Edmond Goblot’s Traité de logique was the main reference book in French universities for almost half a century. The author in his foreword deals exclusively with the objections raised by a former student of his, Louis Rougier. Against the conservative positionsof his professor, Rougier, who was then in his twenties, took sides with modern logic, as developed by Louis Couturat, and Hilbertian axiomatic method. This paper presents the positions of the two opponents and shows some of the difficulties raised by the shift from traditional philosophical logic to modern mathematical logic, in particular the ambiguities involved in the use of the notion of construction.