Chances Are (46 page)

“Terrorism is the mirror image of insurance: its aim is to concentrate destruction, to achieve the largest and most public damage. And just as insurers diversify big risks across many smaller ones, the terrorists, once the big targets become too risky, move to more but smaller randomized attacks in a mixed strategy. It's straightforward cost/benefit analysis: what will be big enough to show the Umma, the Muslim world, that they are hurting the West, but not so big as to be too costly in resources and, especially, risk of failure? What that means for us, though, is that we can begin to formulate our own curve of severity and frequency. Just as with earthquakes, we can assess and even price terrorism risk without having the deterministic power to predict any single attack.

“These people are intelligent; their goal is to leave an imprint in history. They know that to do that means being visibly successful in hurting the West—taking lives and destroying value. Time, though, means almost nothing; if they really want to re-establish the Caliphate, they are thinking in centuries. Similarly, the lives of individual terrorists mean nothing. The only significant loss to them, in game-theory terms, is being seen to fail at something spectacular. That's why the key words for al-Qaeda are patience, preparation, and reconnaissance.”

So game theory tells us this about terrorism: despite the West's overwhelming military superiority, we are, in this dark and private battle, in the position of Lee facing Grant. We are attempting to defend all along our global perimeter against an enemy willing to spend any amount of time and blood to do us harm. We can win each battle if we choose, but to win the war means changing the matrix of the game: denying that this must be zero-sum, molding our opponent's utilities by adding new benefits. “The ambitions of the extreme Islamists are perpetual; they have no ending.” says Gordon Woo. “The only way success in the terrorist strategy loses its dominance is if success in some other form becomes possible and more attractive. The key factor is helping the aspirations of ordinary, secular Muslims—making peace worth having. This is something Western governments have hardly even tried to do.

“Since terrorism won't simply go away, governments should also be more honest about their understanding of risk and their degree of belief in intelligence information. Frankly, I think people who have gone to business school may be better qualified to evaluate these problems than people in government; at least they've been trained to reason under uncertainty. It's all probabilistic—intelligence assessment, risk analysis, decision making—and I don't think our politicians are willing to think that way or use those terms. They want to project certainty, but it simply is not there.”

 

Only in a knife fight are there no rules; war remains a matter of convention. When these conventions become confused, war's savagery increases and fighting becomes an end in itself. Herman Kahn pointed out that an important source of the horror on the Eastern Front in the Second World War was the confusion between the apparent conventions of the Wehrmacht (formal, “honorable,” aspiring to chivalry) and the anticonventional values of the SS (violent, “frightful,” power-worshiping). Even in areas where the Germans were initially welcomed, this contradiction soon turned all against the invaders: there was no understanding them.

Convention, in classical political theory, is the basis of organized society. We cooperate with one another; we pay and accept payment in pieces of paper; we stop at red lights. Game theory would ask: why? Shouldn't our individual strategy be to get all we can, shaft our neighbors and head off to a debauched retirement in Brazil? If life takes the form of a Prisoner's Dilemma, why don't we occupy the point of equilibrium, each betraying the other to Fate's policeman?

The answer seems to be that we are never playing just one game. In Kenneth Axelrod's famous experiment in 1980, individual computer programs were matched against one another in a round-robin tournament of repeated prisoner's dilemmas. Points were given on the basis of the payoffs: 3 points each for cooperation, 1 each for mutual defection, 5 for the sole defector, and zero for the trusting chump. Of 14 entrants in the first tournament and 64 in the second, the winner was one of the simplest: Anatol Rapaport's TIT FOR TAT, which cooperated on the first round and thereafter did to the opponent whatever the opponent had done on the previous round. In the electronic society, TIT FOR TAT is the solid citizen: It takes no nonsense; you can play it for a sucker only once, but if you act on the square, it sees you right. As the wise always tell us to do, it hopes for the best and prepares for the worst. Simply by adding these elements of memory and conditional behavior, Rapaport's four-line program introduces convention and thereby changes the game from Hobbes' state of nature to the beginnings of civilization.

Similar experiments in evolutionary game theory, where strategies are represented by software agents and payoffs by “reproduction,” show even more interesting dynamics: in a world where the rogue and honest citizen, greedy and fair-minded, mix and interact randomly, the rogues do well. Add, however, just a touch of preference—let the honest marginally prefer to do business with the honest, or even simply favor their nearest neighbors—and the law comes to Dodge City: the trusting structures of civil society appear, with only a small residual population of rogues picking off the unwary at the margins.

All this, though—and, with it, all the mental freedom we derive from mutual fair dealing—depends on a vital belief: that this game is not the last one; not even the next to last. We expect to live on in a world shaped by our actions of today. If we knew for certain we were playing the final hand, with no chance of future retribution, we could deal off the bottom; we could pillage, betray, and destroy. Even if we only knew for certain
which
would be the last hand, we could benefit from acting dishonestly. That is why history's most dangerous men are those who believe they know how the game ends, whether in earthly victory or in paradise.

When first it appeared, game theory seemed to provide a way of waging war that assured we could choose the least bad course. Now, the lesson of game theory seems both more subtle and more true to life: death will find us—but, we hope, not soon. In the meantime, this is the one life we are leading and our opponents, godly or godless, face choices as we do. In these circumstances, behaving decently is not just what our mothers taught us—but a pretty good strategy.

11

Being

- Max Born

 

 

 

 

 

 

 

O
utside, the night was loud with the cries of beasts; within, the lamplight shimmered on the broad table, giving his spread-out pages the air of fallen leaves shifting in a breeze. Bishop Colenso looked at the intent face of Ngidi, who had listened so closely. The day's translation was done, but the Zulu still had a question: “Is all that
true
? Do you really believe that all this happened thus? And did Noah gather food for them all, for the beasts and birds of prey, as well as the rest?” The bishop paused: he had to admit that he did not believe it
all
—setting off a chain of events that would see him vilified and excommunicated.

Are we in the same position? All those chapters ago, we were talking about a
science
of uncertainty: a form of reasoning that would stand next to logical deduction and the scientific method as a means of coming to terms with the world and plotting our course through it. In the intervening pages we have seen its surprising strengths and occasional weaknesses, following the spiral of hope and disillusionment that drives all human discovery. We tend to reset our expectations, discounting our achievements and amplifying our remaining dissatisfactions. So, yes: probability helps us make decisions, it gives us a tool to manage the recurrent but unpredictable; it helps prevent or mitigate disaster, disease, injustice, and the failure of the raisin crop—but do we really believe it? To what degree is it actually
true
—that is, something innate to the world and experience, not just to urns and wheels?

The Lloyd's A1 standard of truth for most of us would probably be classical physics. Despite having little personal experience of Newton's Laws in their purest form, we feel sure of them; we expect them to be as true Out There as they are Around Here. This confidence has two sources: first, most of us stopped studying physics when we mastered Newton, just as we stopped geometry after Euclid, and what one masters last remains most true. Second, humans happen to be a good size for Newtonian mechanics: our billiard tables and tennis courts scale up well to the planetary level.

We also cling to classical physics because Newton's universe is supremely beautiful, not just in the simplicity and power of his laws, but in the smoothness and grace of their application. The planets progress with irresistible grandeur, without even the tick of clockwork to interrupt the music of the spheres. Smooth fields of force command the motion of masses, of electricity and magnetism. The concept of limit, sketching curves beyond the resolution of any measurement, banishes that childhood terror of infinite time and space and reveals a broad continuum, where all motion has the sense of inevitability.

Except when things get small. Once our imaginations venture below the molecular scale, we find that Newton's laws no more apply throughout the universe than does the Bill of Rights. What does apply—at every scale—is probability.

One of the most puzzling experiments in physics is also one of the most pleasant: run a hot bath, climb in, and begin wiggling your toes. Wiggle only the left foot and the ripples progress smoothly up toward your nose, forming a smooth wave line along the side of the tub. Wiggle both feet and you see the pattern change: in places the waves reinforce, producing peaks twice as high as before. In others, they cancel out, creating stretches of flat calm. If you are an expert wiggler and keep your toes in sync, you can hold this interference pattern still and steady, the bands of flat and doubly disturbed water extending out toward you like rays.

In 1804 the same experiment was done with light. Cut two thin slits in a window blind and let sunlight (filtered to a single color) project onto a screen in the darkened room and you will see, not twin pools of brightness, but a pattern of alternating bands of light and dark spreading out from the center. Light, therefore, behaves like the waves in the bath, reinforcing and canceling out; no wonder we talk about wavelengths, frequencies, and amplitudes for all the various forms of electromagnetic radiation, from radio to gamma rays.

Yet we also know that light behaves like a stream of bullets, knocking off electrons from exposed surfaces: bleaching our clothes and tanning our skin. Each photon delivers a precisely defined wallop of energy, dependent on the type of radiation: dozy radio goes right through us unperceived; hustling X-rays leave a trail of damage behind. This is practical, not just theoretical, reality: we are now technically adept enough to generate these photons precisely, throttling back the fire hose delivery of a 60-watt lightbulb (10
²⁰
photons per second) to a steady drip of individual light particles.

You will already be asking what the experimenters next asked: what if we sent these particles
one by one
toward the pair of slits? For all we know, the interference pattern could have been produced by some kind of jostling among energetic photons eager to squeeze through the crush and get on. Yet even when photons are sent one by one, when there is no other photon to elbow past at the slits, the same interference pattern appears. Nor is this effect restricted to light: individual electrons, too, produce an interference pattern; even the big soccer-ball shaped molecules of carbon 60, Buckminsterfullerene, behave in a wavelike manner; it is as if they were interfering with
themselves,
splitting their identities and going through both slits at once. Even odder, if you put detectors at the slits to determine which one the particle has passed through, the effect disappears: the pattern on the screen changes to two pools of light as if no interference had taken place.

What is going on here? We are seeing at first hand the complex interaction of the Newtonian world and the quantum mechanical world. Our assumption from experience of visible, classical physics is a smooth gradation of things: temperature will move from 20 to 25 degrees through all the temperatures in between; a ball will fly from this court to that through all the positions that divide them. Quantum mechanics takes its name from the fact that the phenomena it studies do not behave this way: their fixed quantities admit no intermediate values. Electrons jump from one energy state to another; particles remain “entangled” with one another, mutually influencing observable qualities although separated by great distances. At the quantum scale, “Where is it now?” becomes both as puzzling and as pointless a question as “What does it all mean?” The observer cannot help but be part of the action. Simply looking for something (putting detectors at each slit) changes the nature of the physical system; and asking about the location of a photon without observing it is like asking, without slapping it to your wrist, whether a coin spinning in the air is showing heads or tails.

What can we describe, then, without direct observation? Probability: in quantum mechanics, probability itself is the ether through which these waves propagate. The interference pattern represents the equal probability of the photon's going through either slit; if we do not fix the photon trace by measurement, its path will follow that field of probability, effectively going through both slits at once. Position, therefore, is a concept with two forms: a wavelike field of probability until a measurement is made, a point in space thereafter.