Hilary Putnam, Cogan University Professor Emeritus in the Department of Philosophy at Harvard, was one of the most influential philosophers of our time. His extraordinarily wide-ranging contributions, spanning 24 books and over 300 articles, are unusual not only because of their originality, but also for a fearless habit of criticising and rethinking his views. This radical practice of philosophy also brought him into conversation with numerous philosphers, giving an unmatched breadth to his work. He was also unique in his ability to re-set the research agenda in key areas of philosophies of science, mathematics, language and mind.
In 1927, when Hilary was six months old, the family moved to Paris where his father, Samuel Putnam, translated the works of Rabelais and edited the literary magazine The New Review. Putnam grew up in the cosmopolitan artistic world of Gertrude Stein, Hemingway, Ezra Pound, Elliot, Joyce, and Ford Madox Ford. His upbringing contributed to a distaste for the narrowness and insularity of much of contemporary philosophy. The blog Sardonic Comment, which he launched in 2013 and kept going until the onset of ill health in October 2015, is a testament to his commitment to inclusivity.
Putnam’s earliest writing focused on philosophy of mathematics and science. Two central arguments, the “indispensability argument” in philosophy of mathematics and the “no-miracle argument” in philosophy of science, advance the claim that we are unable to explain the successes of scientific theories unless we assume that they provide true accounts of how things stand in the world. Both arguments remain central to philosophical discussions of science and mathematics. In addition to his philosophical work, Putnam’s co-publication with M. Davis and J Robinson, of a proof of Hilbert’s Tenth Problem, established him as a major figure in mathematics, giving further support to the claim by many, including his life-long friend Noam Chomsky, that he was one of the finest minds of our time.
Putnam's most influential contributions are to philosophy of language and mind. The approach known as "semantic externalism" – the view that meanings are not subjective, or 'in the head' as he puts it, but are determined by the objects and events of the social and natural world – continues to dominate debates on language and thought. His imaginative use of thought experiments, most famously the "Brains in a Vat" thought experiment, where he uses semantic externalism to undermine the sceptical challenge that we might be just brains in a vat of nutrients, have inspired not only generations of philosophers but also the popular movie The Matrix.
In philosophy of mind, his theory of machine-functionalism, the view that human mental states are computational states, played a transformative role, not only in philosophy, but also in the developing fields of artificial intelligence and cognitive science. Later, Putman rejected the view that human thinking could be simply identified with computational states and advocated what he called a “non-reductionist” Aristotelian functionalism.
Ethical questions have always been central to Putnam’s life and thought. They are, indeed, what motivated his political and anti-war activism of the late 1960s, as well as his turn to Judaism, the ancestral religion on his mother’s side, in the 1970s.
Putnam’s main contribution to ethical thinking was his rejection of the traditional division between matters of fact and questions of value. Since David Hume in the 18th century, the so-called “fact/value dichotomy” has dominated the thinking about science and ethics. Putnam believed this to be a wrong starting point for understanding either science or ethics. In the 2007 Agnes Cuming lectures at University College Dublin, and in various publications, he argued that all cognition presupposes value judgments and that moral judgements, in turn, are not free of facts: facts and values interpenetrate. Throughout the many changes of positions, this aversion to dichotomised thinking remained a constant feature of Putnam’s work allowing him, in his most recent writings, to combine a profound appreciation of the natural sciences with an acknowledgement of the plurality of human interests and perspectives.
Hilary Putnam was a frequent visitor to Ireland. His numerous awards included the Ulysses Medal from University College Dublin and an Honorary Doctorate from the National University of Ireland. His 80th birthday was celebrated in UCD through an international conference attended by many of his prominent former students. Those who knew him remember not just the brilliance of his mind but also his unmatched kindness and generosity.
He is survived by his wife Ruth Anna Putnam, a well-known philosopher in her own right and a frequent collaborator, and by his four children, Erica, Polly, Sam and Josh, and four granddaughters.