Diagrams is excited to announce two confirmed keynote speakers:

• Professor Ahti-Veikko Pietarinen, Tallinn University of Technology.

  The Beauty of Graphs. The beauty of logical graphs consists in many facets, including notational simplicity, multi-modality and normativity. This talk aims at understanding the nature of Peirce’s graphical method and its implications to philosophy of logic.

  Professor Pietarinen directs the Chair of Philosophy and currently teaches as a visiting professor at the Centre for the Study of Language and Cognition at Zheijang University in China and as a professor at the University of Helsinki. In his previous career he has worked at the Harvard University as the Houghton Library Visiting Fellow, as a visiting professor at the Kyung Hee University in Republic of Korea and as an adjunct professor at the University of Turku and at the University of Helsinki. Professor Pietarinen’s areas of specialization include Philosophy of Logic & Language, Philosophy of Science, Pragmatism, History of Analytic & American Philosophy and the Philosophy of Mathematics.

• Professor Keith Stenning, University of Edinburgh

  Diagrams and nonmonotonic logic: what is the cognitive relation?
  Keith Stenning is a cognitive scientist working on human reasoning and decision. He has sought to understand how formalisms such as logics can further the business of experimental analysis of human reasoning. His PhD applied logical model theory to the data of discourse processing, and showed how the conventions of exposition (say story telling) conspire to allow the hearer to construct a unique model of the speaker’s discourse which is the basis of their subsequent inferences. Soon after preferred model semantics made Logic Programming (LP) into a nonmonotonic logic ideal for modelling this cooperative process.

  Turning to diagrammatic reasoning to gain perspective on language processing, Seeing Reason (2002) contrasted diagrammatic and sentential systems of teaching logic to analyse what it is that students learn when they learn elementary logic. Returning to discourse, Human Reasoning and Cognitive Science (2008) (with Michiel van Lambalgen) provided evidence that more than one formalism is required to capture the qualitatively different kinds of reasoning that people engage in for the many purposes they pursue.
  Proving a theorem is not telling a story, yet with the richness of modern logic, it is possible to find logics that capture the essences of both activities.

  Recently, he has worked on integrating LP with decision heuristics to provide a nonprobabilistic model of semantic memory involvement in nonmonotonic reasoning (Stenning, Martignon and Varga 2017).

  Somewhere along the way, he became a Foreign Fellow of the Royal Dutch National Academy, and a Distinguished Fellow of the Cognitive Science Society.