had, but couldn't accept any creed or belief. Most were reverent in the face of nature, had their own personal morality, sometimes a piety towards the religion in which they had been brought up, but in which they ceased to find meaning. But Salam is, in the full sense, a religious man.

10: A Different Harvest.

THE story of particle physics continues unabated at the present day. In spite of the 1945 gloom, the 'beautiful subject' has gone on with surprises and consequences. But there have been other developments, outside the mainstream of the nuclear explorations, which deserve treatment on their own, not only for their intrinsic interest, but because they may prove to affect human lives more than any of the military applications of nuclear energy. Although most of these had roots dating back before the war, it is only in the last three decades that they have come to affect our everyday lives. All that can be done here is to make a number of perfunctory notes.

In the 193945 war a high proportion of physicists (in Britain something like 80 per cent) detached themselves from their own researches and were diverted to radar. Many of them adapted themselves with ease. If you could do one kind of physics, you could do another. They learned about the possibilities of electronics. The same trans.m.u.tation happened in America, and to an extent in Germany though, for reasons which are still not completely understood, the German use of scientists was nothing like so thorough as their use in the English-speaking world. In Britain, this concentration on electronics was good war-making. For years, it seemed the only salvation.

When the war ended, it was obvious to many good scientists that the same process could be used the other way round. If you had learned about electronics, you could take it straight into pure science. That was how the British launched into a new domain, which we now know of as radio astronomy. In wartime established scientists like Martin Ryle and Bernard Lovell, and others slightly junior J S Hey, Antony Hewish, and a good many others had studied the detection of radio waves. (They had all made important contributions to the development of radar weapons.) It was natural to turn that kind of technique and thinking to radio waves in the cosmos. A flood of discoveries followed, right up to the present day. The techniques of radio astronomy were picked up all over the world.

The meaning of some of the discoveries was argued about with considerable pa.s.sion, as was anything to do with cosmology. Those controversies will go rumbling on. But it became apparent that, just as the microscopic universe of sub-atomic particles was proving weirder than anyone had imagined, so was the macrocosmic universe of stars and galaxies.

Some of the thoughts about the microcosm brought illumination to the macrocosm, and the reverse. The annihilation of matter, the ident.i.ty of matter and energy, the existence of anti-matter, had all had a conceptual pre-figuring in the equations of Einstein, Dirac and other theoreticians of the immediate past. Now, in some interpretations of the astronomical data, one can see them happen. The only way to explain the phenomenal energy of the quasars is by matter turning into energy. And Einstein had predicted that in compact objects gravity could become so strong that nothing could escape: astronomers now have evidence that such black holes really do exist.

These findings are going to give a sense of wonder for long enough. To some of the speculations, there may not be an answer. Pessimistic scientists have been known to say that not only is the universe weirder than we can now understand, it may be weirder than we shall ever understand. That meant that there are kinds of comprehension which we can't transcend. That, however, remains very much a minority view.

In our immediate period, say 195080, physicists have also made sensational inroads into biological problems. Crystallography had always been off the mainstream of modern physics. It deals, not with the structure of nuclei and atoms, but with the geography of atoms the position of atoms in solid matter, and recently, and far more difficult, in liquid matter also. Crystallography is not only an elegant study, but one with multifarious uses. However, the nuclear scientists didn't consider it was touching the core of physics. Rutherford didn't permit it to enter the Cavendish. It might be slightly more respectable than spectroscopy, Kapitsa remarked, but both were like putting things into boxes, or perhaps a form of stamp-collecting.

Nevertheless, W L Bragg (later Sir Laurence), whom everyone agreed was a scientist of the highest cla.s.s, had devoted his scientific life to the subject. So did another man of great gifts, J D Bernal. Although chemists and geologists had been looking at the exterior forms of crystals for centuries, Bragg and Bernal could bring a twentieth-century technique to bear on the fundamental atomic structure of crystals. The key was X-rays. X-rays are radiation, like light, but with a much shorter wavelength. X-ray wavelengths at around a ten-thousand-millionth of a metre are very similar to the s.p.a.cing between atoms in a crystal. When X-rays shine on a crystal they penetrate it. But some are reflected back from the different layers and rows of atoms, and the reflected pattern gives clues to the atomic structures within the crystal. The patterns are not easy to read. It requires an experienced judgement, or complex computer programmes that have only been available in the past few years. But in principle, all the information is there, cryptically, in the pattern of reflected X-rays.

As early as the 1930s, Bragg and Bernal and their colleagues were considering ways of applying X-ray crystallographic techniques to some of the crucial problems of biology, among them the structure of the genetic material, the molecules within the living cell that determine its structure, and pa.s.s on information so that its descendants are similarly constructed. At that time, the full range of crystallographic techniques was not ready for the purpose, but the intellectual foresight was.

By the 1950s, the techniques were ripe. Experimental results on DNA (deoxyribonucleic acid) now known to be the genetic material were acc.u.mulating. The scientists who interpreted it, who showed that the DNA molecule is twisted around itself, were Francis Crick and James Watson. Watson's The Double Helix is a brilliant book and has permanent value as showing that scientists are human, or, if you like, only too human. It was generously welcomed, and by Bragg himself with supreme magnanimity. Bragg, like Einstein and Bohr, was one of the saints of science. In cool retrospect, though, the book would be more acceptable if it showed more recognition of the c.u.mulative nature of science. To repeat what has been said already, science is an edifice. To put in a brick, a scientist has to climb on the shoulders of other men, often greater men. Individuals, except for the odd anomaly who occurs once in a hundred years, don't count all that much. Both Bragg and Bernal, who knew a lot about the history of science, would have accepted that without reserve. But if one is writing a history of a specific discovery at a specific time as with DNA, it would be a distortion to leave those two out.

That said, it was a very great discovery, and will have, when the lesson has sunk in, perhaps in a generation or two, profound and to many disturbing human consequences. Human vanity will not be quite the same, nor some of the more ill-founded human hopes.

Francis Crick was a physicist by training, and had spent the war as a somewhat discontented member of one of the radar teams. Once released, he beat around for something worth doing. As it were not by second nature but by first, he had a deep sense of what was important and what might be soluble. Those two things are, of course, not the same, but a great scientist nosing his way into unexplored territory needs them both. Rutherford had that combination to the highest degree. A number of marvellously accomplished scientists haven't had it at all. As an example, there is the sad life of Einstein's closest friend and the only one he turned to for criticism, Paul Ehrenfest. Ehrenfest was a brilliant theoretician, but all his contributions were to the more abstruse branches of physics. Crick does have the necessary combination, and it was the greatest of his gifts, although for his particular gamble he needed also comprehensive intelligence and fighting spirit.

He didn't know much crystallography, and never became a supreme pract.i.tioner as Bragg and Bernal were. He learned enough for his purposes. He didn't know much biology but decided that he didn't need to know much. Unravelling the secrets of DNA was a problem where it did more harm than good to be cluttered up with preconceptions. What he did know was that once the material structure of DNA was established by X-ray crystallography, then one ought to be able to make sense out of it.

Then Watson came along, who had another of the valuable gifts, that is an eye for a winner. Each had part of the story. The rest one can learn, or infer, from Watson's book. There are some obvious points. Rosalind Franklin didn't get a fair deal the n.o.bel prize was shared between Crick, Watson and Maurice Wilkins, who had performed the vital X-ray experiments. Bernal used to say that the n.o.bel prize should have been split two ways, Crick and Franklin as one pair, Watson and Wilkins as the other. This would have had the advantage that Crick, good with women, would have been protective of Rosalind Franklin, who wasn't easy to look after.

Another point is very clear if Crick and Watson hadn't got there, and published, it wouldn't have been long, possibly only weeks, certainly not more than months, before others did. Linus Pauling in America was very nearly there, and one fresh look might have clinched it. It was a case even more striking than the Special Theory of Relativity. Several minds were converging on the same solution and understanding DNA didn't require as much conceptual apparatus as the Special Theory.

Yet there was no injustice about anything that accrued to Crick. His later work on the genetic code the way that information is actually stored in the DNA molecule was a feat of extreme intellectual skill and major significance. Here again there was a convergence. In the United States, Joshua Lederberg was reaching the same conclusions independently. Now the instructions for life are understood, genetic engineering enables man to make new kinds of living cells, to produce huge quant.i.ties of useful drugs. 'Biotechnology' is becoming a major new industry. Philosophically, the ability to alter the basis of life at will may have even more effect. The meaning of this work hasn't sunk into popular consciousness, even among intellectual persons, with anything like the rapidity of Darwin's On the Origin of Species. In the long run it may do as much or more to alter men's view of themselves.

That, though, will have to wait until the twenty-first century. What will not have to wait until the twenty-first century, but is. .h.i.tting the industrialized world here and now, is the recent domestication of electronics. For many years, it had been realized that there were great numbers of operations which men had to perform, mechanical, laborious, repet.i.tive, which ought to be given over to machines. This was true of mental operations as well as physical. Routine calculations could be done faster and more efficiently by a mechanical process than by a human mind. Bold thinkers speculated that there could be mechanical memories, more comprehensive than human ones.

There was nothing wrong with the idea. The crippling difficulty was that no one could devise a machine for any such purpose which would work anything like fast enough. Charles Babbage, a fine Victorian mathematician with an inventive flair, actually thought out and constructed a machine we now call a computer. In principle he was completely right. But his machine worked by mechanical energy and that was too slow by an order of magnitude.

Brilliant ideas have often had to wait for new techniques, but the reverse is also true: new techniques have often led to brilliant ideas. It was not until electrons, and electronic currents, began to be understood that there was any chance of a workable Babbage machine. It took a long time, technological ingenuity, concentration upon gadgets and, finally, the pressure of war. As a young man, Rutherford transmitted radio waves over a mile in Cambridge. But he immediately gave that up as a plaything, too remote from the heart of physics. It took an inventor like Marconi to persist, and make radio a commercial proposition. Improved electronic valves were an industrial development. Electronic circuits were to physicists a complicated study, but not profound the kind of topic they shied from. To see their fundamental significance needed not only inventive ingenuity, but mathematical insight.

At last that happened, and very fast, during the 193945 war. Mainly for the purposes of cryptographic decoding, a secret incomparably better kept than the nuclear bomb, computers, primitive by today's standards but just as functional, were being built. Some of the acutest minds in the Western world were at work: not world-comprehensive minds like Einstein's, but minds with a peculiarly rare specific gift. There were a number. In America there was the one-time infant prodigy, John von Neumann, born in Budapest; in England the hero was Alan Turing, whose intellect did more practical service to the country than could be credited to most household names of that war. Turing was the nearest English approach to the great von Neumann.

From that time on it was beginning to be realized that computers were going to take over a good many aspects of workaday existence. In fact, there has been too much mystification about them. They can perform many tasks which human intelligence can't: but they are of course useless without human intelligence. After all, they can always be unplugged. In memory storage, they can be given ma.s.ses of facts which no human memory can retain, reproduce them when given the necessary instructions, do with precision what they are told. And yet, even there, they can't have the fluidity and range of a decent human memory, for which, in many commonplace tasks as well as all creative ones, there is no subst.i.tute.

It is silly to be frightened by computers. Nevertheless, the social impact is bound to be c.u.mulative. That is already evident all over the industrialized world, in North America, Europe, the USSR, j.a.pan, and increasingly in parts of the Far East. Incidentally, j.a.pan is worth particular notice. The j.a.panese scientists, technologists, technocrats, have shown skills and originality in all this electronic apotheosis which quite outcla.s.s the West's. That ought to surprise no one who has given the most perfunctory attention to j.a.panese visual art or literature or pure science. For hundreds of years the culture has been wildly original, something oddly different from any other among the sons of men. It was an instance of Western blindness not to discover that simple fact.

All over the industrialized world, then, computers using the term as shorthand for all forms of automatic guidance and control are spreading. Something else is spreading. That is the realization that nearly all the goods that this industrialized world is now producing which means an enormous proportion of all the goods produced on our planet could, with such technological knowledge and a little organization, be made by not more than 40 per cent of the present labour force. Even with the present organization, industrial production, which includes modern agriculture, requires nothing like the number of workers who are now employed. If we considered nothing but functional needs, then the advanced societies of the world are already masking a high level of unemployment.

That will increase, and dramatically increase, on account of the newest, quietest, and most irreversible of technological revolutions. This is the extension of electronic control right down to the domestic scale. Computers were constructed as soon as complex electronic circuits were feasible. It has been discovered that what are in effect miniature computers can be constructed, without electronic valves at all, and without any of the labyrinthine paraphernalia. There was an element of chance in this discovery, but it came through researches into the curious properties of what are known as semi-conductors, in which electrons can travel, but not with the freedom with which they travel in metals. The element silicon is a semi-conductor. Slivers of silicon can be made into perfectly effective mini-computers which can be carried like a map in a pocket diary. And recently, and even more bizarre, it has been found that a substance previously unknown to fame, gallium a.r.s.enide, is even better fitted for the job. Silicon chips will soon be replaced by this. .h.i.therto obscure compound which has the peculiar ability to emit light like a miniature laser. There must be other comparable semi-conductors. Rapid searches are presumably being made through textbooks of inorganic chemistry.

None of this sounds specially catastrophic, by the side of nuclear explosions, or even the first blundering waves of the Industrial Revolution. Yet, as was hinted in the first section of this account, it casts a shadow before it. It is likely to affect human life and immediately in our industrialized world more than any of those events. For a simple reason. At present, as has just been mentioned, the industrialized world can produce all it now produces with a fraction of the work-force. With these mini-processors now to hand, that fraction could, and in some societies certainly will, almost at once be reduced, not just slightly, but by what? Half? Three-quarters? If production alone is the measure, more than that.

This lack of need for workers applies to productive industry, not everywhere. Service industries cannot be worked to the same extent by these subtle devices. The trouble is, as we already know all over the industrialized world, there can be destructive unemployment in productive industry, and simultaneously a corresponding demand in service industry. People insist on their old jobs in factories where they are now obsolete: at the same time they are not prepared to be postmen. If service industries paid more than factories the problem would still not disappear.

That dilemma is going to be sharpened by this most recent gift of applied physics. The curse of labour, laid on man after the Fall, is for many ready to be taken away. Like other gifts, this one may be two-edged or have two faces.

11: The Double Legacy.

THIS century, then, has not just been the triumphant age of pure physics. The successes achieved by pure physics will continue. Prediction in science, as Peter Medawar has often told us, is by definition impossible: but it will be a puzzle if those alive in fifty years' time haven't seen this process continuing and c.u.mulative. They will understand more than anyone can now imagine.

But this is also a century that has seen the profound practical results of the physicists' triumphs. There are some which lurk in the minds of reflective persons. One, which has been touched on in the last chapter, is the effect of micro-processors on industrial living everywhere. This still, in 1980, hasn't clearly entered the public consciousness. In this year, we haven't yet recognized what is going to hit us. We shall. For the moment, or for this account, we had better leave it there.

The other profound result is that reflective persons and persons not usually reflective have been living with anxiety. Here there has been a recognition, dark, looming, that something really might hit us the something being, of course, the supreme technical accomplishment, the fusion (hydrogen) bomb. The questions in many minds have been 'if' and 'when'. Is there going to be a nuclear war? When will it happen?

That dread has been hanging over us for thirty-five years, which is a long time in modern history. It wouldn't have been candid not to mention it in the first words of this book. It will continue to darken thoughts of the future for a long time yet. Some have doubted whether there is going to be a future.

And yet, it is possible to suggest that this may not be realistic. Of all the dangers in front of us, it may very well be that nuclear war is the least likely. It doesn't need saying that our world is precarious. It will remain so. But there is a subdued irony. It might have been more precarious if the hydrogen bomb had never been made. For the past thirty-five years, the two super-powers, and all others involved, have been divided by suspicion almost absolute, and by distrust even stronger than suspicion. They have exchanged insults and abuse which, by any previous precedent, would have been near declarations of war, and sometimes nearer than that. Just remember the diplomatic to-ing and fro-ing which set in motion (as if by Einstein's 'weird inevitability') the 191418 war. The language and the protests were mild compared with what we now read in each morning's paper. Austria finally sent an ultimatum to Serbia. That didn't affect real power relations any more than if America today sent an ultimatum to Cuba. At that time, it immediately led to a cataclysmic war. We have come through more articulate conflicts than that in the present in at least superficial peace. That is due to the mutual threat of nuclear bombs.

Far-sighted military commentators realized, soon after such bombs were made, that they had one curious property. Granted that both sides had enough to inflict 'unacceptable' damage, it was going to be impossible for sane governments or commanders to use them.

This is a peculiarity possessed by no other weapon of war ever made. What is 'unacceptable' damage? Here an Englishman can comment with a certain detachment. It happens that, owing to the small size of Britain, the density of population, and the extreme articulation of the whole organism, the country would be more easily destroyed in nuclear war than any other sizeable power. During one of the meetings between Harold Macmillan and President Kennedy, the British Prime Minister wished to ill.u.s.trate this point. He summoned his chief expert on nuclear weapons, William Penney. 'Sir William, would you please tell the President how many hydrogen bombs would be needed to finish our country off?' Penney answered: 'Five, I should think, Prime Minister.' Pause for reflection, and Penney continued: 'Oh, just to be on the safe side, let's say eight.'

Just to be on the safe side: those words will make a neat footnote to history. But what is true for Britain doesn't begin to apply to the United States and the Soviet Union. The United States is a very large expanse. The Soviet Union is much larger. Both sides could, in theory, inflict about the same amount of annihilation. That will remain true. There will be no help from new gadgets or technological differences. The only prospect of survival would be through the wide distribution of the population over those great areas. In this grisly arithmetic, anyone's guess is about as good as anyone else's. Things go askew in war, and it seems likely that estimates of something like total annihilation on both sides are an exaggeration. To destroy half of all Americans and half of all Soviet people would seem nearer to what nuclear exchanges could do.

Is that unacceptable, to use the egregious military terminology again? Probably: even more so, since that preliminary exchange would almost certainly be succeeded by a particularly atrocious land war with 'conventional' weapons. These calculations have to be made by military commanders and politicians. Unless the world goes even madder than the most pessimistic expect, that particular doomsday doesn't appear within the range of our potential fate.

One side comment. Nuclear war between the super-powers will continue to remain a dread, like a fear of mortal disease, but will also continue to have a low degree of probability. That, unfortunately, is not true of minor nuclear wars, as more countries come to possess the bombs. In addition to the super-powers, Britain, France, and China have demonstrated that they have them. At least two other countries certainly have them also, and very likely three or four more already. These bombs are not too difficult to make, which is a pity. In favourable circ.u.mstances, where the constraints of the super-powers did not operate, they might be used.

That is a more realistic worry than the prospect of nuclear war between the super-powers. So is the thought of such bombs getting into the hands of terrorists. These are minor anxieties by the side of the major one which has weighed on so many for so long. But these anxieties exist, and they are a negative legacy of the physicists' triumph.

Applied science, however, is two-faced. There is likely to be another, and a very great, positive legacy from that same scientific triumph. There is a chance, and a good one, that humankind will within the lifetime of today's children be certain of their supplies of energy forever. Forever is a long time: perhaps it would be better to say until the seas run dry or until the human species has had a trans.m.u.tation. Which, since there is a rough rule that species tend to change in a million years, gives a nice comfortable stretch ahead.

This chance, of the answer to the problem of energy, comes from the identical mechanism which produces the hydrogen bomb. The process is the fusion of hydrogen nuclei to make up helium nuclei. It is the way in which the sun makes its own continuous output of energy. In the hydrogen bomb, the fusion produces by terrestrial standards a very large but indiscriminate and uncontrolled outburst of energy. If this can be controlled, and domesticated for workaday uses, then the major practical problem of how to keep the human race fed and warmed and physically equipped, no longer exists. Fossil fuels oil, coal will be exhausted in an uncomfortably short time: we have wasted them with the utmost carelessness. With fusion energy as a source, the only need is hydrogen. Although hydrogen gas is not found free on our planet, the oceans are full of it, for water is made of two atoms of hydrogen to one of oxygen. There will be no side-products and nothing to disturb the apprehensive.

That is the prospect. It is the most glowing material prospect which has ever been dangled before us. It is as well to cross our fingers, touch wood, knock on wood, or do whatever our various superst.i.tions tell us to do with wood. Controlling fusion energy is the most difficult job that applied physics or physical-engineering has yet been given. The technological problems are vast, such as raising the hydrogen gas to a temperature of a hundred million degrees, the temperature needed to start the fusion reaction.

There are a good many people working on the project in America, the Soviet Union, and Britain, and the international exchange has been close. These people have been kept going by hope, faith, and reason. Which has been the most useful impulse would be hard to say. The faith is that there hasn't been a technological problem, certainly not one of supreme significance, to which an answer hasn't in due course been found. Various different attempts were started in the three countries shortly after the war. Within a few years the British believed that, in principle, they had done it. They shouted too soon. Men, usually level-headed, temporarily lost their judgement. Judicious Americans said that they were disappointed in the British: this wasn't their traditional behaviour. But perhaps there was some excuse. After all, this was the most tremendous of all scientific prizes.