9th World Congress on the Square of Opposition

Montréal, Canada, June 22-26, 2026

This will be the 9th world congress organized around the square of opposition after very successful previous editions in Montreux, Switzerland 2007; Corte, Corsica 2010; Beirut, Lebanon 2012; Vatican, 2014; Easter Island, 2016, Crete, 2018, Leuven, Belgium 2022, Costa Rica 2024. This is an interdisciplinary event gathering logicians, philosophers, mathematicians, semioticians, theologians, cognitivists, artists and computer scientists.

Are there any intelligent forms of opposition?

First Steps Toward a Digital Database of Aristotelian Diagrams

Access HERE the wonderful Leonardi Database of Square Diagrams, with hundreds of diagrans

Alessio Moretti, The Geometry of Logical Opposition, PhD, University of Neuchâtel, Switzerland, 2009

Jean-Yves Beziau,“The new rising of the square of opposition”, in J.-Y.Beziau and D.Jacquette (eds), Around and Beyond the Square of Opposition, Birkhäuser, Basel, 2012, pp.6-24.

The meeting will end by a final round square table where subalterned people will express their various contrarieties, subcontrarieties and contradictions.

The best papers will be published as a special issue of a journal and in a book, as it was the case in previous editions.