At a meeting of the Faculty of Arts and Sciences on Nov. 7, 2023, the following tribute to the life and service of the late Hilary Whitehall Putnam was spread upon the permanent records of the Faculty.
Hilary Putnam’s influence on analytic philosophy was and remains enormous, ranging widely across fields including mathematical logic, philosophy of science and mathematics, philosophy of mind and language, epistemology, metaphysics, and ethics.
Born in 1926, Hilary Whitehall Putnam spent his first eight years in France; his father, Samuel Putnam, was a noted literary translator and a familiar of the expatriate artistic community. After the family’s return to the U.S., Putnam attended Philadelphia’s Central High School and then the University of Pennsylvania, where he received his bachelor’s degree in 1948. After a year in graduate school at Harvard University, he transferred to the University of California, Los Angeles, where he completed his Ph.D. in 1951 under the supervision of the eminent logical empiricist Hans Reichenbach. Assistant and then associate professor at Princeton University between 1953 and 1961, he was recruited to the Massachusetts Institute of Technology as a full professor in 1961 to head their new philosophy department. In 1965 he moved upriver to Harvard, where he stayed for the remainder of his career.
Putnam’s early work concentrated on philosophy of science and on mathematical logic. In logic, he was a central contributor to the solution of Hilbert’s Tenth Problem, and he co-published the first paper on “fine structure” in set theory with his student George Boolos. In philosophy of science, his criticisms of the logical empiricist analysis of scientific theories and his formulation of the conceptual apparatus to replace it played a major role in the eclipse of the older views. Particularly noteworthy was his idea that different scientific theories could be wildly divergent but, nonetheless, their terms could refer to the same properties. In this way, the theories would still be commensurable, a view diametrically opposed to those of the empiricists and their followers and still debated today.
That view of properties informed Putnam’s revolutionary work in the philosophy of mind. His 1960 paper Minds and Machines formulated the position he dubbed “functionalism,” in which human mental states are taken to be realizations of the internal states of a computational device whose characteristics are given through the links they forge between inputs and outputs. According to this view, mental properties are identical to computational properties, even though we talk about them in very different ways. Functionalism became the dominant view in philosophy of mind and cognitive science for decades and is still widely maintained.
Putnam’s most far-reaching work lay in philosophy of language, where he originated semantic externalism: the reference of our words is not determined by features that are cognitively available to us but by facts of the external world that we may know nothing about. In support of this view, Putnam proposed the thought-experiment of Twin Earth: imagine a planet much like ours on which there is a common substance that looks, smells, and tastes like our water, so that it plays the same role in daily life outside the laboratory yet has a chemical composition different from H2O. Putnam argued that the denizens of that planet would refer by their word “water” to that different substance but not to our water, even though their mental and linguistic representations surrounding the word would be the same as ours. Twin-Earth-style examples have since become a staple of philosophy.
Putnam’s views were not constant: he had a reputation for frequently changing his mind. For example, 28 years after he proposed functionalism, he published a book that argues against it. Some of the most visible changes were in his stance in metaphysics. At first, he championed what he called “scientific realism.” In the mid-1970s, feeling that such a view licensed existence assertions that were too remote from the evidence for them, he proposed what he called “internal realism.” Subsequently, he judged that he had moved too far in the direction of verificationism and rebounded with a view he called “pragmatic realism,” but he later found this insufficiently robust and replaced it with “common-sense” or “naive” realism.
These evolving takes on realism were paralleled by Putnam’s search to integrate the scientific point of view that permeated his earlier thinking with historical and humanistic knowledge. This progression is reflected in the titles of his books of the 1990s such as “Realism with a Human Face” and “The Threefold Cord: Mind, Body, and World.” During this time, he also became religiously observant and concerned in a scholarly way with Jewish tradition, resulting in his 2008 book, “Jewish Philosophy as a Guide to Life: Rosenzweig, Buber, Levinas, Wittgenstein.” The same concerns, in a secular setting, are reflected in his 22nd and last book, the posthumously published “Pragmatism as a Way of Life: The Lasting Legacy of William James and John Dewey,” co-authored with his wife Ruth Anna Putnam, a professor of philosophy at Wellesley College.
One traditional topic became prominent in Putnam’s later work. He argued against the notion that there is a sharp distinction between facts and values, between “is” and “ought.” That distinction was orthodoxy in philosophy, going back at least to Hume. For Putnam, in contrast, fact and evaluation are inextricably entangled. Hence there can be no impugning the objectivity of evaluative discourse while accepting factual, scientific knowledge.
Putnam retired from teaching at Harvard in 2000, although he remained professionally active until his final year. He was survived by his wife; two daughters, Erika Putnam Chin and Maxima Kahn; two sons, Samuel and Joshua; and four granddaughters.
Edward J. Hall
Charles D. Parsons
Thomas M. Scanlon
Warren Goldfarb, Chair