Hartley Slater and False Contradictions

In this note I say a few words about my interaction with the late Hartley Slater and his work. Si on appelle un chat un chat Cela évite les embrouilles Et on retombe toujours sur ses pattes Baron de Chambourcy 1 From Los Angeles to Helsinki: 20 years of friendship Barry Hartley Slater recently died (July 8, 2016). We are publishing in this issue of the South American Journal of Logic the paper “Gödel’s theorems and the epsilon calculus” that he submitted early this year [17]. His paper “The grammar of platonism” [16] was also recently published in another journal I am managing, Logica Universalis. I take this opportunity to write my interaction with him. I think that interaction is fundamental for research. It is in fact the motor of modern science in particular through peer-reviews and congresses. Internet has accelerated interaction at a speed close to light speed but it is still worth meeting and discussing with people in flesh and blood. My work has been influenced by the encounters with many strangers, Hartley is one them. I virtually met Hartley in 1995 in Los Angeles when I was doing a post-doc at UCLA. My first contact with him was when I was asked to write for Mathematical Review a review [2] of his paper entitled “Paraconsistent logics?” [15]. As I have explained in another paper entitled “The new rising of the square of opposition” [7], this was the starting point of my work on the square of opposition, generating many publications and a series of events: SQUARE – World Congress on the Square of opposition. Slater was invited speaker at the 2nd edition of the SQUARE which took place in June 2010 at the University Pasquale Paoli in Corsica. Below a picture where