Throughout history almost all humans believed in several stories at the same time and were never absolutely convinced of the truth of any one of them. This uncertainty rattled most religions, which therefore considered faith to be a cardinal virtue and doubt to be among the worst sins possible—as if there were something intrinsically good about believing things without evidence. With the rise of modern culture, however, the tables were turned. Faith began to look increasingly like mental slavery, while doubt came to be seen as a precondition for freedom.
