There are two very different kinds of atheism: the sentimental optimism of John Lennon's Imagine, and the hard, brutal realism of Friedrich Nietzsche's "death of God." Lennon imagines a world without religion, borders, or possessions, where everyone naturally lives in peace. Nietzsche saw more clearly that if God disappears, so does the Christian moral framework that gave the West its ideas of compassion, humility, charity, and care for the weak. But Nietzsche's alternative has its own fatal flaw. A world built on strength, power, and self-assertion cannot explain why the strong should care for the weak — even though every human being spends large portions of life in weakness, dependence, and need.