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Logical hexagon
open-in-new
<p>In <a href="/facts/Philosophical_logic/Ld8lnKDA">philosophical logic</a>, the logical hexagon (also called the hexagon of opposition) is a <a href="/facts/Conceptual_model/hgysE2kP">conceptual model</a> of the relationships between the <a href="/facts/Truth_value/SY4e2w8l">truth values</a> of six <a href="/facts/Statement_(logic)/CjpWAyxk">statements</a>. It is an extension of <a href="/facts/Aristotle/U2bDlBFW">Aristotle</a>'s <a href="/facts/Square_of_opposition/z9S71UVr">square of opposition</a>. It was discovered independently by both <a href="/facts/Augustin_Sesmat/eHwUnC9V">Augustin Sesmat</a> and <a href="/facts/Robert_Blanch%C3%A9/r9zDp3VI">Robert Blanché</a>. </p><p>This extension consists in introducing two statements U and Y. Whereas U is the <a href="/facts/Logical_disjunction/jbI2EGlM">disjunction</a> of A and E, Y is the <a href="/facts/Logical_conjunction/62uyyn1d">conjunction</a> of the two traditional particulars I and O. </p>