We were profoundly sad to learn the Aldo Antonelli prematurely passed away on October 11, 2015. He was the nicest person and an outstanding philosopher of mathematics and logic. 

We at the FilMat Network are extremely indebted to him for his precious participation to our first conference and for his continuous support to our activities. It is a great loss for all of us.

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Gian Aldo Antonelli received his undergraduate degree (Laurea) from the University of Turin in 1986, at the age of 24. In the course of his studies, he wrote a thesis on the philosophy of language, supervised by Diego Marconi, and at the same time developed a keen interest in mathematical logic, thanks in part to his teacher Gabriele Lolli. After a brief period at Olivetti, he decided to pursue a course of graduate education in philosophy and logic in the U.S.A. He subsequently received his doctorate from the University of Pittsburgh in 1992, under the supervision of Nuel Belnap, with a dissertation on non-monotonic logics. He went on to teach at various universities in Connecticut, Pittsburgh, Yale, Stanford, Michigan, UC Irvine, and UC Davis. During the period 2004-2006, he returned to Italy to direct the Rome/Siena Study Center of the University of California.

He is the author of an impressive number of scholarly articles, many in the leading international journals of logic and philosophy of logic and mathematics, including the Journal of Symbolic Logic, the Journal of Philosophy, the Notre Dame Journal of Formal Logic, Philosophia Mathematica, and Synthese. He was an active member of the Association of Symbolic Logic and a founder of its most recent journal, the Review of Symbolic Logic. He also helped to found (with great passion and commitment) the Italian network for the philosophy of mathematics, FilMat.

He contributed significantly to the study of non-monotonic and free logics, as well as that of generalized quantifiers and the axiomatization of game theory. He also contributed significantly to the revitalization of Frege’s program for the foundations of arithmetic. His article “Frege’s Other Program” (Notre Dame Journal of Formal Logic, 2005), written with his friend and colleague Robert May, remains essential reading for anyone interested in understanding how arithmetic could be grounded on a theory of concepts using an extension of second-order logic. He did not, however, embrace the neo-logicist perspective.

Discussing logic and philosophy with him was an enormous pleasure. He knew how to focus on what was essential, with the clarity of someone who could master intricate technicalities at a glance, but to move beyond this technical understanding, though using it, when necessary, as a means to explain and describe. He was never satisfied with an answer until he had completely understood the underlying problem in all its detail.

Aldo was sincere and generous with his time and his knowledge. He was also affectionate and calm, witty, and always a genuine friend. A short while ago, he realized a long-held dream of owning a white, powerful Moto Guzzi motor-bike, of which he was very proud and with which he was looking forward to exploring California and places beyond. He moved to UC Davis to be close to his partner, with whom he shared his passion for philosophy of mathematics and logic.

Aldo’s zest for life, his will to understand, his teaching, his desire to help others become better teachers, and the nature of his friendship, will all be remembered. We pass on our sincere condolences to his partner, Elaine, and to his brother David, sons Federico and Riccardo, and their mother Giovanna Fogli.