The German mathematician and philosopher Gottlob Frege (1848-1925) is considered the founder of modern mathematical logic. His work was almost wholly ignored during his lifetime but now exerts a great influence on the philosophy of logic and language.

Gottlob Frege was born on Nov. 8, 1848, at Wismar. He began his university studies at Jena in 1869 but after 2 years moved to Göttingen. He studied mathematics, the natural sciences, and philosophy and took his degree in 1873. Thereafter he taught at Jena in the department of mathematics. He was made a professor in 1896 and retired in 1918. Frege was married to Margarete Lieseberg, and the couple had one adopted son. Frege died on July 26, 1925, in Bad Kleinen.

Frege invented the concept of a formal system of mathematical logic, and in his first major work, Begriffsschrift (1879), he presented the first example of such a system in his formulation of a propositional and...