The Father of Cartesian Empiricism: Robert Desgabets on the physics and metaphysics of blood transfusion

The period in the history of blood transfusion that I discuss is roughly 1628, the date of publication of Harvey’s work on blood circulation, De Motu Cordis, and 1668, the year of the first allegedly successful transfusion of blood into a human subject by a French physician Jean Denis, and the official order to prohibit the procedure. The subject of special interest in this history is Robert Desgabets (1610-1678), an early defender and teacher of the Cartesian philosophy at St. Maur, in the region of Lorraine, France. Desgabets’ Discourse de la communication ou transfusion du sang Communication or Transfusion of Blood contains a defence and description of the procedure. This three page manuscript is a lecture delivered at one of the meetings held at M. de Montmor in July 1658. Letters and documents which describe the events of these conferences during Desgabets’ eight month stay in Paris in 1658, indicate that he had numerous discussions with the Cartesian physicist Jacques Rohault and also with another leading Cartesian scientist, Gerauld Cordemoy. In addition, Desgabets is said to have frequently attended the meetings where he showed his interest in many scientific questions. I provide evidence that Desgabets was not an arm-chair scientist: he performed experiments, and he designed and created an apparatus to carry out the procedure of blood transfusion. I show how Desgabets’s Cartesian conception of mechanism and body had theological as well as epistemological underpinnings and consequences. For Desgabets, experiments on blood transfusion were as much demonstrations of the truth of the Cartesian metaphysics as they were demonstrations of the possibility of transubstantiation. The role of experiment was to provide demonstrations of the first principles or truths of physics and theology by connecting them to the way God actually made the world. The upshot of Desgabets's treatment of expérience is that it is integral to the knowledge of essences, and hence to the discovery of the truth of things. In placing expérience at the very foundation of true knowledge, Desgabets reconstructs Cartesianism on an empiricist foundation