The Polish-American mathematician and logician Alfred Tarski (1902-1983) is regarded as the cofounder of metamathematics and one of the founders of the discipline of semantics.

Alfred Tarski was born in Warsaw on Jan. 14, 1902. He taught at the Polish Pedagogical Institute from 1922 to 1925, and in 1924 he received his doctorate in mathematics from the University of Warsaw. He became an adjunct professor at the University of Warsaw in 1925. He married Maria Josephine Wilowski in 1929, and they had two children.

Tarski's mathematical contributions were noteworthy. In 1924 he collaborated with S. Banach in establishing the theorem on the decomposition of the sphere. In 1938 he presented an important paper on inaccessible cardinals and wrote another paper on the same topic in 1964 with H. J. Keisler. Tarski employed algebraic tools to treat metamathematical problems, as evident in his work on cylindric algebras (1961) written with Leon Henkin.

Like most mathematicians, Tarski simply accepted the assumptions...