In “Book Third,” Nietzsche dissects the construction of knowledge, proposing that “the strength of conceptions” like logic “does not […] depend on their degree of truth” (85) but results, instead, from changes over time in an individual’s relationship to the human herd, and that “the only experiences are moral experiences, even in the domain of sense-perception” (86).

He proposes that logic grows out of the immense illogical chaos of the universe. Here, Nietzsche examines how individuals whose philosophies go against herd-instinct cause “him a sting of conscience–and his neighbour likewise, indeed the whole herd!–it is in this respect that we have most changed our mode of thinking” (87).

In “Book Third,” Nietzsche writes his most famous phrase, “God is dead” (81), and later adds “We have killed him” (90). In ancient times, knowledge was a means to virtue. Eventually that virtue corrupts, to a point. Society no longer values the figures of the Christian church, as it once did, and so, Nietzsche proposes, as the polytheism of the Greeks gives way to that of the Romans, similarly the concept of a monotheistic God loses its value. This occurs, Nietzsche contends, in Martin Luther’s time. Nietzsche explores this in the first half of “Book Third,” and proposes that the idea of man as flawed.