William C Davidon

William C. Davidon, a professor of physics and mathematics at Haverford College, died at the age of 86 on November 8 in Highlands Ranch, CO where he had lived since 2010. Bill Davidon was born March 18, 1927 in Fort Lauderdale. He served two years in the US Navy before earning his PhD in physics from the University of Chicago in 1954. After two years at the Enrico Fermi Institute at Chicago, he moved to Argonne National Laboratory and then in 1961 to Haverford College, where he remained until his retirement in 1991. During his time at Haverford he was awarded fellowships at Aarhus University in Denmark and Trondheim University in Norway.

Bill’s published work focused on quantum electrodynamics, nonlinear optimization, and nonstandard analysis. One of his more well-known contributions was development of the original variant of the Davidon-Fletcher-Powell Algorithm, one of the earliest and most effective quasi-Newton optimization methods. When an article he wrote in 1959 while at Argonne, “Variable Metric Method of Minimization,” was first published in the SIAM Journal on Optimization in 1991, the editors remarked that it “still remains as one of the most mysterious flashes of insight in the scientific literature.”

From a young age, Bill was also a passionate advocate for peace and justice, a pacifist, and an early opponent of nuclear weapons. In September 1959, when he was head of the Chicago section of the Federation of American Scientists, a comment he made about the hydrogen bomb in a speech at the City Club of Chicago was repeated by Soviet Premier Nikita Khrushchev in his major address on disarmament before the United Nations General Assembly. He quoted Davidon’s statement that “one hydrogen bomb releases a greater amount of energy than all the explosions set off by all countries in all wars known in the entire history of mankind.”

In 1965, Bill joined the march from Selma to Montgomery Alabama led by Dr. Martin Luther King Jr. That same year, he traveled to Vietnam with five other American pacifists led by the Rev. A. J. Muste to meet with the Buddhist monk and poet Thich Nhat Hanh and other Vietnamese who opposed outside military interference by any country, whether the Soviet Union, China, or the United States. On the last day of their trip, their appointment with the American ambassador was canceled and they were expelled from the country.

In March 1971, he and two other antiwar activists met at the White House with Henry Kissinger, then President Nixon’s national security adviser, to present their arguments for removing the nuclear option from consideration for use in Vietnam and withdrawing peacefully. The dialog was cordial, but Dr. Kissinger was not convinced on either point.

During this period Bill was a national leader of the National Committee for A Sane Nuclear Policy (SANE), and of Resist, a group established to support draft resistance during the Vietnam war. He was also an active participant in the movement known as the “Catholic Left” initiated by the priests Daniel and Philip Berrigan.

In more recent years, Bill was a member of the Federation of American Scientists, Pugwash Science and World Affairs, the Union of Concerned Scientists, and the American Civil Liberties Union.

Bill is survived by his children, Sarah Davidon of Indian Hills CO, Ruth Davidon Rogers of Corte Madera CA, Alan Davidon of Phoenix AZ, and Martin Libich of Los Angeles, by his stepchildren Tracy Libros of Seattle WA, Brad Libros of Kensington MD, and Randy Libros of Melrose Park PA, and by eight grandchildren. He was preceded in death by his third wife, Maxine Libros, a Philadelphia psychotherapist, who died in 2010. Two earlier marriages ended in divorce – to the late Ann Morrissett Davidon and to Phyllis Leon. A memorial service will be held at Haverford College on Sunday December 15.