Charles Dacre Parsons, 91

At a meeting of the Faculty of Arts and Sciences on May 6, 2025, the following tribute to the life and service of the late Charles Dacre Parsons was spread upon the permanent records of the Faculty.

Charles Parsons was a philosopher of logic and mathematics of great penetration, known for clarifying difficult issues, deeply scrutinizing problems of long standing and their attempted solutions, and articulating both judicious proposals to make progress on them and acute analyses of the difficulties that still stood in the way.

Parsons was raised in Belmont, Massachusetts. His father was Talcott Parsons, the eminent Harvard sociologist, and Parsons grew up in a Harvard atmosphere. He was educated at the University, graduating from the College in 1954 summa cum laude in mathematics and entering the philosophy Ph.D. program after a year in Cambridge, England, on a Henry Fellowship. He joined the Society of Fellows in 1958 and completed his Ph.D. and the Junior Fellowship simultaneously in 1961. After three years as an assistant professor at Harvard, he moved to Columbia University, where he taught for 24 years. He returned to Harvard in 1989, becoming the Edgar Pierce Professor of Philosophy in 1991, and retired in 2005.

Parsons’s dissertation and early research work focused on mathematical logic, in which he obtained some noteworthy results in fine-grained analyses of the deductive strength of various axiom systems for areas of mathematics. Subsequently his interests turned towards less purely technical matters, and his writing concentrated on philosophy of logic and of mathematics. In the 1960s and 1970s he published highly influential papers in this area, collected in his first book, aptly titled “Mathematics in Philosophy” (1983). These papers included his careful examinations of the foundations of set theory and of the Liar Paradox, the seemingly paradoxical consequences of the sentence that says of itself that it is not true. The latter, in particular, spawned a large industry of proposed solutions based on Parsons’s work. But perhaps most striking from this part of his career was his attention to Kant. Before Parsons’s work, Kant — whose concern with mathematics is central to his entire philosophical system — had been dismissed as irrelevant to contemporary philosophy of mathematics due to the subsequent development of modern logic, non-Euclidean geometry, and the theory of relativity. Parsons, almost single-handedly, brought Kant back into dialogue with contemporary philosophy of mathematics by locating what was still of interest in his philosophical structures that might be of help in solving the conundrums that contemporary philosophy of mathematics had encountered. To do this, Parsons also made major contributions to pure Kant scholarship, particularly in his exposition of the role Kant’s notion of intuition plays in a crucial section of the “Critique of Pure Reason.”

Parsons’s resuscitation of Kant had a mode of operation in common with all of his work. He never said outright “That position isn’t going to work.” He always carefully drew out what strands in a position might be able to make contributions to current understanding while gently suggesting which other parts were more troublesome.

Parsons’s work in philosophy of mathematics and logic inspired by historical figures was ongoing. Two more collections of his published essays eventually appeared, titled “From Kant to Husserl” (2012), with essays on Kant, Frege, Brentano, and Husserl, and “Philosophy of Mathematics in the 20th Century” (2014), which continued his conversation linking Kant to contemporary philosophy of mathematics but also considered later figures, particularly the pathbreaking logician Kurt Gödel and the Harvard philosopher W. V. Quine, who was one of Parsons’s teachers.

Parsons’s greatest contribution to modern philosophy of mathematics is his final statement of his mature considered views, “Mathematical Thought and Its Objects” (2008). The first half of this volume took off from his seminal paper “Objects and Logic” (1982), which closely examined what it could amount to be a mathematical object. The ultimate result was a sober defense of a view in philosophy of mathematics known as “structuralism,” which argues that there should be no question of what a mathematical entity is but only of what structure it plays a role in. Other contemporaries have defended a view in this neighborhood, but they usually turn out to be implicitly assuming some notion of mathematical entity. Parsons’s work was exemplary in avoiding any such hidden presuppositions, so that his defense of structuralism was the tightest and most convincing. The second half of the book examined epistemological issues, focusing on the role of reason and the room for some notion of Kantian-style intuition in the concept of evidence for a wide range of mathematical theories. Throughout the book, Parsons drew on all his historical work in formulating and appraising various proposed solutions.

Parsons was a devoted graduate teacher. Despite his initial somewhat austere demeanor, his dissertation students at both Columbia and Harvard quickly came to appreciate his kindness and benevolent scholarly attention and became loyal friends. Many of Parsons’s students became major figures in philosophy of mathematics, Kant scholarship, Husserl scholarship, and philosophy of logic and language. Parsons was also well known for a quirk, in both lecturing and informal personal conversation, of pausing in mid-sentence, clearly reflecting on whether what he was about to say was really accurate and, even after a full minute (or even two) of silence, picking up that sentence at the point he had left it.

Parsons was predeceased in 2017 by his wife of 49 years, Marjorie (née Wood). He is survived by their son, Dr. Jotham Parsons (Harvard College Class of 1990); their daughter, Dr. Sylvia Parsons (Harvard College Class of 1992); and two grandchildren.

Respectfully submitted,

Peter Koellner
Christine Korsgaard
Thomas M. Scanlon
Warren Goldfarb, Chair