Today I learned that John Holland passed away. John was my “grand advisor”, as he was the Ph.D. advisor to Stephanie Forrest, my Ph.D. advisor. Thus while I had only met John briefly, his work has profoundly influenced my own.
What most impresses me about John’s work is his clear dissatisfaction with his past work. He developed genetic algorithms and could have spent his entire career on them; yet he went on to develop other major systems such as learning classifier systems and Echo. John understood that the models of biology that he gave to computer science only captured small fragments of the richness of living systems; thus, while others have spent their careers elaborating on his past work, he kept working to capture more of that richness. He knew how far we had to go.
The world is poorer for losing his future insights.