Dreamers and Deceivers (24 page)

As he cycled from Cologne to Göttingen, which just so happened to be the math capital of the world, the five-foot, ten-inch mathematician with the bright blue eyes, unkempt hair, and omnipresent five o’clock shadow thought back to a puzzle that had attracted his attention in his last year of college. It was called “the decision problem” and the basic question it posited was whether a single mechanical method exists that could always correctly decide whether a mathematical assertion was provable. In other words, was it possible to design a set of principles that, if applied correctly, could serve as a lie detector for mathematical theories?

Three decades earlier, David Hilbert, the godfather of Alan’s generation of mathematicians, had hypothesized that the answer was “yes.” Alan Turing disagreed.

Alan had fallen in love with the predictability and reliability of numbers, but he never presumed that their dependability precluded the value of new ideas. He didn’t think that any single mechanical method could account for the infinite possibilities of numbers. And because man can manipulate numbers creatively, man needs creativity to prove the assertions he makes with those numbers. There is—
there must be
—Alan thought, a perpetual need for more intuition and innovation than any one single mechanical method could ever provide.

Far from using the trip as an escape from math, Alan spent the hours on his bicycle pondering the decision problem. He found himself enjoying the journey from town to town and feeling disappointed when he arrived at hostels and pubs at the end of the day. While he was bighearted and quick to share a laugh with those he knew well, he was uncomfortable around strangers. He despised small talk because he never knew what to say. That generally led him to say whatever was on his mind, which, unintentionally, often bored, insulted, or baffled his listeners.

Alan disdained pomposity and hierarchy of any sort. He never suffered fools or foolishness gladly. That attitude didn’t fit well in Nazi Germany, where it was dangerous to speak one’s mind. Alan didn’t go around purposely insulting the Führer, whom he viewed as more idiotic than evil, but he was unwilling to acknowledge “Heil Hitler” salutes. Nazism, with its inane slogans and silly salutes, seemed especially foolish to him.

English-speaking foreigners who refused to play by the Nazis’ rules were occasionally beaten up or harassed, but Alan skated by without any real trouble. For all of his short life, he’d been playing by his own set of rules, and so far, his luck had held out.

It never occurred to the absentminded soon-to-be professor that his good fortune wouldn’t last forever.

Cambridge, England

March 15, 1935

The twenty-two-year-old Cambridge don had added marathon training to his other hobbies, which included tennis, competing in bridge tournaments, and going to the cinema. Of course, he still pursued his interest in codes and amateur cryptography. But of all these pastimes, running was his favorite. It afforded him an opportunity to be alone, to release pent-up energy, and to daydream among the natural wonders of England’s rolling hills and glistening rivers.

As usual, today’s early-morning run began along the beautifully manicured quad of King’s College, then through the school’s ancient gates, down its cobblestone streets, past the towering spires of England’s seven-hundred-year-old university, and across the River Cam and Bourn Brook. Alan started relatively slow but increased his speed with every mile. By the time he had hit the ten-mile mark he felt like he was flying.

His wide, looping route eventually brought him back to within earshot of the university’s bell towers. He stopped in a quiet meadow just outside the Cambridge city limits in a little village called Grantchester. The dew was still on the grass, and Alan lay flat on his back staring at the sky.

Imagine a machine that could read instructions,
he said out loud to himself.

I think a machine like that,
he continued, a bit unsure of how far he could take this line of thought,
could be the answer to the decision problem. It could disprove Hilbert’s hypothesis.

Alan paused. His speech had a natural hesitation to it, as if the words on his lips were having a hard time keeping pace with the thoughts in his head. At times like this, he wanted his speech to match the precision of his mind.

He continued thinking out loud.
The machine would scan a tape, and the tape would have a numeric code on it. The code tells the machine what to do, and the machine does it.

With that, the pace of his thoughts picked up, and the tone of his voice reflected a budding confidence.
At any given moment,
he
continued, sitting up now and barely unable to contain his excitement,
the machine is reading one space on a tape, which moves backward and forward across the machine’s eye, and based on what the tape tells it, the machine will write more things on the tape. Imagine it! Numbers that talk to a machine, and a machine that talks back—with new and different numbers!

The part of the tape that the machine isn’t currently reading would be like our memory,
he continued.
It would be the machine’s memory. And anyone who writes code for the tape could add to the machine’s memory. Anyone who writes a proper code can instruct the machine to do almost anything.

His arms were waving, and he was growing increasingly animated. He began to think of the possibilities.
With the right code, the machine could play music! Or chess! It could add numbers! It could process words! It would be like a phonograph and an adding machine and a typewriter—all in one single machine! It could hold the answers to countless questions, and the only thing you’d have to do to find out the answer is ask the question in a language the machine can understand!

By now, he was bubbling over with excitement, pacing around the meadow as a cool breeze blew his sweat-streaked hair from side to side. He remembered a line from Brewster’s
Natural Wonders Every Child Should Know:
“The body is a machine.” If that were true, then why couldn’t the inverse be true? Why couldn’t a machine be a body—or at least have a mind of its own?

•  •  •

Alan Turing quickly realized that his concept of this machine would allow him to prove he was correct about the “decision problem,” because he could use it to illustrate that, in mathematics, there is always room for more intuition and innovation than any one single mechanical method, or machine, can provide. But there was much that he did not yet realize. He didn’t yet know, for example, that he’d just given birth to the concept for history’s most powerful and transformative machine. He didn’t yet know that the codes he imagined would be the backbone of what we now call software. Nor did he know that the machine he imagined would one day be called a computer. Instead, alone in an English meadow, Alan Turing became the first person to not just dream of a machine with the capabilities of the computers we now
know, but to actually put together in his mind the technical elements of how that machine could be built.

Cambridge, England

October 28, 1938

Alan had seen countless comedies, mysteries, westerns, and dramas at Cambridge’s Regent Street Picture House, but he had never seen anything quite like this: a full-length animated feature film called
Snow White and the Seven Dwarfs
.

Alan’s head bobbed along to the song “Whistle While You Work,” and he laughed at Snow White’s little friends, who were almost as eccentric as he was. But his favorite scene by far was one of the creepy moments of the film that juxtaposed cruelty with kindness, monstrous ugliness with angelic beauty, and death with life.

Alan sat with rapt attention as the cackling queen on the big screen dipped an apple in poison. As the chemicals covered the skin of the fruit with a skull and crossbones, the evil queen—disguised as an elderly hag—commanded her pet raven: “Look at the skin: a symbol of what lies within.” Then she ordered the apple to “turn red to tempt Snow White, to make her hunger for a bite.”

In between bouts of maniacal laughter, the queen explained to the raven, “When she breaks the tender peel, to taste the apple from my hand, her breath will still, her blood congeal. And then
I’ll
be the fairest in the land!”

For whatever reason, Alan loved Walt Disney’s
Snow White and the Seven Dwarfs
. Perhaps it was his lifelong interest in poisons. Maybe it was simply the eccentric, Peter Pan element of his personality, which had never warmed to the protocols and rigid expectations of English adults. Or, perhaps, it was a soft spot for the poison’s romantic antidote: “The victim of the sleeping death,” chanted the wicked queen, “can be revived only by Love’s First Kiss.” In the case of Snow White, that meant Prince Charming.

After seeing the movie, Alan made a habit of eating an apple every
night before bed. Throughout the fall of 1938, while Britain’s prime minister Neville Chamberlain appeased Hitler, and Molotov began the Soviet Union’s negotiations with the German Reich’s von Ribbentrop that would eventually culminate in the Nazi-Soviet Non-Aggression Pact, the young Cambridge don who had solved the decision problem and invented the idea of the computer could often be heard quietly singing to himself his favorite couplet from the evil queen’s incantation: “Dip the apple in the brew. Let the sleeping death seep through.”

Cambridge, England

September 3, 1939

The prime minister’s voice came crackling over the radio at 11:15 that morning. Alan listened alone from his untidy Cambridge apartment.

“This morning,” Neville Chamberlain declared, “the British ambassador in Berlin handed the German government a final note stating that, unless we heard from them by eleven o’clock, that they were prepared at once to withdraw their troops from Poland, a state of war would exist between us.”

And then came the announcement Chamberlain had worked so hard at Munich to avoid making: “I have to tell you now that no such undertaking has been received, and that consequently this country is at war with Germany.”

It would mean a blockade of their island. It could mean an aerial bombardment of London. It might even mean the first successful invasion of Great Britain since William the Conqueror had landed in 1066, not far from the seaside town where Alan Turing grew up.

“You can imagine what a bitter blow it is to me,” said Chamberlain, “that all my long struggle to win peace has failed.” But Hitler’s invasion of Poland—unlike, by Chamberlain’s shortsighted reckoning, Hitler’s remilitarization of the Rhineland, annexation of Austria, and conquest of Czechoslovakia—“shows convincingly that there is no chance of expecting that this man will ever give up his practice of using force to gain his will. He can only be stopped by force. . . . I know that you will all play your part with calmness and courage.”

Calmness and courage had never been in short supply among Englishmen—or in Alan Turing. He had complete confidence in himself and his country, along with complete contempt for the German Führer, whose capacity for evil he had clearly underestimated. Even before Chamberlain’s three-minute speech was over, Alan knew exactly how he could best play his part to help save England and defeat Hitler.

“You may be taking your part in the fighting services or as a volunteer in one of the branches of civil defense,” said Chamberlain. “If so you will report for duty in accordance with the instructions you have received.”

Alan didn’t expect his service to include an assignment to a branch of the armed forces or the civil defense, but he knew he would serve His Majesty’s Government somehow.

“Now may God bless you all,” concluded Chamberlain. “May He defend the right. It is the evil things that we shall be fighting against—brute force, bad faith, injustice, oppression, and persecution—and against them I am certain that the right will prevail.”

The next day, Alan Turing reported for duty, which, like so much in his life, would not be conventional at all.

Bletchley Park

September 4, 1939

Alan left the living quarters he was assigned at the Crown Inn at Shenley Brook End and rode his bike to his new place of business: a large, garish manor house that had been redecorated too often by too many owners with more money than taste. Both the exterior and interior of the house incorporated design elements from five different periods: Romanesque, Gothic, Tudor, Neo-Norman, and Victorian. The result was an expensively redesigned eyesore. Alan’s first impression of the house was that it was proof of Leonardo da Vinci’s axiom: “Simplicity is the ultimate sophistication.”

The manor house stood on a hill overlooking the grounds of Bletchley Park, the new home of the Government Code and Cipher School. The school—which would never have any real students and which was
less a “school” than a laboratory for code-breaking—had recently been moved out of London in order to protect its secrecy, and because its most important staff would be drawn from the faculties of Oxford and Cambridge.

Bletchley Park was a natural choice for a location because it sat on a rail line halfway between the two universities. Its isolation in the English countryside would minimize the number of nosy neighbors, and its sprawling grounds and somewhat elegant ambiance might reduce the natural stress of those who chose to accept its mission: breaking the secret code used by every Nazi field commander, air traffic controller, and U-boat captain trying to blockade Britain and starve its citizens into submission.

Alan arrived at the manor house, parked his bicycle, and proceeded to an elegant meeting room. He took his seat at a small antique table surrounded by seven men with a professorial air about them. Standing at the head of the table with a slide projector screen behind him was Bletchley Park’s director, Commander Alastair Denniston.

“The Nazi code-making machine is called the Enigma,” Denniston began. “The purpose of this orientation session is to tell you how the Enigma works.

“Secret codes have been used by militaries for millennia. Julius Caesar used to write orders in which each written letter would represent the letter that was three letters before it. So, if he wrote ‘Jdxo,’ it meant ‘Gaul.’ Pretty simple, right?”