Leave the last word to Jacob Bronowski, speaking at the end of his television series The Ascent of Man. Standing in a pond at Auschwitz-Birkenau, where many of his relatives died, he reached down and lifted up some mud: ‘Into this pond were flushed the ashes of some four million people. And that was not done by gas. It was done by arrogance, it was done by dogma, it was done by ignorance. When people believe that they have absolute knowledge, with no test in reality, this is how they behave. This is what men do when they aspire to the knowledge of gods.’