If the decline of Christianity created the modern political zealot - and his crimes - so the evaporation of religious faith among the educated left a vacuum in the minds of Western intellectuals easily filled by secular superstition. There is no other explanation for the credulity with which scientists, accustomed to evaluating evidence, and writers, whose whole function was to study and criticize society, accepted the crudest Stalinist propaganda at its face value. They needed to believe; they wanted to be duped.