Richard Carl Jeffrey (1926-2002) was a member of the Department of Philosophy at Princeton University between the years 1974-1999. Born in Boston, Jeffrey was a naval veteran during the Second World War before earning an M.A. from the University of Chicago in 1952 and later obtained a Ph.D., from Princeton University in 1957. As a student in Chicago and Princeton in the 50’s, Jeffrey was very fortunate to be able to work with the most able exponents in philosophy. Most of his teachers were immigrants, who had participated in the creation of “Logical Positivism” in Vienna and Berlin in the 20’s and early 30’s, which later left Europe due to the rise of Hitler’s influence. Jeffrey worked closely with Rudolf Carnap, researching the probability and statistical bases, and continued his interest in the field of philosophy as a student at Princeton University under the supervision of Carl Gustav Hempel.
Jeffrey’s first academic post after completing his doctoral degree at Princeton in philosophy was an assistant professor of Electrical Engineering at M.I.T. He then became a philosophical instructor at Stanford University, the City University of New York, and the University of Pennsylvania. Jeffrey returned to Princeton Philosophy Department in 1974. He was elected to the American Academy of Science and Literature in 1994, and has served as president of the Philosophy of Science Association from 1999 to 2000.
His first powerful book, titled “The Logic of Decision” was published in 1965. Written when Jeffrey visited the Institute for Advanced Study, it was influenced from his weekly encounter with Kurt Goedel, a well-known mathematical logician in his time. And he has presented a new theory of decision making under uncertainty and probability theory. Jeffrey also wrote two textbooks widely used in logic, namely Formal Logic: Its Scope and Limits (1967), and Computability and Logic (1974), co-authored with George Boolos, and, subsequently, John Burgess. Students from generations to come will master both knowledge, elements and logical extensions by referring the two texts in a highly efficient manner. He also wrote a book titled Probability and the Art of Judgment (1992), Subjective Probability: The Real Thing (2004) and Miscellany of Works on Probabilistic Thinking, a website.
In his life, Jeffrey took into account the ancient view that a philosopher had a special obligation to be happy, and sadness was a form of weakness of the mind. Naturally, Jeffrey is a fit and self-esteemed person. Among his friends, he is known as Diamond Jim. His contributions to the theory of decision, and the sustainability of the Logical Empiricism Programme, Jeffrey was conferred as the most innovative philosopher in the 20th century.