In 1969, I came to Edinburgh for the Machine Intellegence Workshop, where Donald Michie introduced me to a young graduate student named Gordon Plotkin, whom he described as "brilliant". So when Gordon began to speak, I listened carefully with my innocent American ears - and quickly concluded that Gordon must indeed be brilliant, since I could hardly understand a word.
Since then, my ears have grown more sophisticated, Gordon's accent has become more subtle - and he has more than justified Michie's characterization.
At that time, the two of us shared a common interest in dualizing resolution. I'd discovered a simple algorithm for antiunification, but Gordon had gone far beyond me in exploring the clausal level, in what became his thesis on inductive reasoning.
Note that this thesis was in Artificial Intelligence, and that we had met at a meeting devoted to AI. Nowadays this seems strange, but at the time it did not. Computer Science then was like the first moment of the big bang. Everything was tightly connected, everybody knew everybody else's research, and researchers careened from one area to another - areas that would be considered separate fields of study today.
What is special about Gordon is that he has continued to careen in this way throughout his career, while doing work of the highest quality and originality. I suspect that, if I were to ask each of you here to name your favorite paper of Gordon's, we would amass a list containing most of his papers.
Another way of saying much the same thing is that nowadays each researcher inhabits a particular apple tree, whose low-lying apples have already been picked, so that he must be an accomplished climber to reach the few apples that remain. But in the 50's and 60's, the great researchers were those who could spot new trees. Somehow, we had stumbled into a mysterious forest, full of wonderous but barely visible flora.
And somehow Gordon has retained this ability to spot new trees, and has brought us a bountiful harvest.
So I propose a toast to Gordon Plotkin: Thank you for all you have given us. Happy birthday, young man. And keep up the good work.
- John C. Reynolds