Frederik STJERNFELT 
Peirce’s Notion of Diagrammatical Reasoning
 
 The paper will present Peirce's notions of diagram and diagrammatical reasoning
as centerpieces of his mature theory of signs. Diagrams are complex signs, a structural
subset of icons, the relations of whose parts mirror the relations of some of the parts of
their objects. This makes possible diagrammatical reasoning: the manipulation of diagram parts after certain rules may give access to new knowledge about the object. Diagrams are basically iconic, aided by general symbolic rules for their manipulation and indices for their object reference.
Frederik STJERNFELT, born 1957, is professor at the
Center for Semiotics, Aarhus University. Recent publications include  Diagrammatology (Springer 2007),  Semiotics: Critical Concept in Linguistics, I–IV (ed. with P.
Bundgaard, Routledge 2010);  The Democratic Contradictions of Multiculturalism (with J.-M. Eriksen, Telos
Press 2012). E-mail: semfelt@hum.au.dk.