NAGEL, Ernest

(b. 16 November 1901 in Nové Mesto, Bohemia; d. 20 September 1985 in New York City), one of the United States' most prominent philosophers of science, whose 1961 book Structure of Science was considered a defining work in the logic of scientific explanation.

Nagel, one of two children in an immigrant family, was born in an area that is in today's Czech Republic. His parents were Isadore Nagel, a businessman, and Frida Weiss Nagel. The family arrived in the United States in 1911, and Nagel became a U.S. citizen in 1919. In 1923 he received his bachelor of science degree in social studies from the City College of New York. He pursued his master's and doctoral degrees in philosophy at Columbia University, receiving them in 1925 and 1931 respectively. Between 1923 and 1929 he taught physics in New York City public schools. Nagel moved on to City College of New York as an instructor in 1930, and in 1931 he began teaching philosophy at Columbia University. In 1935 Nagel married the physicist Edith Haggstrom, with whom he had two sons. With the exception of the year 1966–1967, when he taught at Rockefeller University, Nagel stayed at Columbia until his retirement in 1970. He continued to give seminars at Columbia and remained strongly connected to it until his death in 1985.

At Columbia, Nagel became part of a core group of naturalists, philosophers who believed that only nature, without the assistance of supernatural powers, was responsible for the laws of science and society. At City College he was trained by Morris R. Cohen, with whom he published Introduction to Logic and Scientific Method in 1934. The book was immensely successful and remained one of the most influential in the field well into the 1950s. Following a year of study in Europe, Nagel published "Impressions and Appraisals of Analytic Philosophy in Europe" in the Journal of Philosophy (1936). This work introduced logical positivism—the marriage of empiricism and linguistics—to American philosophers.

In 1961 Nagel published his most famous and widely read book, The Structure of Science. This book, which discusses the logic of scientific explanation, is still considered one of the most definitive works in this area of the philosophy of science. Nagel first discussed four types of scientific explanation: deductive, where the explanation follows logically from the premises of the argument; probabilistic, where the explanation is probable given the premises; teleological(functional), where the explanation defines the function or goal of what is explained or studied; and genetic, meaning historical, where the explanation relies on earlier knowledge to explain the studied object. The Structure of Science clearly and methodically examined the problems in the logic of the various methods of scientific explanation. The book also examined the nature of scientific theories and attempted to show that all scientific theories, including those in the social sciences, can be explained by the same empirical methods usually associated with the physical sciences.

The 1960s were a tumultuous time. Conflict raged around the globe, while in countries such as the United States and England student movements were calling for a change. Science itself was swiftly changing, with new discoveries and better understanding of the living world. In that climate of radicalism, philosophy itself was undergoing a fundamental transformation. It is a testament to Nagel's clarity of style and logic that his book remained as respected as it did. The philosophy of logical positivism was fast becoming outdated in people's minds. A year after Structure of Science was published, Thomas S. Kuhn published The Structure of Scientific Revolutions (1962). The book became a best-seller.

Like the decade in which it was published, Kuhn's book departed radically from traditional thought. While Nagel and others saw science as progressing in a logical fashion, each discovery building on previous knowledge gained, Kuhn espoused the idea that science progresses in fits and starts, "a series of peaceful interludes punctuated by intellectually violent revolutions … the tradition-shattering complements to the tradition-bound activity of normal science." Following these revolutions, "one conceptual world view is replaced by another." Kuhn referred to each worldview as a paradigm. His use of the term paradigm popularized it for generations to come. Kuhn opened the floodgates of the New Philosophy of Science, a modern school of thought whose main proponents were Paul Feyerabend, Norwood Russell Hanson, and Imre Lakatos. The New Philosophy was fast replacing logical positivism and naturalism.

In a decade that saw a growing antagonism toward traditional philosophies often perceived as intolerant, the respect in which Nagel was held speaks to his open-mindedness. Kuhn's book was more appealing in a world filled with scientific revolutions and political unrest, but Nagel's willingness to criticize, as Patrick Suppes points out, "ill-conceived notions from whatever quarters they might come" made him an inspiration to students not only of philosophy but of other disciplines as well. It did not hurt that Nagel also was involved in the changing world around him, writing for the Nation and Partisan Review. While his brand of philosophy was falling out of favor in the 1960s, he himself remained relevant.

Nagel's vast knowledge of science set him apart from other philosophers of science. He had an intense interest in physics, which he continued to pursue after retirement, and he conducted a regular seminar on methodology in social sciences. In 1978 he was elected to the National Academy of Sciences, not a common occurrence among philosophers. In his long and distinguished career he won numerous honors and awards. Among them were Columbia University's Nicholas Murray Butler Medal in Gold (1980); an honorary doctor of science degree from Brandeis University; and doctor of letters degrees from Rutgers University (1967), Case Western Reserve University (1970), and Columbia University (1971). He served as president of the American Academy of Arts and Sciences from 1961 to 1963. In addition to publishing in various philosophical journals, Nagel was editor of the Journal of Symbolic Logic (1939–1945), Journal of Philosophy (1940–1956), and Philosophy of Science (1956–1959). He died of pneumonia and is buried in South Wardsboro, Vermont.

Biographies of Nagel include Patrick Suppes, "Ernest Nagel," Biographical Memoirs of the National Academy of Sciences, vol. 65 (1994): 257–273; Antony Flew, "Nagel, Ernest," in The Encyclopedia of Unbelief (1985); and Andrew Reck, The New American Philosophers: An Exploration of Thought Since World War II (1968).

Adi R. Ferrara