‘Abduction’ was the term Charles Sanders Peirce used in his later writings for a type of inference that he had earlier called ‘hypothesis’ and that is now commonly called ‘inference to the best explanation’. According to Peirce, abduction constituted, alongside induction, a distinct second form of nondemonstrative or probabilistic inference. Especially in his later work, Peirce conceived of abd...

A major advantage of conceptual graphs is their ease of use in the graphical form. This paper is intended to present some general guidelines for building a suitable conceptual graph interface and the details of a particular implementation currently under development. The resulting software is to be completely integrated with the existing PEIRCE code, built to conform with the PEIRCE standards o...

This paper aims to enhance the practical applicability of relational grammars, which have been devised for the semantic analysis of natural language. We focus on their application in knowledge representation. In particular, we address how the representation problem for kl-one-based knowledge representation systems can be automatically solved with the help of relational grammars. New rules are p...

Nowadays, Peirce is mostly recognized as the founder of pragmatism and for his extensive theory of signs. Interestingly, in contrast to the contemporary estimation of his work, Peirce himself considered his system of existential graphs as the ‘luckiest find of my career’. This paper aims to clarify why Peirce placed his existential graphs into the very heart of his philosophy. Moreover, the des...

In the program article ―The Architectures of Theories‖ (1893), C. S. Peirce presented his trichotomies within psychology, biology, physics and philosophy, and in terms of these trichotomies, it could easily be predicted, according to Peirce, what kind of metaphysics it would be appropriate to construct, a cosmogonic philosophy. But, other than presenting his very brief sketch of a thoroughgoing...

The Peirce quincuncial projection is a mapping of the surface of a sphere to the interior of a square. It is a conformal mapping except for four points on the equator. These points of non-conformality cause significant artifacts in photographic applications. In this paper, we propose an algorithm and userinterface to mitigate these artifacts. Moreover, in order to facilitate an interactive user...

Peirce grammar provides a first-order, relational semantics for extensional fragments of natural language. Proposals in the literature to model natural language coordination by boolean operations in Peirce grammar lead to inadaequate results. We propose to equip Peirce grammar with an additional sort of finite trees and to admit recursion on trees for defining the evaluation of expressions. We ...