So, can you have religions without a church? Humanism almost qualifies. It sacralises humanity, claiming for us a significance that is not to be derived from either biology or physics. Organised humanism clearly has unified beliefs and practices. It even has the world’s most lugubrious and sentimental hymn: John Lennon’s Imagine. Like all modern religions it has universalist aspirations, claiming to explain the lives of non-believers better than they can do so themselves. It can inspire heroism and self-sacrifice, but also be used to legitimise intolerance – see Sam Harris and his friends.