During the 1960s and ’70s, Dr. Anderson explored the theory of superconductivity, in which certain alloys and metals lose all resistance to electrical currents at temperatures near absolute zero. Later in his career, he turned to high-temperature superconductors, which operate at higher temperatures — though still frigid — than traditional superconductors, resulting in more efficient electrical transmission.
Just as important as Dr. Anderson’s technical achievements were his tireless — at times, feisty — advocacy for condensed-matter physics, which have come to dominate the profession, and the role of complexity in science.
“He was a brilliant intuitionist” who “gave depth and intellectual coherence to an entire field,” said Andrew Zangwill, a physics professor at Georgia Tech, who is writing a biography of Dr. Anderson.
In 1972, Dr. Anderson stirred up the physics world with an article in the journal Science called “More Is Different,” which became part of a spirited debate about the widely accepted concept of reductionism in science. Reductionism maintains that everything can be reduced to a few fundamental laws describing the particles that are the basic constituents of matter.
Dr. Anderson focused instead on the limitations of reductionism, arguing that in certain materials entirely different properties emerge when enough individual particles — whether atoms or molecules — are collected together. A single copper atom, for example, has little electrical charge, but millions of copper atoms gathered in a wire can conduct electricity.
His colleague Murray Gell-Mann, who died last May, liked to disparage Dr. Anderson’s field as “squalid state physics,” reflecting the notion that particle physics, Dr. Gell-Mann’s specialty, was a purer and superior endeavor.
Phillip Warren Anderson was born on Dec. 13, 1923, in Indianapolis to Harry Warren Anderson and Elsie Elinore (Osborne) Anderson and grew up on a farm in Urbana, Ill. His father was a professor of plant pathology at the University of Illinois, Urbana-Champaign; and his mother, a homemaker, was the daughter and sister of professors at Wabash College in Indiana. “On both sides my family were secure but impecunious Midwestern academics,” Dr. Anderson wrote in his Nobel biography.