Nietzsche treats the human soul as a forest too large for one hunter. The psychologist who wants to study religious experience needs helpers who have lived through it, and he cannot find them. Scholars sent into this ground lose their nerve just when the big hunt begins. So he goes in alone, and he reads religion by what it does to people rather than by what it teaches.
Early Christian faith, he says, was no gentle comfort. It asked a sceptical, tolerant Roman world to sacrifice its freedom, its pride, and its trust in its own mind. It promised to turn every ancient value upside down, and in it the Oriental slave took revenge on Rome's easy indifference. He traces the religious neurosis to three rules, solitude, fasting, and sexual abstinence, and asks why the saint, a sinner turned holy overnight, fascinated everyone. Even the mightiest men bowed before the saint. They sensed a hidden strength of will in his self-denial, and they wondered what danger could make such a sacrifice worth it. Along the way he compares kinds of faith: Greek religion full of gratitude, later religion full of fear, Luther's blunt passion, a Catholic South that holds its faith more deeply than the Protestant North.
At the centre stands his ladder of religious cruelty. First people sacrificed human beings to their god, perhaps the ones they loved best. Then they sacrificed their own strongest instincts. Last, he asks, what was left to give? Comfort, hope, faith in hidden justice, and finally God himself. That last sacrifice, made out of cruelty to oneself, belongs to his own age. Beside it he sets a very different ideal: a person who says yes to the whole of life and would want it again exactly as it was.
Nietzsche's philosopher would use religion as a tool, a discipline that can train rulers, lift the rising, and console ordinary people in hard lives. The danger begins when religion stops being one means among others and rules on its own terms. Then it keeps alive too much that ought to fail, and it protects the suffering at the cost of the strong. His verdict on Christianity's long rule is harsh. It has bred a herd animal, obliging, sickly, and mediocre: the European of the present day.
