An air of scandal has always surrounded German idealism. A defender of common sense might already be scandalised by the extraordinary complexity of many German idealists' writings. If their language is difficult, it is partly because the era of idealism belongs to the era of the discovery of the philosophical resources of the German language: the philosopher finding ideas also had to be a writer finding the words to express them. What is more, the idealists seem to abandon "common sense" because they skip the problems of the traditional school logic and seek, instead, a logic of subjectivity and of being. These logics cannot be reduced to the operations of the "understanding" and constitute what the idealists named "reason".