As a number of studies have shown, Édouard Claparède (1873-1940) is best known as a psychologist, educator, activist, and founder of the Institut Jean-Jacques Rousseau des Sciences de l'Education in Geneva. But if, as Martine Ruchat wrote, Claparède was "a doctor before he was a psychologist," his initial training, the academic and social space it opened up for him, and the assets it provided him in the period leading up to the founding of the Institut Rousseau in 1912, deserve a closer look. Although he straddled three traditions - medicine, psychology and education - Claparède is remembered only for the last two, although his career began in medicine, and it is difficult to explain his social and professional rise without mentioning his medical background. This is probably due to the richness of his character, as well as the screen effect cast over his medical past by the creation of the Institut Rousseau. What's more, his desire to transcend professional and corporate boundaries and create new "open disciplines" led him to distance himself from his original guild around 1910. Nevertheless, it was here that he found many of his professional and intellectual role models and the contacts he would make throughout his life, not least at the Société Médicale de Genève. Before 1912, Claparède owed much of his network and his scientific and social reputation not only to the fact that he was a doctor, but also to the way he used his training to promote his ideals of openness and the sharing of knowledge. These were crystallized in a mirrored strategy aimed at multiplying exchanges between psychologists, educators, and physicians.