SHEFFER, HENRY M.

SHEFFER, HENRY M. (1883–1964), U.S. logician. Born in the Ukraine, Sheffer was taken to the U.S. at the age of 10. After teaching in various institutions, he was appointed to Harvard in 1916 and became a professor there in 1938. Though Sheffer wrote little, he had many seminal ideas which exerted their influence on the development of symbolic logic through the outstanding logicians whom he trained, including William Van Orman Quine and Susanne K. Langer. His method of working was through a critical exposure of fallacies and then a demonstration of how they could have been avoided. He also stressed the importance of the way the basic postulates of a system are set out, an idea which proved fruitful as much in general philosophy as in logic itself. In 1913, Sheffer published a paper showing that all Boolean functions could be expressed in one primitive term, the Shefferstroke function. (C.S. Pierce had discovered this but never published it.) Though most of his ideas were only suggested, Bertrand Russell and Alfred North Whitehead were impressed by Sheffer's originality, and in 1925 said his work "would demand a complete rewriting of their Principia Mathematica." A volume of essays, Structure, Method, and Meaning (New York, 1951) was published in his honor. -BIBLIOGRAPHY: F. Frankfurter, in: P. Henle et al. (eds.), Structure, Method and Meaning (1951), xv–xvi. (Richard H. Popkin)