I have the impression that a nice part of our dispute comes from the fact that despite our ambitions, and a decent /technical/ level of understanding of what we are talking about, most of us are (and I am one of the worst...) -- -- pitiful philosophers... Really bad... Confusing the contents and the function/role of the entities, using ambiguous definitions (and confounding objects with their definitions), et j'en passe. Sigh. I decided to reread some philosophical texts, and I suggest one for your evening reading. "Indiscrete Thoughts" by Gian-Carlo Rota, published by Birkhäuser in 1997. Available on the Web. Rota was an active *mathematician* and teacher, and the sense of mathematical constructs was very important for him. It is a very refreshing book, you won't be disappointed. (It contains also some personal views of Rota on his fellows mathematicians. And the analysis of the difference between characters who are "problem solvers", as contrasted with "theoreticians"... Rota was a strong personality, full of "obsessions", and his ideas on the soundness of formal thinking may not convince you, but you should find them interesting. And you will find inside that for Rota the term "should" is very important, even if it impossible to define...) Many thanks to Olivier Danvy, who recommended me this book! Jerzy Karczmarczuk Caen, France.