Charles Sanders Peirce

Charles Sanders Peirce (1839–1914) was an American scientist, mathematician, logician and philosopher, often called the father of pragmatism and one of the founders of modern semiotics, the study of signs. Trained as a chemist, he spent most of his working life as a scientist rather than an academic, and his ideas on logic, inquiry and meaning have gained recognition only gradually.

He was the son of Benjamin Peirce, a Harvard professor of mathematics and astronomy, and he graduated in chemistry from Harvard in 1863. He never secured a permanent academic post. His difficult temperament, a painful nervous condition, the scandal surrounding his second marriage and the opposition of influential figures all worked against him. For nearly thirty years he worked for the United States Coast Survey, on geodesy, gravimetry and pendulum measurements, and from 1879 to 1884 he taught logic part-time at Johns Hopkins University, the only academic appointment he ever held. After retiring he settled in Milford, Pennsylvania, where he wrote prolifically until his death from cancer. He published two books in his lifetime, Photometric Researches and Studies in Logic, but left some 80,000 manuscript pages, much of them unpublished.

Peirce's logic went beyond deduction and induction. He was chiefly interested in how hypotheses are formed, and he called abduction the process by which one proposes an explanation for a surprising fact. He believed this kind of reasoning lay at the heart of scientific research and of everyday thinking. He regarded logic as the formal branch of semiotics, and he hoped philosophy could become a more rigorous, scientific enterprise, even while his own metaphysics remained unusually ambitious.

His pragmatism was not a crude search for profit. For Peirce, the meaning of a concept lies in the general practical consequences we could expect if it were true, and the idea works as a method for clarifying confused notions and testing hypotheses. It went hand in hand with fallibilism, the view that no belief is beyond doubt even though truth can be discovered, and with a picture of the universe in which chance and continuity are real features shaped by an evolutionary process. Because these ideas were so wide-ranging, he was for years hard to classify.

William James acknowledged him as the founder of pragmatism, and his work shaped later debates on logic, language and the philosophy of science. His contributions to the logic of relations and quantification, and to statistics, are now widely recognised. The publication of his collected and chronological writings has made a fuller reading of his thought possible.