Marcos Lisboa: Kenneth Arrow e a revolução de um Nobel na economia.

Num sobrevoo por mais de 200 anos de teoria, autor explica a importância de Kenneth Arrow, que recebeu os prêmios mais relevantes de sua área, incluindo o Nobel, e morreu em fevereiro. Argumenta que ninguém contribuiu tanto quanto ele para a transformação profunda por que passou a economia em meados do século 20.

http://www1.folha.uol.com.br/ilustrissima/2017/04/1879642-kenneth-arrow-e-a-revolucao-de-um-nobel-na-economia.shtml

Lawrence H. Summers: Farewell to Kenneth Arrow, a Gentle Genius of Economics.

My mother’s brother, the Nobel economist Kenneth Arrow, died this week at the age of 95. He was a dear man and a hero to me and many others. No one else I have ever known so embodied the scholarly life well lived.

I remember like yesterday the moment when Kenneth won the Nobel Prize in 1972. Paul Samuelson—another Nobel economist and, as it happens, also my uncle—hosted a party in his honor, to which I, then a sophomore at MIT, was invited. It was a festive if slightly nerdy occasion.

As the night wore on, Paul and Kenneth were standing in a corner discussing various theorems in mathematical economics. People started leaving. Paul’s wife was looking impatient. Kenneth’s wife, my aunt Selma, put her coat on, buttoned it and started pacing at the door. Kenneth raised something known as the maximum principle and the writings of the Russian mathematician Pontryagin. Paul began a story about the great British mathematical economist and philosopher Frank Ramsey. My ride depended on this conversation ending, so I watched alertly without understanding a word.

But I did understand this: There were two people in the room who had won Nobel Prizes. They were the two people who, after everyone else was exhausted and heading home, talked on and on into the evening about the subject they loved. I learned that night about my uncles—about their passion for ideas and about the importance and excitement of what scholars do.

Kenneth’s writings resolved age-old questions and opened up vast new areas for others to explore. He likely was the most important economic theorist of the second half of the 20th century.

Is there a voting system that can be relied on to distill the will of a group of people? Many mathematicians have theorems named after them. Arrow’s impossibility theorem regarding voting and combining preferences is the only theorem I know of that is named for an economist.

Drawing upon mathematical logic, it shows that there is no possible voting scheme that can consistently and sensibly reflect the preferences of a set of individuals with diverse views. Any scheme that could ever be invented will be at risk of perverse outcomes, where, for example, the choice between options A and B is affected by the presence or absence of option C; or where a vote switch by one person toward option A makes it less likely to prevail. Mathematical and abstruse it was. But it also explained why committees have so much trouble coming to consistent conclusions and why, with an increasingly polarized electorate, democracy can become increasingly dysfunctional.

Economists have been drawn to Adam Smith’s idea of the “invisible hand” for hundreds of years. But until Kenneth drew on the techniques of topology (that is, the study of geometric properties and spatial relations), no one had ever been able to establish precise conditions under which there would be prices that would clear all markets, or under which one could assume that the market outcome was optimal. Writing in the early 1950s, he clarified the very specific conditions under which market outcomes were for the best and, of equal importance, the far more general conditions under which public interventions in markets had the potential to make things better.

For the rest of his life, Kenneth explored these conditions, writing articles on topics ranging from health insurance to public investment policy to economic growth to the limits of organizations. It is hard to imagine what economics would be like today without his contributions.

I saw him every Thanksgiving for the past 49 years with the extended family that he loved. In a family of professors, the conversation ranged widely. Save for the NFL, there was no topic—from politics to music, from classics to physics—on which Kenneth was not infinitely curious and apparently omniscient.

Kenneth knew more about everything than most know about anything, but he never flaunted his intelligence. It was another lesson for me when, many years ago, a paper was published correcting a famous analysis published by one of Kenneth’s teachers. At the time, it created a stir. I asked him what he thought. He said quietly that he had known of the error for decades, but such was his respect for his teacher that he did not publish his insight.

Rest in peace, gentle genius.

http://larrysummers.com/2017/02/25/farewell-to-kenneth-arrow-a-gentle-genius-of-economics/

Nobel Prize-winner Kenneth Arrow dies.

BY ALEX SHASHKEVICH

Nobel Prize-winning Stanford economist Kenneth Arrow died in his home in Palo Alto on Tuesday morning. He was 95.

Arrow, the Joan Kenney Professor of Economics and Professor of Operations Research, Emeritus, was a world-renowned scholar in the fields of economic theory and research operations. In addition to the Nobel Prize, he was awarded the National Medal of Science in 2004, among numerous other awards.

“Kenneth Arrow was one of the greatest economists,” said John Shoven, a professor of economics at Stanford. “But he was also humble, warm and a great friend to all of us at Stanford.”

Arrow’s pioneering contributions to general equilibrium theory and welfare theory led him to become the youngest person to date to win the Nobel Memorial Prize in Economic Sciences, which he received in 1972 together with British economist Sir John Hicks.

One of Arrow’s most influential works was his 1951 book, “Social Choice and Individual Values,” which publicized what would later be known as “Arrow’s Impossibility Theorem,” which addresses issues of collective decision-making.

But Arrow’s knowledge and accomplishments extended beyond the world of economics and statistics, according to his colleagues and family members. He was interested in a myriad of other subjects, from politics and music to mathematics and Chinese Art.

“He was as gentle as he was brilliant,” said Arrow’s nephew, Lawrence Summers, former Treasury Secretary and former president of Harvard University. “He was always an inspiration to me.”

David Arrow recalled a line from “Hamlet” when talking about his father: “He was a great human being. He was perfect in everything. I’ll never see the likes of him again.”

“I really think my father is that kind of man,” David Arrow said. “His intellectual life and influence is perhaps as profound as any in his field.”

He was also vocal about social issues. In 1988, Arrow, whose parents were Romanian-Jewish immigrants, wrote an open letter to then Israeli Prime Minister Yitzhak Shamir, challenging Shamir’s stance on an “undivided land of Israel” and pleading for an end to violence between Israelis and Palestinians. He also supported the Free South Africa Fund, which supported black South Africans’ efforts for freedom while challenging Stanford to rethink its ties with South African companies. He was a co-author of the “Economists’ Statement on Climate Change,” issued in 1997 and signed by more than 2,400 U.S. economists, detailing the hazards of global warming.

Originally from New York City, Arrow earned a bachelor’s degree from the City College of New York in 1940, and a master’s degree in mathematics from Columbia University in 1941. His academic career was interrupted by World War II, and he served as a weather officer in the U.S. Army Air Corps from 1942 to 1946.

After the war, he returned to Columbia for his PhD, and spent time as a research associate and assistant professor at the University of Chicago. He joined Stanford’s faculty as an assistant professor of economics and statistics in 1949, and remained there until 1968 when he left to teach at Harvard University for about 11 years.

But he considered Stanford home and eventually came back, his son said.

“He was proud to come back,” Arrow said. “He loved Stanford and the community here.”

Besides his accomplishments in research, Arrow valued teaching and advising students in his emeritus position until his last days, according to his son. In fact, at least five of his students also have become Nobel Prize winners.

Arrow, who became a professor emeritus in 1991, retired with his wife, Selma, at Stanford, where they lived until moving to a retirement community in Palo Alto.

“To me, to our family, he was just a very generous, loving, caring unpretentious man,” Arrow said.

Arrow is survived by his sister Anita Summers, of Philadelphia; sons David, of New York City; and Andrew, of New York City; his daughter-in-law Donna Lynn Champlin, of New York City; and his grandson, Charles Benjamin Arrow, of New York City.

http://news.stanford.edu/2017/02/21/nobel-prize-winner-kenneth-arrow-dies/