The Goya fisonomista exhibition analyzes the relationships of Goya’s faces with the physiognomy treatises of the time. These theories update the parallels between humans and animals that were popular as early as the 16th century and which favored the fashion of studying the animality of the human face and its expressions. The essential feature of the faces created by Goya is brutality, as emotions are shown in their purest form. That lucidity, which Goya reaches with the intuition of his genius, is composed of three types of physiognomies: the animal, the pathological and the degraded. That is why it is revealing to compare Goya’s prints with the treatises of the time. During the period of training and activity of the Aragonese painter, the works on physiognomy reached an extraordinary social diffusion in all social classes. Despite the lack of scientific credibility of this pseudo-science which has been part of popular knowledge, it follows rules which subsequently acted as iconographic codes used throughout the history of art.