In what we tell ourselves is an age of reason, we are behaving increasingly irrationally. An astonishing number of people subscribe to celebrity endorsed cults, Mayan armageddon prophecies, scientism, and other varieties of new age, anti-enlightenment philosophies. Millions more advance popular conspiracy theories: AIDS was created in a CIA laboratory, Princess Diana was assassinated, and the 9/11 attacks were an inside job.In The World Turned Upside Down, Melanie Phillips explains that the basic cause of this explosion of irrationality is the slow but steady marginalization of religion. We tell ourselves that faith and reason are incompatible, but the opposite is the case. It was Christianity and the Hebrew Bible, Phillips asserts, that gave us our concepts of reason, progress, and an orderly world on which science and modernity are based.Without its religious traditions, the West has drifted into mass derangement where truth and lies, right and wrong, victim and aggressor are all turned upside down. Scientists skeptical of global warming are hounded from their posts, Israel is demonized, and the US is vilified over the war on terror—all on the basis of blatant falsehoods and obscene propaganda.Worst of all, asserts Phillips, this abandonment of rationality leaves the West vulnerable to its legitimate threats. Faced with the very real challenges of spiraling demographics and violent, confrontational Islamism, the West is no longer willing or able to defend the modernity and rationalism that it once brought into being.