Peirce he was trying to get a university professorship to teach logic, but only got temporary assignments. For twenty years, between 1864 and 1884, he taught courses in logic at Johns Hopkins University in Baltimore, the Lowell Institute in Boston, and Harvard University.
Of great importance are his writings on logic in which he develops the themes of George Boole’s algebraist current with an original calculus of relations – Peirce he based his research on the development of Boolean algebra – as well as Augusto De Morgan.
In 1891 he received a small inheritance and took the opportunity to retire to the city of Milford where he would spend the last years of his life in isolation and poverty; left many important manuscripts in many areas of philosophy. In Milford, Charles Sanders Peirce died April 19, 1914.
Peirce he wanted to distinguish himself from James whom he accused of having impoverished pragmatism to the exclusion of its logical-semiotic foundation, considered the key part of a theory of knowledge. The current of pragmatism is the most original American contribution to the philosophy of the twentieth century and would exert a vast influence also on European culture: the term “pragmatism”, in short, emphasizes the fundamental thesis that the meaning of anything is determined by its practical relevance.
The works of Peirce they are contained in a collection of writings with his signature, published in 1931 (“Papers of Ch.S. Peirce Collected”).
Peirce, also for his contributions to logic and epistemology, is remembered as an important scholar and is considered the founder of pragmatism as well as the father of modern semiotics. In the last decades, his thinking was strongly revalued to place him among the main innovators in many fields, especially in the methodology of research and the philosophy of science.