Charles Sanders Peirce (18391914) was an American philosopher, logician, and scientist. He is the founder of pragmatism and of modern semiotics as a formal discipline.

Core ideas

  • Triadic sign theory: a sign is a three-place relation among a representamen (sign vehicle), an object, and an interpretant. This triadic structure distinguishes Peirce’s semiotics from Saussure’s dyadic model.
  • Pragmatism: the meaning of a concept is the sum of its practical consequences. Peirce later renamed his position “pragmaticism” to distinguish it from William James’s popularization.
  • Abduction: a third mode of inference alongside deduction and induction — the generation of explanatory hypotheses. Peirce considered abduction the engine of scientific discovery.
  • Categories: Firstness (quality, possibility), Secondness (reaction, brute fact), Thirdness (mediation, law, habit). These categories structure Peirce’s classifications of signs.
  • Unlimited semiosis: interpretants are themselves signs, producing further interpretants in an open-ended chain of meaning.

Notable works

  • Collected Papers of Charles Sanders Peirce (8 volumes, published posthumously)
  • “On a New List of Categories” (1867)
  • “How to Make Our Ideas Clear” (1878)
  • “A Guess at the Riddle” (c. 1890)
  • sign — the central concept of his semiotic theory
  • interpretant — the meaning produced by a sign
  • semiosis — the process of sign-mediated meaning-making