This chapter shows that one of the peculiarities of Pinel’s (1745–1826) medical appropriation of Condillac is that it combines a critical empirical assessment of both Condillac’s strengths and weaknesses. For Pinel, the problem to be solved is how the dualism of understanding and will can most appropriately serve as a foundation of a medical science of mental alienation. To answer this question, this chapter analyses Pinel’s critical and clinical reception of Condillac from a perspective of the epistemological history of psychopathology, starting out from an encyclopaedia entry by Pinel on mania comprising four recurring argumentative steps: he argues (i) that Condillac’s psychology of the ordinary serves as a means of establishing a cognitive psychopathology; (ii) that the analysis expanded to a medicine of the passions is a means of establishing an affective psychopathology; (iii) that a clinical fact must lead to the correction of Condillac’s intellectualist definition of madness; and (iv) that an exact terminology allows “philosophical medicine” to break with the “jargon” of the physiology of the brain defended by Condillac.