Born Sept. 10, 1839, in Cambridge, Mass.; died Apr. 19, 1914, in Milford, Pa. American idealist philosopher, logician, mathematician, and natural scientist. Member of the American Academy of Arts and Sciences (1877) and of the National Academy of Sciences (1879).

Son of the well-known American mathematician B. Peirce, Charles Peirce graduated from Harvard University in 1859. From 1866 to 1891, he was on the staff of the United States Coast and Geodetic Survey. He lectured on logic, history, and the philosophy of science at Harvard University, Johns Hopkins University in Baltimore, and elsewhere.

Peirce’s philosophy combines two contradictory tendencies: the empirical and positivist tendency that derives from Kantian “criticism” and the objective-idealist tendency associated with Plato and F. W. Schelling. The basic scheme of Peirce’s ontolog-ical constructions is expressed by the following thesis: “Spirit is first, matter is second, and evolution is third.” Peirce criticized agnosticism, saying that an incognizable but real thing-in-itself is inherently contradictory. Yet at the same time he denied certainty of knowledge: “All our knowledge floats in the continuum of weak semblances and vagueness.”

Peirce gave primary importance to the problem of formation, reliability, and validity of scientific knowledge and opinion. In his view, the problem can be solved only if meaning is interpreted exclusively in terms of results: “Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have. Then, our conception of those effects is the whole of our conception of the object” (Collected Papers, vol. 5, Cambridge, Mass., 1934, paragraph 402). This principle of Peirce’s received further development in the idealist conceptions of pragmatism; indeed, the term “pragmatism” was introduced into philosophy by Peirce. Thus, following Peirce, W. James went on to identify truth directly with practical results, with utility.

Peirce’s principal achievements were in mathematical logic and semiotics. In mathematical logic, he investigated the concept of degree of confirmation, worked on the classification of propositions and arguments, studied the nature of logic and the relationship between logic and mathematics, investigated the limits and possibilities of formalization, and discovered minimal systems of logical operations through which the remaining operations can be expressed. Semiotics, which studies all sign systems used in human collectives, was essentially created as a science by Peirce.