'The Disciple' (Le Disciple) by Paul Bourget is a seminal 1889 French novel that delves into the profound ethical responsibilities of a philosopher. It chronicles the story of Adrien Sixte, a renowned but morally detached philosopher, and his devoted student, Robert Greslou. Greslou, deeply influenced by Sixte's amoral principles, applies them to a real-life situation, leading to tragic consequences for the young Countess de Fontrailles. The novel provocatively examines the dangerous interplay between intellectual theories and their practical, often devastating, impact on human lives. Bourget critically explores the theme of moral relativism and the potential for intellectual arrogance to corrupt. It's a powerful psychological drama that remains highly relevant in its critique of philosophical doctrines when detached from humanistic values.