(posted by Bernhard von Stengel on 6 August 2010)

The Game Theory Society reports with sadness that its charter member David Blackwell passed away on July 8, 2010 at the age of 91.

David Blackwell was an outstanding statistician and mathematician, who contributed fundamental insights in many areas. In game theory, he provided a number of important results. One of them is a central tool known as the “Blackwell approachability theorem” (An analog of the minimax theorem for vector payoffs, Pacific J. Math. 6 (1956), 1-8.) See Eran Shmaya’s blog entry on the significance of this and other results for game theory.

The following biographical sketch is adapted from http://www.maa.org/summa/archive/blackwl.htm:

David Blackwell lived in Berkeley, California. He joined the faculty at University of California at Berkeley in 1954 after having spent ten years at Howard University, in Washington, DC, one year at Stanford, one year at Clark College, now Clark-Atlanta University, one year at Southern University, Baton Rouge, Louisiana and one year at the Institute for Advanced Study, Princeton, New Jersey.

Born in April 1919 in Centralia, Illinois, Blackwell spent ten years there attending public schools. At the age of sixteen he entered the University of Illinois in Champaign-Urbana in 1935 where he received his AB degree in 1938, his AM in 1939 and his Ph.D. in 1941; all in mathematics. At the age of 22 he had earned a Ph.D. in mathematics and had been awarded a Rosenwald Fellowship to attend the Institute for Advanced Study. This was the beginning of his more than fifty professional years as a world-class mathematician.

While at Howard University, Blackwell distinguished himself as an excellent teacher, an able leader (department chair, 1947-1954) and a very productive scholar, publishing more than twenty papers during his tenure there. When he joined the faculty at Berkeley, these characteristics became even more manifest. At Berkeley, and worldwide, he was recognized as a distinguished scholar and a gifted teacher. He chaired the Department of Statistics (1957-1961) and he published an additional 50 plus papers (a total of 80 papers prior to retirement).

His professional activities as a scholar brought him widespread recognition and acclaim. He has received honorary Doctorate of Science degrees from twelve institutions. Two of the highest honors bestowed upon him have been his election to the National Academy of Science (first and only African-American Mathematician elected) and his election to the American Academy of Arts and Sciences.

In an interview Blackwell was asked the question: “Of the areas in which you have worked, which do you think are the most significant?” He replied, “I’ve worked in so many areas; I’m sort of a dilettante. Basically, I’m not interested in doing research and I never have been … I’m interested in understanding, which is quite a different thing.” And the annals of history record that he has understood much.

From the UC Berkeley press release:

“He had this great talent for making things appear simple. He liked elegance and simplicity. That is the ultimate best thing in mathematics, if you have an insight that something seemingly complicated is really simple, but simple after the fact,” said Blackwell’s colleague Peter Bickel, a UC Berkeley professor of statistics who has known him since 1960. “Blackwell was a wonderful man and, given the trials and tribulations of his life, a very optimistic person.”

According to Bickel, Blackwell was known for his independent invention of dynamic programming, which is used today in finance and in various areas of science, including genome analysis. He also is known for the renewal theorem, used today in areas of engineering, and for independently developing the Rao-Blackwell Theorem, a fundamental concept in modern statistics.

“He went from one area to another, and he’d write a fundamental paper in each,” said Thomas Ferguson, professor emeritus of statistics at UCLA and coauthor with James MacQueen of a 1996 collection of papers in Blackwell’s honor. “He would come into a field that had been well-studied and find something really new that was remarkable; that was his forte.”

In an interview published on youtube (one of many interview snippets worth browsing) on his election to the Academy of Sciences he attributed his election to a comment by a supporter that “after Blackwell’s work, you wondered what all the fuss was about. That is, I had taken something that was complicated and showed what was really going on in a very simple way … what I did really did clarify things; I wouldn’t say it was a big thing, but it was an interesting thing.”. [The precise work in question is unfortunately not mentioned in the interview.]

David Blackwell’s curiosity and clarity of mathematical insight will remain an example for us all.