Peirce's theory of signs
Origin of Species was published; he approached the end of his life just before Albert Einstein presented us with General Relativity. His lifetime saw the emergence of psychology as a discipline separate from philosophy, a birth attended by philosopher-psychologists such as his good friend William James. The work of Peirce, like that of the other American Pragmatists, reflects the ferment of the times. His thought bears the imprint of science, not the science of that Nineteenth Century which as Loren Eiseley has remarked, "regarded the 'laws' of nature as imbued with a kind of structural finality, an integral determinism, which it was the scientists’ duty to describe," (Eisele, 1971) but rather, of science as open, as intrinsically revisable, as radically empirical. Working from the model of science in this latter sense, Peirce held that philosophy, and indeed logic..