Robert J. Aumann

Robert J. Aumann isn’t only famous for his long white beard and deep sense of wisdom. He’s also renowned for a string of controversies. On one hand, his strong political views on the Middle East conflict strike deep divisions in opinion. On the other, his work on game theory has been celebrated by the Nobel committee – recognized to have profoundly helped our understanding of conflict and how to make the world a better, more peaceful place. Aumann seeks solutions to conflicts that seem to be intractable with hard numbers and equations. The only problem is that some people may not like them.

His award-winning work and political beliefs are both driven by his own turbulent life story. Aumann is a German Jew who endured the Second World War, lived through the Cold War and now calls the heart of the Middle East conflict zone home.

The Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel, 2005

Game theorists study strategies between rational decision makers, situations of conflict and cooperation. When first meeting Aumann, hailed as the mathematical genius of game theory, he begins by discussing war, destruction and disarmament in his own emotional way. So it’s not unusual that when being asked about the everlasting conflict of mankind – war – his thoughts soon drift to butterflies.

“Nature has evolved the strategy that the male who is there, he is dominant and he owns the clearing,” says Aumann. “If two males come at the same time, then both of them leave. So nobody gets hurt. This is a correlated equilibrium. There are many things like that in nature.”

It sounds simple enough thanks to the professor. The correlated equilibrium – a theory where both parties don’t follow the same strategy but have a common knowledge of rationality – is just one of his contributions to the field and a small part of the Nobel committee’s decision to award him its highest honor.

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"War is the one constant of mankind," he explains. It’s also a very significant constant in his own life. Sitting in the living room with his second wife Batya, he’s ponders over his homemade cheesecake with the same intensity as when he philosophizes about his studies. The old German recipe reminds Aumann of his early childhood and his upbringing in Nazi-Germany. The memories are still vivid in his mind.

"In the store windows in Frankfurt, there was a sign with a light brown background and black lettering,” he says. “It was in German but was made to imitate Hebrew lettering and it said "Juden sind hier unerwünscht," which means Jews are unwanted in this store." There’s a moment of intimate silence while Aumann seems to travel through time, imitating the sound of the train that took him away from his hometown of Frankfurt. He becomes the eight-year-old boy he was in those days, his voice shaky, his eyes wet.

More or less ready to start over in the United States, "Johnny," as Aumann is known to his closest friends, experienced the pressure of the Cold War. The nuclear threat not only had a significant impact on him personally, but also on the development of game theory.

When the likelihood of nuclear war nears a tipping point, it leads to something called Mutual Assured Destruction, a situation in which neither side has any incentive to either attack or disarm. The guaranteed mutual destruction that would follow a nuclear war prevents both sides from using the weapons. A kind of nuclear stalemate.

"There are all kinds of human traits that come out of repeated games," Aumann explains. "For example, revenge. Revenge doesn’t seem to make any sense. Why take revenge? You have already suffered some kind of loss, why does it help you to take revenge on the person that inflicted this loss?"

But he argues that without revenge, there’s no deterrent. "So the revenge has to be part of the culture to enforce the cooperative behavior that takes place when people help each other, because they fear revenge. But that means that when they do harm each other, then the revenge has to be put into operation."

The crux of his theory leads to heated criticism when Aumann declares "We need to be prepared for war; we must be willing to fight in order not to fight!"

With a raised finger, Aumann points to a scribble on his office white board. It’s a quote from Barack Obama’s Nobel Prize speech that reads "The belief that peace is desirable is rarely enough to achieve it." He bangs on the table “We all like peace,” he shouts. “But how do we get it?”

Solving this question is probably the highest aim of the profession, and to do so, Aumann believes you need to dismiss the idea that war is irrational.

"If you dismiss things as being irrational, then you can’t deal with them. You haven’t helped the world. You have to give proper incentives to the sides not to go to war. If you capitulate, then you’re more likely to promote war than to avoid it. Overtly cooperative behavior which is not matched is negative, it doesn’t work."

How can we avoid war?

Aumann’s definition of rationality is different to others’. "Rationality is pursuing your own goals; this is the economics definition,” he says. “It’s to pursue your goals to the best of your ability on the basis of the information that you have. It’s not being scientific, it’s not being logical, it’s none of that."

The professor admits it’s difficult for some people to get their head around this idea and shares an example from a former student. "If a black cat crosses your path, and you spit, are you rational or irrational?” he asks. “Well, in the everyday language, you are highly irrational. It’s a stupid superstition that a black cat means bad luck, it’s an even more stupid superstition that spitting avoids bad luck. It’s highly irrational. But by the economics definition you have to spit. Because if you’re superstitious, your information is that spitting avoids bad luck."

It’s true, Aumann has been condemned for his personal political opinions about his home country. But many scientists point back to his fundamental contributions to science that have done more than anyone else of his generation to define the most rewarding questions of game theory.

For Aumann, the most challenging part, is questioning whether a theory alone can really avoid wars. His answer comes, as usual, with a rich dose of wisdom. "No theory is able to avoid wars, he proclaims emphatically. “People have to avoid wars!"