John Holland, internationally eminent Professor of Psychology and of Electrical Engineering and Computer Science at the University of Michigan, passed away on August 9, 2015 in Ann Arbor, Michigan.   Professor Holland was one of the founders of the innovative interdisciplinary field of Complex Systems.  He received the first Ph.D. in Computer Science ever awarded by the University of Michigan, conferred in 1959, as doctoral student of Arthur Burks, co-designer of some of the original all-purpose electronic digital computers.

Numerous prestigious awards and honors were bestowed upon Professor Holland over the years. In 1961, he received the Louis Levy Medal from The Franklin Institute. He was awarded a MacArthur Fellowship in 1992, and earned the University of Michigan’s highest distinction for a senior faculty member, the Henry Russel Lectureship, in 1993. Holland was also a fellow of the World Economic Forum, and served as a member of the Board of Trustees and the Science Board at the Santa Fe Institute, a world-renowned research ‘think tank’ devoted to the study of complex systems.

Professor Holland’s seminal 1975 book, Adaptation in Complex Adaptive Systems, applied fundamental ideas from biology to help define the nascent field of adaptive computation.  In it he introduced the world to genetic algorithms and learning classifier systems: two powerful now-standard tools of adaptive computation that his research had constructed out of whole cloth. This book was well ahead of its time.  Over forty years it and the ideas developed therein have produced an enormous impact still resounding across disciplines ranging from Computer Science to Economics to Psychology.

Later in his career Professor Holland made further concentrated efforts to help define and promote the field of Complex Systems by speaking internationally, helping to build institutes devoted to complexity in China and Singapore, and writing books for broader academic and public audiences, including Hidden Order: How Adaptation Builds Complexity (1995), Emergence: From Chaos to Order (1998), Signals and Boundaries  (2012), and Complexity: A Very Short Introduction (2014),

Professor Holland was a remarkably interdisciplinary scholar.  He made significant contributions to Artificial Intelligence, Psychology, Linguistics, Neuroscience, and Philosophy.  When the formal field of ‘Cognitive Science’ first came to prominence during the 1970s, Holland was one of the premier co-founders of the Cognitive Science Program at Michigan, collaborating with Professors Gary Olson, Richard Nisbett, David Meyer, and Keith Holyoak.  That program has since evolved into the Weinberg Institute for Cognitive Science with a regular symposium series, an undergraduate major, and a graduate certification.

Another outgrowth of his interactions with psychologists at Michigan was Professor Holland’s 1989 book, Induction, co-written with Keith Holyoak, Richard Nisbett, and Paul Thagard.  In this book, the authors applied Holland’s model of classifier systems for characterizing fundamental aspects of human learning to great effect. 

Professor Holland was also a founding member of UM’s BACH group, whose early members included Bob Axelrod, Art Burks, Michael Cohen, Rick Riolo, and Carl Simon.  That group spawned what is now the University of Michigan Center for the Study of Complex Systems, which offers both a graduate certificate and an undergraduate minor.

Throughout his career, Professor Holland greatly enjoyed engaging with students at all levels. He was a regular participant at graduate and undergraduate reading groups on complex systems, and he taught a popular interdisciplinary course on complexity up until the final year of his life.  

Professor Holland was notable for his passion in all his endeavors, his energy, his love of ideas, his deep cross-disciplinary knowledge, and his generosity. He laughed a lot and he reveled at digging deeply into a subject and unpacking mechanistic explanations.  Stephanie Forrest, a student of Holland’s, writes: "He leaves us not only with a grand intellectual legacy, but with memories of the pure joy he brought to his research, cheerful disregard of academic dogma, and a great sense of fun and mischievousness."

Events honoring John Holland