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Kotaro Suzumura

Kotaro Suzumura (January 7, 1944 – January 15, 2020) was an exceptional person in a league of his own. His contributions to economics in general and to social-choice theory and welfare economics in particular were path-breaking and unparalleled. In addition to his own research, Kotaro single-handedly created an entire community of excellent scholars who are dedicated to normative economics and the theory of collective decision-making. Japan is now a powerhouse in our field—an achievement that would not have been thinkable without him.

I trust that everyone reading this piece is familiar with Kotaro’s superb academic record and I will therefore refrain from providing an account of his stellar accomplishments. Please allow me to instead indulge in some personal reminiscences, in the hope that I will at least partly succeed inconveying what an extraordinary and gentle human being Kotaro was.

I enjoyed several brief encounters with Kotaro at various conferences during the late 1980s and early 1990s but it was not until the late 1990s that I had the opportunity to discuss research of mutual interest with him in person. I had a position at the University of Nottingham at the time and Kotaro was visiting our department, primarily to work with his coauthor Yongsheng Xu. In the course of our exchanges, it became clear that Kotaro and I had been thinking about the same research questions for some time, and it was only natural that we decided to combine our efforts. Along with my colleague Yves Sprumont (whom we had the good fortune of counting as a collaborator on several joint projects), I visited him at Hitotsubashi University for the first time in 2000. This sparked our collaboration which flourished and continued until the very end.

It was a pleasure and a privilege to have Kotaro as my sensei, as my coauthor and, above all, as my dear friend for more than two decades. He was my guide and my companion during numerous visits to Japan. I don’t have the words to adequately describe how much I learned from him, both as a social-choice theorist and, more importantly, as a person. I will never forget the hours we spent discussing everything under the sun, sharing meals, exchanging reading recommendations, or watching baseball together.

Kotaro introduced me to genuine Japanese cuisine and, over the years, we kept going back to the same restaurants. We had our favorite tempura place, our regular sushi restaurant, and what must have been one of the best soba establishments in Tokyo. Kotaro taught me how to order bıru in nihongo and, after satisfying himself that I had reached the requisite proficiency, permitted me to graduate to nama bıru before, at long last, reaching thepinnacle of nama dai. Moreover, I owe my first fugu experience to him. And I greatly enjoyed Kotaro’s anecdote that he once had the dubious honor of being the first customer (or shall I say guinea pig?) of a friend of his who had just obtained his license as a fugu chef; apparently the ink on the document was barely dry by the time he demonstrated his skills in narrowly avoiding the potentially lethal poison sac that is characteristic of the sea dweller in question.

At some point we discovered that we shared a fondness of crime and mystery novels. One evening at a French restaurant in Montreal, we started talking about books that we had read and enjoyed, and trading suggestions for authors became a regular fixture during our increasingly enjoyable mutual visits.

On at least one occasion, Kotaro visited me while the World Series was in progress and we managed to catch an unforgettable match that went into extra innings. Spending these four hours in front of my TV with him was a sheer joy; his excitement and his delight were nothing short of infectious. Kotaro was a walking baseball encyclopedia. He literally knew everything about the game that was worth knowing—and his expertise covered both the Major League and the Nippon Professional varieties.

Kotaro was in Montreal when the earthquake and tsunami hit on March 11, 2011. Confronted with this tragic event, his great compassion came to the fore. He showed boundless concern for his loved ones and all those affected. His dedication to do, even from afar, everything in his power to help in any way possible was truly remarkable and filled me with deep admiration.

One of Kotaro’s many outstanding contributions that I appreciate the most is his “Remarks on the Theory of Collective Choice,” published by Economica in 1976. Although I promised earlier to control my urges to discuss his research in detail, I feel compelled to mention this particular article because it is indicative of what I think of as his exceptional personal qualities. Evidently, the title of this piece couldn’t be any more modest. And yet, the paper contains some deep and original results that are of profound importance not only in our field but also in mathematics. In addition to providing a substantial generalization of Edward Szpilrajn’s celebrated extension theorem, this is where Kotaro introduces his path-breaking notion of consistency. After many years of exploring this ingenious weakening of transitivity and its possible ramifications, I came to the conviction that it is more natural and fundamental than transitivity itself; as I see it, all transitivity has to say for itself is that it is equivalent to Suzumura consistency in the presence of reflexivity and completeness. But I digress; the point I want to make is that it says so much about Kotaro that he chose such a humble label for this work of beauty. To me, it is an attribute of great wisdom to be aware of how little it really is that we know—and to express genuine humility in the face of this realization.

As we all know, social-choice theory is not exactly the most popular subject these days (to put it mildly). Even an intellectual giant of Kotaro’s stature had to suffer more and more from having his work desk-rejected solely on the basis of his choice of research topic. He never let the—at times quite hostile—responses of this kind bring him down and persevered with great determination and an unshakable belief in the importance of our field.

I am sure he would want us to follow in his footsteps and resist this unfortunate bias that seems to be creeping into the editorial offices of an expanding set of journals. Perhaps one of the best ways of honoring his memory is to make sure that we do not allow ourselves to get discouraged and continue to do—and proudly promote—the research that we are so fond of.

Kotaro had a profound and lasting impact on my life. His tremendous courage and his genuine desire to make this world a better place was a true inspiration and permeated all his endeavors, be they of a professional or a personal nature. I am a better human being because of him and I am sure that he had the same effect on countless others.

In these dark hours dominated by grief, I find solace in Kotaro’s leaving us with the legacy of his example. Kotaro was a truly great and graceful person with a big heart and unsurpassed generosity and kindness. He will be sorely missed but my fond memories of him will live on forever in my heart.

Farewell, my dear friend, and rest in peace.

Walter Bossert


Society for Social Choice and Welfare
Université de Caen Basse Normandie
14032 Caen Cedex, France

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