C. S. Peirce

The 20th century philosopher Charles Sanders Peirce is America's greatest thinker so far. He was a logician, specialized in semiotics, a realist, renouncer of Kantianism, and was vigorously anti-Cartesian. See:

• C. S. Peirce's 5 famous The Monist papers
• John N. Deely's "Charles Sanders Peirce and the Recovery of the Signum" and "The Impact of Semiotics on Philosophy"
• Arisbe: The Peirce Gateway
• Dictionary of Peirce's Terms
• Institute for Studies in Pragmaticism
• Peirce.org
• physicist Peder Voetmann Christiansen's papers on applying Peirce's thought to physics (quantum semiotics)
• cf. also A Triadic Theory of Elementary Particle Interactions and Quantum
• and the related U.S. Patent 6819474.