Charles Sanders Peirce

Peirce introduced the pragmatic maxim in the late 19th century as a way to clarify ideas by their practical effects. He later used the spelling pragmaticism to distinguish his view from looser versions.

Peirce analyzed signs as a relation among sign, object, and interpretant. This triadic model became central to modern semiotics.

Peirce made important advances in symbolic logic, relations, and quantification. His work overlaps historically with the development of modern logic after Frege's 1879 Begriffsschrift.

Peirce's pragmatism was more tied to logic, inquiry, and scientific method. William James made pragmatism more widely known through lectures and writings around 1900.