  The formal construction of the second-order logic or predicate calculus
essentially adds quantifiers to propositional logic. Why second-order logic
cannot be reduced to that of the first order? How to demonstrate that certain
predicates are of higher-order? What type of order matches the natural
language? Is there a philosophical position behind every logic, even for
classical ones? What philosophical position for what logic in connection to its
expressive power? These are the questions we ask and that we very briefly
sketch as a first reflection. (paper in French)
