Lodovico Settembrini is the Italian humanist of the sanatorium and Hans Castorp's first master: a man of letters, an invalid who cannot leave the mountain, a defender of reason, progress, democracy, and civilization against everything he considers decline.
He enters Chapter III already as a pedagogue. He calls the doctors "our Minos and Rhadamanthus," the judges of the world of the dead, and the patients "fallen people." He cites Carducci's Hymn to Satan as a symbol of rebellious reason, and, on that same night, he suggests that Hans Castorp pack his bags and leave on the train the next day. In Chapter IV he formulates the doctrine: illness is not noble, music is "politically suspect," and literature, morality, and politics form a single force, civilization.
In Chapter VI he gains an adversary, the Jesuit Naphta, and the two contend for years over Hans Castorp's formation. In Chapter VII he accepts the duel, though he disapproves of it, and fires into the air. In his farewell, he sends the disciple down to the plain.
His measure is not health against illness, but reason and courage. The novel gives him eloquence and generosity and still does not let him win: the book's decisive sentence comes from a dream in the snow, not from an argument of his. Even so, he is the only voice that asks for the descent from the first day, and it is that voice that is fulfilled at the end.