Modern Mind: An Intellectual History of the 20th Century

20

COLOSSUS

Britain declared war on Germany on a Sunday, the morning of 3 September 1939. It was a balmy day in Berlin. William Shirer, the American newspaperman who later wrote a vivid history of the rise and fall of the Third Reich, reported that the city streets were calm, but the faces of Berliners registered ‘astonishment, depression.’ Before lunch he had drinks at the Adlon Hotel with about a dozen members of the British embassy. ‘They seemed completely unmoved by events. They talked about dogs and such stuff.’

Others were required to show a greater sense of urgency. The very next day, Monday 4 September, Alan Turing reported to the Government Code and Cipher School at Bletchley Park in Buckinghamshire.¹ Bletchley town was an unlovely part of England, not far from the mud and dust of the county’s famous brickfields. It did, however, have one advantage: it was equidistant from London, Cambridge, and Oxford, the heart of intellectual Britain, and at Bletchley station the railway from London to the north crossed the local line that linked Oxford with Cambridge. North of the station, on an insignificant rise, stood Bletchley Park. In the early years of war, Bletchley’s population was swollen by two very different kinds of stranger. One kind was children, hundreds of them, evacuated from East London mainly, a precaution against the bombing that became known as the Blitz. The second kind was people like Turing, though it was never explained to the locals who these people actually were and what they were doing.² Life at Bletchley Park was so secret that the locals took against these ‘do-nothings’ and asked their local MP to table a question in Parliament. He was firmly dissuaded from doing so.³ Turing, a shy, unsophisticated man with dark hair that lay very flat on his head, found a room over a pub, the Crown, in a village about three miles away. Even though he helped in the bar when he could, the landlady made no secret of the fact that she didn’t see why an able-bodied young man like Turing shouldn’t be in the army.

In a sense, Bletchley Park had already been at war for a year when Turing arrived. In 1938 a young Polish engineer called Robert Lewinski had slipped into the British embassy in Warsaw and told the chief of military intelligence there that he had worked in Germany in a factory which made code-signalling machines. He also said he had a near-photographic memory, and could remember the details of the machine, the Enigma. The British believed him and smuggled Lewinski to Paris, where he was indeed able to help build a machine.⁴ This was the first break the British had in the secret war of codes. They knew that Enigma was used to send orders to military commanders both on land and at sea. But this was the first chance anyone had had to see it close up.

It turned out that the machine was extremely simple, but its codes were virtually unbreakable.⁵ In essence it looked like a typewriter with parts added on. The person sending the message simply typed what he or she had to say, in plain German, having first set a special key to one of a number of pointers. A series of rotor arms then scrambled the message as it was sent. At the other end, a similar machine received the message and, provided it was set to the same key, the message was automatically decoded. All personnel operating the machines were issued with a booklet indicating which key setting was to be used on which day. The rotors enabled billions of permutations. Since the key was changed three times a day, with the Germans transmitting thousands of messages in any twenty-four-hour period, the British were faced with a seemingly impossible task. The story of how the Enigma was cracked was a close secret for many years, and certainly one of the most dramatic intellectual adventures of the century. It also had highly pertinent long-term consequences – not only for the course of World War II but for the development of computers.

Turing was a key player here. Born in 1912, he had a father who worked in the Indian civil service, and the boy was sent to boarding school, where he suffered considerable psychological damage. His experience at school brought on a stutter and induced in him an eccentricity that probably contributed to his suicide some years later. He discovered in traumatic circumstances that he was homosexual, falling in love with another pupil who died from tuberculosis. Yet Turing’s brilliance at mathematics shone through, and in October 1931 he took up a scholarship at King’s College, Cambridge. This was the Cambridge of John Maynard Keynes, Arthur Eddington, James Chadwick, the Leavises, and George Hardy, another brilliant mathematician, so that intellectually at least Turing felt comfortable. His arrival in Cambridge also coincided with publication of Kurt Gödel’s famous theorem: it was an exciting time in mathematics, and with so much ferment in Germany, people like Erwin Schrödinger, Max Born, and Richard Courant, from Göttingen, all passed through.⁶ Turing duly graduated with distinction as a wrangler, was elected to a fellowship at King’s, and immediately set about trying to take maths beyond Godei. The specific problem he set himself was this: What was a computable number, and how was it calculated? To Turing, calculation was so logical, so straightforward, so independent of psychology, that it could even be followed by a machine. He therefore set about trying to describe what properties such a machine would have.

His solution had distinct echoes of Gödel’s theorem. Turing theorised first a machine that could find the number of ‘factors’ in an integer – that is, the prime numbers it is divisible by. In his account of Turing, Paul Strathern quotes a familiar example as follows:⁷

180 ÷ 2 = 90

90 ÷ 2 = 45

45 ÷ 3 = 15

15 ÷ 3 = 5

5 ÷ 5 = 1

Thus 180 = 2² × 3² × 5.

Turing believed that it would not be long before a machine was devised to follow these rules. He next assumed that a machine could be invented (as it now has) that could follow the rules of chess. Third, Turing conceived what he called a universal machine, a device that could perform all calculations. Finally (and this is where the echo of Godei is most strong), he added the following idea: assume that the universal machine responds to a list of integers corresponding to certain types of calculation. For example, 1 might mean ‘finding factors,’ 2 might mean ‘finding square roots,’ 3 might mean ‘following the rules of chess,’ and so on. What would happen, Turing now asked, if the universal machine was fed a number that corresponded to itself? How could it follow an instruction to behave as it was already doing?⁸ His point was that such a machine could not exist even in theory, and therefore, he implied, a calculation of that type was simply not computable. There were/are no rules that explain how you can prove, or disprove, something in mathematics, using mathematics itself. Turing published his paper in 1936 in the Proceedings of the London Mathematical Society, though publication was delayed because, as in Pauling’s case with the chemical bond, there was no one judged competent to referee Turing’s work. Entitled ‘On Computable Numbers,’ the paper sparked as much attention as Gödel’s ‘catastrophe’ had done.⁹ Turing’s idea was important mathematically, for it helped define what computation was. But it was also important for the fact that it envisaged a kind of machine – now called a Turing machine – that was a precursor, albeit a theoretical precursor, to the computer.

Turing spent the mid-1930s at Princeton, where he completed his Ph.D. The mathematics department there was in the same building as the recently established Institute for Advanced Study (IAS), and so he joined some of the most famous brains of the day: Einstein, Godei, Courant, Hardy, and a man he became particularly friendly with, the Austro-Hungarian mathematician Johann von Neumann. Whereas Einstein, Godei, and Turing were solitary figures, eccentric and unstylish, von Neumann was much more worldly, a sophisticate who missed the cafés and the dash of his native Vienna.¹⁰ Despite their differences, however, von Neumann was the man who most appreciated Turing’s brilliance – he invited the Englishman to join him at the IAS after he had finished his Ph.D. Though Turing was flattered, and although he liked America, finding it a more congenial environment for a homosexual, he nonetheless returned to Britain.¹¹ Here he came across another brilliant eccentric, Ludwig Wittgenstein, who had reappeared in Cambridge after many years absence. Wittgenstein’s lectures were open only to a select few, the philosopher/mathematician having lost none of his bizarre habits. Turing, like the others in the seminar, was provided with a deck chair in an otherwise bare room. The subject of the seminars was the philosophical basis of mathematics; by all accounts, Turing knew little philosophy, but he had the edge when it came to mathematics, and there were several pointed exchanges.¹²

In the middle of these battles the real war broke out, and Turing was summoned to Bletchley. There, his encounter with the military brass was almost comical: anyone less suited to army life would be hard to find. To the soldiers in uniform, Turing was positively weird. He hardly ever shaved, his trousers were held up using a tie as a belt, his stutter was as bad as ever, and he kept highly irregular hours. The only distinction that he recognised between people was intellectual ability, so he would dismiss even senior officers whom he regarded as fools and spend time instead playing chess with the lower ranks if they showed ability. Since his return from America, he was much more at home with his homosexuality, and at Bletchley often made open advances – this, at a time when homosexuality in Britain was an imprisonable offence.¹³ But cracking Enigma was an intellectual problem of a kind where he shone, so he was tolerated.¹⁴ The basic difficulty was that Turing and all the others working with him had to search through thousands of intercepted messages, looking for any regularities, and then try to understand them. Turing immediately saw that in theory at least this was a problem for a Turing machine. His response was to build an electromagnetic device capable of high-speed calculation that could accept scrambled Enigma messages and search for any regularities.¹⁵ This machine was given the name Colossus. The first Colossus (ten versions eventually became operational) was not built until December 1943.¹⁶ Details of the machine were kept secret for many years, but it is now known to have had 1,500 valves and, in later versions, 2,400 vacuum tubes computing in ‘binary’ (i.e., all information was contained in ‘bits,’ various arrangements of either 0 or 1).¹⁷ It is in this sense that Colossus is now regarded as the forerunner of the electromagnetic digital computer. Colossus was slightly taller than the size of a man, and photographs show that it occupied the entire wall of a small room in Hut F at Bletchley. It was a major advance in technology, able to scan 25,000 characters a second.¹⁸ Despite this, there was no sudden breakthrough with Enigma, and in 1943 the Atlantic convoys bringing precious food and supplies from North America were being sunk by German U-boats in worrying numbers. At the darkest time, Britain had barely enough food to last a week. However, by dogged improvements to Colossus, the time it took to crack the coded messages was reduced from several days to hours, then minutes. Finally, Bletchley’s code breakers were able to locate the whereabouts of every German U-boat in the Atlantic, and shipping losses were reduced considerably. The Germans became suspicious but never imagined that Enigma had been cracked, an expensive mistake.¹⁹

Turing’s work was regarded as so important that he was sent to America to share it with Britain’s ally.²⁰ On that visit he again met Von Neumann, who had also begun to convert the ideas from ‘On Computable Numbers’ into practice.²¹ This was to result in ENIAC (the Electronic Numerical Integrator and Calculator), built at the University of Pennsylvania. Bigger even than Colossus, this had some 19,000 valves and would in time have a direct influence on the development of computers.²² But ENIAC was not fully operational until after the war and benefited from the teething problems of Colossus.²³ There is no question that Colossus helped win the war – or at least helped Britain avoid defeat. The ‘do-nothings’ at Bletchley had proved their worth. At the end of hostilities, Turing was sent to Germany as part of a small contingent of scientists and mathematicians assigned to investigate German progress in the realm of communications.²⁴ Already, news was beginning to leak out about Colossus, not so much details about the machine itself as that Bletchley had housed ‘a great secret.’ In fact, Enigma/Colossus did not break upon the world for decades, by which time computers had become a fixture of everyday life. Turing did not live to see this; he committed suicide in 1954.

In a survey conducted well after the war was over, a group of senior British servicemen and scientists was asked what they thought were the most important scientific contributions to the outcome of the war. Those surveyed included: Lord Hankey, secretary of the Committee of Imperial Defence; Admiral Sir William Tennant, who commanded the Mulberry harbour organisation during the Normandy landings; Field Marshal Lord Slim, commander of the Fourteenth Army in Burma; Marshal of the Royal Air Force Sir John Slessor, commander-in-chief of RAF Coastal Command during the critical period of the U-boat war; Sir John Cockcroft, a nuclear physicist responsible for radar development; Professor P. M. S. Blackett, a physicist and member of the famous Tizard Committee (which oversaw the development of radar), and later one of the developers of operational research; and Professor R. V. Jones, physicist and wartime director of scientific intelligence in the Air Ministry. This group concluded that there were six important developments or devices that ‘arose or grew to stature because of the war.’ These were: atomic energy, radar, rocket propulsion, jet propulsion, automation, and operational research (there was, of course, no mention of Bletchley or Enigma). Atomic energy is considered separately in chapter 22; of the others, by far the most intellectually radical idea was radar.²⁵

Radar was an American name for a British invention. During the war, the fundamental notion came to have a great number of applications, from antisubmarine warfare to direction finding, but its most romantic role was in the Battle of Britain in 1940, when the advantage it provided to the British aircrews may just have made all the difference between victory and defeat. As early as 1928, one of the physicists at the Signals School in Portsmouth, England, took out a patent for a device that could detect ships by radio waves. Few of his superior officers believed in the need for such a piece of equipment, and the patent lapsed. Six years later, in June 1934, with the threat of German rearmament becoming clearer, the director of scientific research at the Air Ministry ordered a survey of what the ministry was doing about air defence. Collecting all fifty-three files bearing on the subject, the responsible bureaucrat saw ‘no hope in any of them.’²⁶ It was the bleak picture revealed in this survey that led directly to the establishment of the Tizard Committee, a subcommittee of the Committee of Imperial Defence. Sir Henry Tizard was an Oxford chemist, an energetic civilian, and it was his committee, formally known as the Scientific Survey of Air Defence, that pushed radar research to the point where it would make a fundamental contribution not only to Britain’s fate in World War 11, but also to aircraft safety.

Three observations came together in the development of radar. Ever since Heinrich Hertz had first shown that radio waves were related to light waves, in 1885, it had been understood that certain substances, like metal sheets, reflected these waves. In the 1920s a vast electrified layer had been discovered high in the atmosphere, which also acted as a reflector of radio waves (originally called the Heaviside Layer, after the scientist who made the discovery, it later became known as the ionosphere). Third, it was known from experiments with prototype television sets, carried out in the late 1920s, that aircraft interfered with transmission. Only in 1935 were these observations put together, but even then radar emerged almost by accident. It happened because Sir Robert Watson-Watt, in the radio department of the National Physical Laboratory in Middlesex, was researching a ‘death ray.’ He had the bloodthirsty idea that an electromagnetic beam might be created of sufficient energy to melt the thin metal skin of an aircraft and kill the crew inside. Calculations proved that this futuristic idea was a pipe dream. However, Watson-Watt’s assistant, A. F. Wilkins, the man doing the arithmetic, also realised that it might be practicable to use such a beam to detect the presence of aircraft: the beam would be re-radiated, bounced back toward the transmitting source in an ‘echo.’²⁷ Wilkins’s ideas were put to the test on 26 February 1935 near the Daventry broadcasting station in the Midlands. Tizard’s committee, closeted in a caravan, saw that the presence of an aircraft (though not, at that stage, its exact location) could indeed be detected at a distance of about eight miles. The next steps took place on the remote East Anglian coast. Masts some seventy feet high were erected, and with their aid, aircraft up to forty miles away could be tracked. By now the Tizard Committee realised that ultimate success depended on a reduction of the wave-length of the radio beams. In those days wavelengths were measured in metres, and it was not thought practicable to create wavelengths of less than 50 centimetres (20 inches). But then John Randall and Mark Oliphant at Birmingham University came up with an idea they called a cavity magnetron, essentially a glass tube with halfpennies at each end, fixed with sealing wax. The air was sucked out, creating a vacuum; an electromagnet provided a magnetic field, and a loop of wire was threaded into one of the cavities ‘in the hope that it would extract high-frequency power’ (i.e., generating shorter waves). It did.²⁸

It was now 21 February 1940.²⁹ Anticipating success, a chain of coastal radar stations, stretching from Ventnor on the Isle of Wight to the Firth of Tay in Scotland, had been begun, which meant that once the cavity magnetron had proved itself, radar stations could monitor enemy aircraft even as they were getting into formation in France and Belgium. The British were even able to gauge the rough strength of the enemy formations, their height, and their speed, and it was this ‘which enabled the famous “few,” Britain’s fighter pilots, to intercept the enemy with such success.’³⁰

*

May 1940 was for Britain and its close European allies the darkest hour of the war. On the tenth of the month German forces invaded Holland, Belgium, and Luxembourg, followed by the surrender of the Dutch and Belgian armies, with King Leopold 111 being taken prisoner. On the twenty-sixth, the evacuation of 300,000 British and French troops trapped in northeast France was begun at Dunkirk. Oswald Mosley and 750 other British fascists were interned. Neville Chamberlain resigned as prime minister, to be replaced by Winston Churchill.

Though the war dominated everyone’s thoughts, on Saturday, 25 May, two scientists in Oxford’s University Pathology Department conducted the first experiments in a series that would lead to ‘the most optimistic medical breakthrough of the century’. Ernst Chain was the son of a Russo-German industrial chemist, and an exile from Nazi Germany; N. G. Heatley was a British doctor. On that Saturday, they injected streptococci bacteria into mice and then administered some of the mice with penicillin. After that, Chain went home, but Heatley stayed in the lab until 3:30 the next morning. By then every single untreated mouse had died – but all of the treated mice were alive. When Chain returned to the pathology lab on Sunday morning, and saw what Heatley had seen, he is reported to have started dancing.³¹

The age of antibiotics had taken a while to arrive. The word antibiotic itself first entered the English language at the turn of the century. Doctors were aware that bodies have their own defences – up to a point – and since 1870 it had been known that some Penicillium moulds acted against bacteria. But until the 1920s, most medical attempts to combat microbial infection had largely failed – quinine worked for malaria, and the ‘arsenicals’ worked for syphilis, but these apart, there was a general rule that ‘chemicals’ in therapy did as much damage to the patient as to the microbe. This is why the view took hold that the best way forward was some device to take advantage of the body’s own defences, the old principle of homeopathy. A leading centre of this approach was Saint Mary’s Hospital in Paddington, in London, where one of the doctors was Alexander Fleming. To begin with, Fleming worked on the Salvarsen trials in Britain (see chapter 6). However, he dropped into the lab in Paddington one day in the summer of 1928, having been away for a couple of weeks on holiday, and having left a number of cultures in the lab to grow in dishes.³² He noticed that one culture, Penicillium, appeared to have killed the bacteria in the surrounding region.³³ Over the Following weeks, various colleagues tried the mould on themselves – on their eye infections, for example – but Fleming failed to capitalise on this early success. Who knows what Fleming would or would not have done, but for a very different man?

Howard Walter Florey (later Lord Florey, PRS; 1898–1968) was born in Australia but came to Britain in 1922 as a Rhodes scholar. He worked in Cambridge under Sir Charles Sherrington, moving on to Sheffield, then Oxford. In the 1930s his main interest was in the development of spermicidal substances that would form the basis of vaginal contraceptive gels. Besides the practical importance of the gels, their theoretical significance lay in the fact that they embodied ‘selective toxicity’ – the spermatozoa were killed without the walls of the vagina being damaged.³⁴ At Oxford, Florey recruited E. B. (later Sir Ernst) Chain (1906—1979). Chain had a Ph.D. in chemistry from the Friedrich-Wilhelm University in Berlin. Being Jewish, he had been forced to leave Germany, also relinquishing his post as the distinguished music critic of a Berlin newspaper, yet another example of the ‘inferior’ form of life that Hitler considered the Jews. Chain and Florey concentrated on three antibiotica – Bacillus subtilis, Pseudomonas pyocyanea, and Penicillium notatum. After developing a method to freeze-dry the mould (penicillin was highly unstable at ordinary temperatures), they began their all-important experiments with mice.

Encouraged by the remarkable results mentioned above, Florey and Chain arranged to repeat the experiment using human subjects. Although they obtained enough penicillin to start trials, and although the results were impressive, the experiment was nonetheless spoiled by the death of at least one patient because Florey, in wartime, could not procure enough antibiotics to continue the study.³⁵ Clearly this was unacceptable, even if the shortage was understandable in the circumstances, so Florey and Heatley left for America. Florey called in on funding agencies and pharmaceutical companies, while Heatley spent several weeks at the U.S. Department of Agriculture’s North Regional Research Laboratory in Peoria, Illinois, where they were expert at culturing microorganisms. Unfortunately, Florey didn’t get the funds he sought, and Heatley, though he found himself in the company of excellent scientists, also found them anti-British and isolationist. The result was that penicillin became an American product (the pharmaceutical companies took Florey’s results but did their own clinical trials). For many, penicillin has always been an American invention.³⁶ Without the help of the U.S. pharmaceutical companies, penicillin would no doubt not have had the impact it did (or have been so cheap so early), but the award of the Nobel Prize in 1945 to Fleming, Florey, and Chain showed that the intellectual achievement belonged to the British-Australians and the Russo-German Jew Chain.

Montignac, a small town in the Dordogne region of France, about thirty miles southeast of Périgueux, straddles the Vézère River where it has carved a narrow gorge through the limestone. On the morning of 12 September 1940, just after the Blitz had begun in London and with France already sundered into the occupied and unoccupied zones, five boys left town looking for birds and rabbits to shoot. They headed toward a wooded hill where they knew there were birch, hazel, and the small oaks that characterised the region. They saw rabbits aplenty, but no pheasant or partridge.³⁷

They moved slowly and silently so as not to disturb the wildlife. Shortly before midday they came to a shallow depression, caused some decades before when a large fir tree had been toppled in a storm. This was known to the locals as the ‘Donkey Dip’ because a donkey had once strayed into the area, broken its leg, and had to be put down. Passing the Dip, the boys moved on; the trees grew denser here, and they hoped for some birds. However, one of the boys had brought a dog, Robot, a mongrel with a dark patch over one eye. Suddenly, he was nowhere to be seen (this part of the account is now disputed – see references).³⁸ The boys were all fond of Robot and began calling for him. When he didn’t respond, they turned back, calling and whistling. Eventually, as they returned to the vicinity of the Dip, they heard the dog’s barks, but they were strangely muffled. They then realised that Robot must have fallen through a hole in the floor of the forest; there were caves all over the area, so that wasn’t too much of a surprise. Sure enough, the barking led them to a small hole, through which they dropped a stone. Listening carefully, they were surprised it took so long to fall, and then they heard it crack on other stones, then plop into water.³⁹ Breaking branches off the birch and beech trees, they hacked at the hole until the smallest of the boys could scramble down. He had taken some matches, and with their aid he soon found the dog. But that was not all he found. By the light of the matches he could see that, below ground, the narrow passage that Robot had fallen through opened out into a large hall about sixty feet long and thirty feet wide. Impressed, he called to the others to come and see. Grumbling about the birds they were missing, the others joined him. One of the things that immediately caught their eye was the rock formation in the ceiling of the cave. They were later to say that these ‘resembled nothing so much as rocky clouds, tortured into fantastic shapes by centuries of underground streams coming and going with the storms’. Alongside the rocks, however, was something even more surprising: strange paintings of animals, in red, yellow, and black. There were horses, deer, stags, and huge bulls. The deer had delicate, finely rendered antlers; the bulls were stippled, some of them, and up to their knees in grass. Still others seemed to be stampeding across the ceiling.⁴⁰

The matches soon gave out, and darkness returned. The boys walked back to the village but told no one what they had discovered. Over the following few days, leaving the village at ten-minute intervals so as not to attract attention and using a makeshift torch, they explored every nook and cranny in the cave.⁴¹ Discussing the matter among themselves, they decided to call in the local schoolteacher, M. Léon Laval. At first he suspected a practical joke. Once he saw the cave for himself, however, his attitude changed completely. In a matter of only a few days, the caves at Lascaux were visited by none other than the Abbé Breuil, an eminent archaeologist. Breuil, a French Catholic priest, was until World War 11 the most important student of cave art. He had visited even the most inaccessible sites, usually on muleback. Arrested as a spy in Portugal in World War I, he had carried on his research regardless, under armed guard, until he was cleared of all charges.⁴² At Montignac Breuil was impressed by what he saw. There was no question that the Lascaux paintings were genuine, and very old. Breuil said that the cave the boys had found was bettered only by Altamira in Spain.

When it occurred, the discovery of Lascaux was the most sensational find of its kind this century.⁴³ Prehistoric art had first been identified as such in 1879 at Altamira, a cave hidden in the folds of the Cantabrian Mountains in northern Spain. There was a personal sadness associated with this discovery, for the man who made it, Don Marcelino de Sautuola, a Spanish aristocrat and amateur archaeologist, died without ever convincing his professional colleagues that what he had found in Altamira was genuine. No one could believe that such vivid, modern-looking, fresh images were old. By the time Robot fell through that hole in Lascaux, however, too many other sites had been found for them all to be hoaxes.⁴⁴ In fact, there had been so many discoveries of cave art by the time of World War II that two things could be said with certainty. First, many of the caves with art in them were concentrated in the mountains of northern Spain and around the rivers of central France. Since then, prehistoric art has been found all over the world, but this preponderance in southern France and northern Spain still exists, and has never been satisfactorily explained. The second point relates to dating. Lascaux fitted into a sequence of prehistoric art in which simple drawings, apparently of vulvas, begin to occur around 30,000— 35,000 years ago; then came simple outline drawings, 26,000—21,000 years ago; then more painted, three-dimensional figures, after 18,000 years ago. This ‘creative explosion’ has also been paired with the development of stone tools, beginning about 31,000 years ago, and the widespread distribution of the so-called Venus figurines, big-breasted, big-buttocked carvings of females found all over Europe and Russia and dating to 28,000—26,000 years ago. Archaeologists believed at the time Lascaux was discovered that this ‘explosion’ was associated in some way with the emergence of a new species of man, the Cro-Magnon people (after the area of France where they were found), formally known as Homo sapiens sapiens, and which replaced the more archaic Homo sapiens and the Neanderthals. Related discoveries suggested that these peoples were coming together in larger numbers than ever before, a crucial development from which everything else (such as civilisation) followed.⁴⁵ Breuil’s view, shared by others, was that the Venus figurines were fertility goddesses and the cave paintings primitive forms of ‘sympathetic magic.’⁴⁶ In other words, early man believed he could improve his kill rate in the hunt by ‘capturing’ the animals he wanted on the walls of what would be a sacred place, and making offerings to them. After the war, at another French site known as Trois Frères, a painting of a figure was discovered that appears to show a human wearing a bison skin and a mask with antlers. Was this ‘sorcerer’ (as he became known), a primitive form of shaman? If so, it would support the idea of sympathetic magic. One final mystery remains: this explosion of creative activity appears to have died out about 10,000 years ago. Again, no one knows why.

Halfway across the world, much rarer evidence relating to man’s remote past became a direct casualty of hostilities. China and Japan had been at war since 1937. The Japanese had invaded Java at the end of February 1941 and were advancing through Burma. In June, they attacked the U.S. Aleutian chain – China was being encircled. Among these great affairs of state, a few old bones counted for not very much. But in fact the hominid fossils from the cave of Zhoukoudien were just about as important as any anthropological/archaeological relic could be.

Until World War II, such evidence as existed for early man had been found mainly in Europe and Asia. The most famous were the bones and skulls unearthed in 1856 in a small cave in the steep side of the Neander Valley (Neander Thal), through which the river Düssel reaches the Rhine. Found in sediments dating to 200,000 to 400,000 years old, these remains raised the possibility that Neanderthal man was our ancestor. More modern-looking skulls had been found at Cro-Magnon (‘Big Cliff) in the valley of the Vézère River in France, suggesting that modern man had lived side by side with Neanderthals.⁴⁷ And the anatomical details of Raymond Dart’s discovery, in South Africa in 1925, of Australipithecus africanus, ‘the man-ape of South Africa,’ implied that the find spot, a place called Taung, near Johannesburg, was where the apes had first left the trees and walked upright. But more discoveries had been made in Asia, in China and Java, associated with fire and crude stone artefacts. It was believed at that stage that most of the characteristics that made the early hominids human first appeared in Asia, which made the bones found at Zhoukoudien so significant.

Chinese academics raised the possibility of sending these precious objects to the United States for safety. Throughout most of 1941, however, the custodians of the bones dithered, and the decision to export them was not made until shortly before the attack on Pearl Harbor in December that year.⁴⁸ Barely twenty-four hours after the attack, the Japanese in Beijing searched the fossils’ repository. They found only casts. That did not mean, however, that the fossils were safe. What appears to have happened is that they were packed in a couple of footlockers and put in the care of a platoon of U.S. Marines headed for the port of Tientsin. The plan was for the fossils to be loaded on board the SS President Harrison, bound for home. Unfortunately, the Harrison was sunk on her way to the port, and the fossils vanished. They have never been found.

The Zhoukoudien fossils were vital because they helped clarify the theory of evolution, which at the outbreak of war was in a state of chaos. Throughout the 1930s, the attention of palaeontologists had continued to focus on Zhoukoudien, in China, rather than Java or Africa for the simple reason that spectacular discoveries continued to be made there. In 1939, for example, Franz Weidenreich reported that of the forty or so individuals found in the Zhoukoudien caves (fifteen of whom were children), not one was a complete skeleton. In fact, the great preponderance were skulls, and smashed skulls at that. Weidenreich’s conclusion was dramatic: these individuals had been killed – and eaten. The remains were an early ritualistic killing, a primitive religion in which the murderers had eaten the brains of their victims in order to obtain their power. Striking as these observations were, evolutionary theory and its relation to known fossils was still incoherent and unsatisfactory.⁴⁹

The incoherence was removed by four theoretical books, all published between 1937 and 1944, and thanks to these four authors several nineteenth-century notions were finally laid to rest. Between them, these studies created what is now known as ‘the evolutionary synthesis,’ which produced our modern understanding of how evolution actually works. In chronological order, these books were: Genetics and the Origin of Species, by Theodosius Dobzhansky (1937); Evolution: The Modern Synthesis, by Julian Huxley (1942); Systematics and the Origin of Species, by Ernst Mayr (also 1942); and Tempo and Mode in Evolution, by George Gaylord Simpson (1944). The essential problem they all sought to deal with was this:⁵⁰ Following the publication of Charles Darwin’s On the Origin of Species in 1859, two of his theories were accepted relatively quickly, but two others were not. The idea of evolution itself – that species change – was readily grasped, as was the idea of ‘branching evolution,’ that all species are descended from a common ancestor. What was not accepted so easily was the idea of gradual change, or of natural selection as an engine of change. In addition, Darwin, in spite of the tide of his book, had failed to provide an account of speciation, how new species arise. This made for three major areas of disagreement.

The main arguments may be described as follows. First, many biologists believed in ‘saltation’ – that evolution proceeded not gradually but in large jumps; only in this way, they thought, could the great differences between species be accounted for.⁵¹ If evolution proceeded gradually, why wasn’t this reflected in the fossil record; why weren’t ‘halfway’ species ever found? Second, there was the notion of ‘orthogenesis,’ that the direction of evolution was somehow preordained, that organisms somehow had a final destiny toward which they were evolving. And third, there was a widespread belief in ‘soft’ inheritance, better known as the inheritance of acquired characteristics, or Lamarckism. Julian Huxley, grandson of T. H. Huxley, ‘Darwin’s bulldog,’ and the brother of Aldous, author of Brave New World, was the first to use the word synthesis, but he was really the least original of the four. What the others did between them was to bring together the latest developments in genetics, cytology, embryology, palaeontology, systematics, and population studies to show how the new discoveries fitted together under the umbrella of Darwinism.

Ernst Mayr, a German emigré who had been at the Museum of Natural History in New York since 1931, directed attention away from individuals and toward populations. He argued that the traditional view, that species consist of large numbers of individuals and that each conforms to a basic archetype, was wrong. Instead, species consist of populations, clusters of unique individuals where there is no ideal type.⁵² For example, the human races around the world are different, but also alike in certain respects; above all, they can interbreed. Mayr advanced the view that, in mammals at least, major geographical boundaries – like mountains or seas – are needed for speciation to occur, for then different populations become separated and begin developing along separate lines. Again as an example, this could be happening with different races, and may have been happening for several thousand years – but it is a gradual process, and the races are still nowhere near being ‘isolated genetic packages,’ which is the definition of a species. Dobzhansky, a Russian who had escaped to New York just before Stalin’s Great Break in 1928 to work with T. H. Morgan, covered broadly the same area but looked more closely at genetics and palaeontology. He was able to show that the spread of different fossilised species around the world was directly related to ancient geological and geographical events. Dobzhansky also argued that the similarity of Peking Man and Java Man implied a greater simplicity in man’s descent, suggesting there had been fewer, rather than a greater number of, ancestors. He believed it was highly unlikely that more than one hominid form occupied the earth at a time, as compared with the prewar view that there may have been several.⁵³ Simpson, Mayr’s colleague at the American Museum of Natural History, looked at the pace of evolutionary change and the rates of mutation. He was able to confirm that the known rates of mutation in genes produced sufficient variation sufficiently often to account for the diversity we see on earth. Classical Darwinism was thus reinforced, and all the lingering theories of saltation, Lamarckianism, and orthogenesis were killed off. Such theories were finally laid to rest (in the West anyway) at a symposium at Princeton in 1947. After this, biologists with an interest in evolution usually referred to themselves as ‘neo-Darwinists.’

What Is Life? published in 1944 by Erwin Schrödinger, was not part of the evolutionary synthesis, but it played an equally important part in pushing biology forward. Schrödinger, born in Vienna in 1887, had worked as a physicist at the university there after graduating, then in Zurich, Jena, and Breslau before succeeding Max Planck as professor of theoretical physics in Berlin. He had been awarded the 1933 Nobel Prize for his part (along with Werner Heisenberg and Paul Dirac) in the quantum mechanics revolution considered in chapter 15, ‘The Golden Age of Physics.’ In the same year that he had won the Nobel, Schrödinger had left Germany in disgust at the Nazi regime. He had been elected a fellow of Magdalen College, Oxford, and taught in Belgium, but in October 1939 he moved on to Dublin, since in Britain he would have been forced to contend with his ‘enemy alien’ status.

An added attraction of Dublin was its brand-new Institute for Advanced Studies, modelled on the IAS at Princeton and the brainchild of Eamon de Valera (‘Dev’), the Irish taoiseach, or prime minister. Schrödinger agreed to give the statutory public lectures for 1943 and took as his theme an attempted marriage between physics and biology, especially as it related to the most fundamental aspects of life itself and heredity. The lectures were described as ‘semi-popular,’ but in fact they were by no means easy for a general audience, containing a certain amount of mathematics and physics. Despite this, the lectures were so well attended that all three, originally given on Fridays in February, had to be repeated on Mondays.⁵⁴ Even Time magazine reported the excitement in Dublin.

In the lectures, Schrödinger attempted two things. He considered how a physicist might define life. The answer he gave was that a life system was one that took order from order, ‘drinking orderliness from a suitable environment.’⁵⁵ Such a procedure, he said, could not be accommodated by the second law of thermodynamics, with its implications for entropy, and so he forecast that although life processes would eventually be explicable by physics, they would be new laws of physics, unknown at that time. Perhaps more interesting, and certainly more influential, was his other argument. This was to look at the hereditary structure, the chromosome, from the point of view of the physicist. It was in this regard that Schrödinger’s lectures (and later his book) could be said to be semipopular. In 1943 most biologists were unaware of both quantum physics and the latest development on the chemical bond. (Schrödinger had been in Zurich when Fritz London and Walter Heider discovered the bond; no reference is made in What Is Life? to Linus Pauling.) Schrödinger showed that, from the physics already known, the gene must be ‘an aperiodic crystal,’ that is, ‘a regular array of repeating units in which the individual units are not all the same.’⁵⁶ In other words, it was a structure half-familiar already to science. He explained that the behaviour of individual atoms could be known only statistically; therefore, for genes to act with the very great precision and stability that they did, they must be a minimum size, with a minimum number of atoms. Again using the latest physics, he also showed that the dimensions of individual genes along the chromosome could therefore be calculated (the figure he gave was 300 A, or Angstrom units), and from that both the number of atoms in each gene and the amount of energy needed to create mutations could be worked out. The rate of mutation, he said, corresponded well with these calculations, as did the discrete character of mutations themselves, which recalled the nature of quantum physics, where intermediate energy levels do not exist.

All this was new for most biologists in 1943, but Schrödinger went further, to infer that the gene must consist of a long, highly stable molecule that contains a code. He compared this code to the Morse code, in the sense that even a small number of basic units would provide great diversity.⁵⁷ Schrödinger was thus the first person to use the term code, and it was this, and the fact that physics had something to say about biology, that attracted the attention of biologists and made his lectures and subsequent book so influential.⁵⁸ On the basis of his reasoning, Schrödinger concluded that the gene must be ‘a large protein molecule, in which every atom, every radical, every heterocyclic ring, plays an individual role.’⁵⁹ The chromosome, he said, is a message written in code. Ironically, just as Schrödinger’s basic contribution was the application of the new physics to biology, so he himself was unaware that, at the very time his lectures were delivered, Oswald Thomas Avery, across the Atlantic at the Rockefeller Institute for Medical Research in New York, was discovering that ‘the transforming principle’ at the heart of the gene was not a protein but deoxyribonucleic acid, or DNA.⁶⁰

When he came to convert his lectures into a book, Schrödinger added an epilogue. Even as a young man, he had been interested in Vedanta, the Hindu doctrine, and in the epdogue he considered the question – central to Hindu thought – that the personal self is identical with the ‘all-comprehending universal self.’ He admitted that this was both ‘ludicrous and blasphemous’ in Christian thought but still believed the idea was worth advancing. This was enough to cause the Catholic Dublin publishing house that was considering releasing the lectures in print to turn its back on Schrödinger, even though the text had already been set in type. The title was released instead by Cambridge University Press a year later, in 1944.

Despite the epilogue, the book proved very influential; it is probably the most important work of biology written by a physicist. Timing also had something to do with the book’s influence: not a few physicists were turned off their own subject by the development of the atomic bomb. At any rate, among those who read What Is Life? and were excited by its arguments were Francis Crick, James Watson, and Maurice Wilkins. What they did with Schrödinger’s ideas is considered in a later chapter.

Intellectually speaking, the most significant consequence of World War II was that science came of age. The power of physics, chemistry, and the other disciplines had been appreciated before, of course. But radar, Colossus, and the atomic bomb, not to mention a host of lesser discoveries – like operational research, new methods of psychological assessment, magnetic tape, and the first helicopters – directly affected the outcome of the war, much more so than the scientific innovations (such as the IQ test) in World War I. Science was itself now a – or perhaps the — colossus in affairs. Partly as a result of that, whereas the earlier war had been followed by an era of pessimism, World War II, despite the enormous shallow of the atomic bomb, was followed by the opposite mood, an optimistic belief that science could be harnessed for the benefit of ad. In time this gave rise to the idea of The Great Society.