Kenneth Arrow: a gentle genius

Kenneth Arrow, one of the greatest economists of the past century, died last week. His nephew, Larry Summers, wrote a eulogy that was published in the Wall Street Journal. Here is an excerpt from it, followed by an ungated link to the full eulogy.

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. ….

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.

Larry Summers, “Farewell to Kenneth Arrow, a Gentle Genius of Economics“, Wall Street Journal, 25 February 2017 (ungated link).

HT Mark Thoma

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