The Power of the Hexagon

Jean-Yves Beziau (Rio de Janeiro) gives a talk at the MCMP Colloquium (15 Dec, 2011) titled "The Power of the Hexagon". Abstract: In this lecture I will present and discuss the hexagon of opposition, an improvement of the square of opposition due to Robert Blanché. The hexagon of Blanché is made of a triangle of contrariety and a triangle of subcontrariety linked together by the relations of contradiction and subalternation. This hexagon includes the traditional square and can be extended to three dimensional objects giving a better understanding of modalities and negations. I will also show how this simple logical structure based on three oppositions can be applied to many different concepts ranging from logic to music, through metalogic, economy and semiotics.