The Hexagon of Opposition

Volume 6, Issue 1-2, June 2012

Jean-Yves Béziau, The Power of the Hexagon

André-Aimable Dufatanye, From the Logical Square to Blanché’s Hexagon: Formalization, Applicability and the Idea of the Normative Structure of Thought

Alessio Moretti, Why the Logical Hexagon?

Peter Simons, Approaching the Alethic Modal Hexagon of Opposition

René Guitart, A Hexagonal Framework of the Field F4 and the Associated Borromean Logic

Didier Dubois and Henri Prade, From Blanché’s Hexagonal Organization of Concepts to Formal Concept Analysis and Possibility Theory

Hans Smessaert, The Classical Aristotelian Hexagon Versus the Modern Duality Hexagon

Jan C. Joerden, Deontological Square, Hexagon, and Decagon: A Deontic Framework for Supererogation

Pierre Cartier, How to Take Advantage of the Blur Between the Finite and the Infinite

Dany Jaspers, Logic and Colour

The hexagon of opposition is an extension of the square of opposition proposed by Robert Blanché in the 1950s.

Hexagons, like squares, have many versions: quantification, alethic modalities, deontic modalities, negations ... It is a universal tool that helps to understand many concepts through a structure of opposition.

This issue is connected with the second world congress on the square of opposition which was organized in Corsica, June 17-20, 2010