Robert Blanché

Robert Blanché (1898–1975) was an associate professor of philosophy at the University of Toulouse.

He wrote many books addressing the philosophy of mathematics.

Nine years before, in 1966, he published with Vrin: Structures intellectuelles.

Whereas the logical square or square of Apuleius represents four values: A, E, I, O, the logical hexagon represents six, that is to say, not only A, E, I, O but also two new values: Y and U.

In La Logique et son histoire d' Aristote à Russell, published with Armand Colin in 1970, Robert Blanché, the author of Structures intellectuelles (Vrin, 1966) mentions that Józef Maria Bocheński speaks of a sort of Indian logical triangle to be compared with the square of Aristotle (or square of Apuleius), in other words with the square of opposition.

The logical hexagon, co-discovered independently by Blanché and Augustin Sesmat extends the square of opposition to six statements.