Henry Maurice Sheffer, An American logician (Mathematician)

Henry Maurice Sheffer

Henry Maurice Sheffer, an American logician born at Ukraine in year 1882. Henry M. Sheffer was a Polish Jew, who migrated to the USA in year 1892 with his parents. Before higher studies Sheffer studied at Boston Latin School. For higher studies, he took admission in Harvard University and learned logics from Josiah Royce. He completed his undergraduate and master’s degree in year 1905 & 1907. After that he did Ph.D. in Philosophy in year 1908 and then travelled on a fellowship program to Europe. After returning to USA, he spent one year each at City College of New York, University of Misouri, University of Minesota, University of Washington, and University of Cornel as an academic nomad. In year 1916, Sheffer recruited at Harvard University as a faculty member of philosophy department. He worked at Harvard University for 36 Years and got retirement in 1952.

Shaffer was very dedicated in teaching mathematical logics. He likes small strength classes and never likes to appear strangers in his classroom. If strangers appear, he would order them to leave. Sheffer was 5 feet tall and noted for his vigor and wit but also for his irritability and nervousness. He mostly liked to be quite at lonely place. He spoke a quote at the time of his retirement that: “Old professors never die, they just become emeriti.” Sheffer was a married person and lived most of his life in a small packed room with his logic books and vast paper files noted with his ideas. During last two decades of his life, he suffered from severe depression.

In year 1913, Sheffer defined Boolean algebra by using a single primitive method of binary operation, abbreviated as NAND and its dual called NOR, in the meaning of neither nor. Similarly, with the use of single connective by the truth table of either NAND logic, propositional calculus could be formulated, called Sheffer stroke usually symbol with vertical line. These facts also discovered by the Charles Peirce in year 1880, but the appropriate paper was not published up to 1933.

Sheffer stroke introduced by the Henry Maurice Sheffer in year 1913, which became well known when used in the Russell’s Principia Mathematica and Whitehead edition of 1925. The discovery of Sheffer won the great commendation from Bertrand Russell, who used the Shaffer’s discovery to simplify his own logic, in the 2nd edition of Mathematica. Sheffer was a mystery man to logicians, especially because he didn’t publish too much in his career. He always describes his methods in mimeographed notes or in a brief published abstract instead of publishing the detail of method. Mathematical Logic of W.V. Quine’s was also much made with the help of Sheffer stroke.