Léon Dumont (1837–77), whose 1875 book "Théorie scientifique de la sensibilité, le plaisir et la peine" Nietzsche read in 1883, seems to have exerted some influence on this concept. Dumont believed that pleasure is related to increases in force. In "The Wanderer" and "Daybreak", Nietzsche had speculated that pleasures such as cruelty are pleasurable because of exercise of power. But Dumont provided a physiological basis for Nietzsche's speculation. Dumont's theory also would have seemed to confirm Nietzsche's claim that pleasure and pain are reserved for intellectual beings, since, according to Dumont, pain and pleasure require a coming to consciousness and not just a sensing.