This paper examines the contemporary philosophical and cognitive relevance of Charles Peirce's diagrammatic logic of existential graphs (EGs), the ‘moving pictures of thought’. The first part brings to the fore some hitherto unknown details about the reception of EGs in the early 1900s that took place amidst the emergence of modern conceptions of symbolic logic. In the second part, philosophical aspects of EGs and their contributions to contemporary logical theory are pointed out, including the relationship between iconic logic and images, (...) the problem of the meaning of logical constants, the cognitive economy of iconic logic, the failure of the Frege–Russell thesis, and the failure of the Language of Thought hypothesis. (shrink)

Among the many problems posed by Peirce's concept of abduction is how to determine the scope of this form of inference, and how to distinguish different types of abduction. This problem can be illustrated by taking a look at one of his best known definitions of the term:Abduction is the process of forming an explanatory hypothesis. It is the only logical operation which introduces any new idea; for induction does nothing but determine a value, and deduction merely evolves the necessary (...) consequences of a pure hypothesis.The second half of this quote is not part of the definition, but an explanation of it. However, it adds something to this definition because it says implicitly that there are only three logical.. (shrink)

Peirce’s system may be identified as one of a family of “organic memory” theories which flourished during the period in which he developed it, especially in the Monist journals which published much of his late work. “Organic memory” theories were vigorously opposed in their own day and are remembered in our own, if at all, only in connection with discredited theories such as racial memory and Lamarckian inheritance. When read in the context of their own time, however, “organic memory” theories (...) stand revealed as among modernity’s first attempts at a still-unrealized, post-nominalist re-foundation of science. Being thus closely related to Peirce’s own project both in time and in spirit, they deserve to be understood on their own terms. The synthesis of these theories in the book Das Gesetz der Serie (1919) by the Austrian biologist Paul Kammerer (1880-1926), a prominent representative of organized Monism's European branch, provides insight into the systematic unity of the various aspects of Peirce's thought, especially the close relationship between pragmatism and what is now called “emergence.”. (shrink)