“Human beings are religious animals. It is psychologically very hard to go through life without the justification, and the hope, provided by religion. You can see this in the positivist scientists of the 19th century. They insisted that they were describing the universe in rigorously materialistic terms – yet at night they attended seances and tried to summon up the spirits of the dead. Even today, I frequently meet scientists who, outside their own narrow discipline, are superstitious – to such an extent that it sometimes seems to me that to be a rigorous unbeliever today, you have to be a philosopher. Or perhaps a priest.”